Letteratura scientifica selezionata sul tema "Root traits and exudation"
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Articoli di riviste sul tema "Root traits and exudation":
1
Kawakami, Erika, Mioko Ataka, Tomonori Kume, Kohei Shimono, Masayoshi Harada, Takuo Hishi e Ayumi Katayama. "Root exudation in a sloping Moso bamboo forest in relation to fine root biomass and traits". PLOS ONE 17, n. 3 (24 marzo 2022): e0266131. http://dx.doi.org/10.1371/journal.pone.0266131.
Abstract (sommario):
Exudation by fine roots generally varies with their morphological traits, but the effect of belowground resource availability on the root exudation via root morphological traits and biomass remains unknown. We aimed to determine the effects of morphological and physiological traits on root exudation rates and to estimate stand-scale exudation (Estand) by measuring the mass, length, and surface area of fine roots in a Moso bamboo forest. We measured root exudation as well as morphological and physiological traits in upper and lower plots on a slope with different belowground resource availability. The mean (± S.D.) root exudation rates per mass in the upper and lower slope were 0.049 ± 0.047 and 0.040 ± 0.059 mg C g-1 h-1, respectively, which were in the range of exudation found in woody forest ecosystems. We observed significant relationships between root exudation per mass and root respiration, as well as specific root length and surface area. In contrast, exudation per length and area did not correlate with morphological traits. The morphological traits did not differ between slope positions, resulting in no significant difference in root exudation per mass. Fine root biomass, length, and surface area on a unit ground basis were much higher in the lower than those in the upper slope positions. Estand was higher when estimated by mass than by length and area because the morphological effect on exudation was ignored when scaled using mass. Estand was 1.4–2.0-fold higher in the lower than that in upper slope positions, suggesting that the scaling parameters of mass, length, and area determined the Estand estimate more than the exudation rate per mass, length, and area. Regardless of scaling, Estand was much higher in the Moso bamboo forest than in other forest ecosystems because of a large fine-root biomass.
2
Yang, Liu, Xiuwei Wang, Zijun Mao, Zhiyan Jiang, Yang Gao, Xiangwei Chen e Doug P. Aubrey. "Root Exudation Rates Decrease with Increasing Latitude in Some Tree Species". Forests 11, n. 10 (28 settembre 2020): 1045. http://dx.doi.org/10.3390/f11101045.
Abstract (sommario):
Research Highlights: Understanding of the spatial variation of root exudation on a regional scale can help understand the response of plant physiological activities to environmental changes. Background and Objectives: Although root exudation has become an important topic in belowground ecology, its relationship with root traits and environmental factors is poorly understood. Our objective was to explore how root traits and environmental factors influence root exudation. Materials and Methods: We used a multi-factorial design consisting of three tree species spanning across sites located at three latitudes to assess root exudation dynamics, which was measured using a syringe-basis incubation system. Results: The strongest and clearest effect observed in our study was a decrease in root exudation rates of Korean pine (Pinus koraiensis Sieb. et Zucc.) and larch (Larix gmelinii (Rupr.) Kuze.) at sites located in higher latitudes. Root exudation rates were positively related to mean annual temperature, mean annual precipitation, and negatively related to soil total organic carbon. Conclusions: Root exudation in coniferous species decreased at sites located in higher latitudes. Despite differences in root exudation rate among sites located at different latitudes and species with suitable variation in root morphological traits and environmental factors, we could not identify consistent influencing factors on root exudation rates.
3
Tang, Lanlan, Ming Zhan, Chunhui Shang, Jiayi Yuan, Yibing Wan e Mingguang Qin. "Dynamics of root exuded carbon and its relationships with root traits of rapeseed and wheat". Plant, Soil and Environment 67, No. 6 (21 maggio 2021): 317–23. http://dx.doi.org/10.17221/561/2020-pse.
Abstract (sommario):
Quantifying carbon in root exudates and exploring their influencing factors are essential to understand soil organic carbon dynamics in cropland. A pot experiment was carried out to explore quantitative relations between root exuded carbon and root traits in wheat and rapeseed. The result showed that rapeseed had a similar pattern in root carbon exudation intensity (EI) as the wheat, but its EI per plant was obviously higher than that in wheat. Rapeseed plants had higher EI per root biomass than wheat plants in the early growth period but lower in the late growth period. EI per root biomass in both crops had significant exponential relationships with the specific root length (RL), surface area (RSA), volume (RV), root C/N ratio and root soluble sugar content. However, EI per plant of both crops had a markedly quadratic relationship with RL, RSA, RV and root biomass. During the whole growth period, the rapeseed had cumulative root carbon exudation of 14.09 g/plant, which was almost twice of that in the wheat plant. Root traits had close relations to root carbon exudation in both crops. Quantitative regression models between them could be referred to estimate root C exudation in rapeseed and wheat farmland.
4
Akatsuki, Maiko, e Naoki Makita. "Influence of fine root traits on in situ exudation rates in four conifers from different mycorrhizal associations". Tree Physiology 40, n. 8 (25 aprile 2020): 1071–79. http://dx.doi.org/10.1093/treephys/tpaa051.
Abstract (sommario):
Abstract Plant roots can exude organic compounds into the soil that are useful for plant survival because they can degrade microorganisms around the roots and enhance allelopathy against other plant invasions. We developed a method to collect carbon (C) exudation on a small scale from tree fine roots by C-free filter traps. We quantified total C through root exudation in four conifers from different microbial symbiotic groups (ectomycorrhiza (ECM) and arbuscular mycorrhiza (AM)) in a cool-temperate forest in Japan. We determined the relationship of mass-based exudation rate from three diameter classes (<0.5, 0.5–1.0, and 1.0–2.5 mm) of the intact root system with root traits such as morphological traits including root diameter, specific root length (SRL), specific root area (SRA), root tissue density (RTD) and chemical traits including root nitrogen (N) content and C/N. Across species, the mass-based root exudation rate was found to correlate with diameter, SRA, RTD, N and C/N. When comparing mycorrhizal types, there were significant relationships between the exudation and diameter, SRL, SRA, root N and C/N in ECM species; however, these were not significant in AM species. Our results show that relationships between in situ root exudation and every measured trait of morphology and chemistry were strongly driven by ECM roots and not by AM roots. These differences might explain the fact that ECM roots in this study potentially covaried by optimizing the exudation and root morphology in forest trees, while exudation in AM roots did not change with changes in root morphology. In addition, the contrasting results may be attributable to the effect of degree and position of ECM and AM colonization in fine root system. Differences in fine root exudation relationships to root morphology for the two types of mycorrhizae will help us better understand the underlying mechanisms of belowground C allocation in forest ecosystems.
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Li, Zuwang, Zhi Liu, Guoqiang Gao, Xinlei Yang e Jiacun Gu. "Shift from Acquisitive to Conservative Root Resource Acquisition Strategy Associated with Increasing Tree Age: A Case Study of Fraxinus mandshurica". Forests 12, n. 12 (17 dicembre 2021): 1797. http://dx.doi.org/10.3390/f12121797.
Abstract (sommario):
Tree age has an important effect on the form and function of fine roots. Previous studies have focused on the variations in root morphological and chemical traits among tree ages, while less attention has been given to the physiological traits, impeding a full understanding of the relationship between root resource acquisition strategy and tree age. Here, we measured root morphological (diameter, specific root length, specific root area and tissue density), chemical (nitrogen concentration) and physiological (respiration and exudation rate) traits of young, middle-aged and mature trees of Fraxinus mandshurica in a temperate secondary forest in northeastern China. Our overall aim was to determine how root traits and related resource acquisition strategy change with tree age. The results showed that from young to mature trees, root diameter gradually increased, but specific root length, specific root area, root nitrogen concentration, respiration and exudation rates all decreased, and the significant differences were mainly found between young and mature trees. Pearson’s correlation analysis revealed that the relationships of root respiration and exudation rates to root morphological and chemical traits depended on tree age and the specific traits examined, but these correlations were all significant except for root tissue density when the data were pooled across all tree age classes. Principal component analysis (PCA) showed that the conservative traits represented by root diameter, and the acquisitive traits such as root respiration and exudation rates and related morphological and chemical traits, occupied two ends of the first axis, respectively, while root tissue density occupied one end of the second axis, partially confirming the conceptual framework of “root economics space”. Standardized major axis (SMA) analysis of root exudation and respiration rates showed that young trees allocated more root carbon flux to the formation of root exudation, compared to middle-aged and mature trees. Our findings suggest that root resource acquisition strategy in F. mandshurica appears to shift from an absorptive to conservative strategy associated with increasing tree age, which may have substantial consequences for individual growth and interspecific competition, as well as belowground carbon allocation in ecosystems.
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Ataka, Mioko, Lijuan Sun, Tatsuro Nakaji, Ayumi Katayama e Tsutom Hiura. "Five-year nitrogen addition affects fine root exudation and its correlation with root respiration in a dominant species, Quercus crispula, of a cool temperate forest, Japan". Tree Physiology 40, n. 3 (24 gennaio 2020): 367–76. http://dx.doi.org/10.1093/treephys/tpz143.
Abstract (sommario):
Abstract In forest ecosystems, fine root respiration directly contributes to belowground carbon (C) cycling. Exudation from fine roots indirectly affects C cycling via enhanced microbial decomposition of soil organic matter. Although these root-derived C fluxes are essential components of belowground C cycling, how nitrogen (N) addition affects these fluxes and their correlations remains unclear. In this study, fine root exudation, respiration and chemical/morphological traits were measured in a dominant canopy species, Quercus crispula Blume, found in a cool temperate forest, the Tomakomai Experimental Forest, Hokkaido University, which has undergone 5-year N addition. Soil-dissolved organic carbon (DOC) was also measured in both bulk and rhizosphere soils to evaluate the impact of fine root exudation on soil C cycling. Compared with a control plot with no N treatment, fine roots in the N addition plot exhibited larger diameters and higher N concentrations, but lower specific root lengths and areas. On a root-weight basis, respiration was not different between plots, but exudation was slightly higher under N addition. On a root-area basis, exudation was significantly higher in the N addition plot. Additionally, differences in DOC between rhizosphere and bulk soils were two times higher in the N addition plot than the control plot. Although fine root respiration was positively correlated with exudation in both the control and N addition plots, the ratio of exudation C to respiration C decreased after 5-year N addition. Nitrogen addition also affected absolute C allocation to fine root exudation and changed the C allocation strategy between exudation and respiration fluxes. These findings will help enhance predictions of belowground C allocation and C cycling under N-rich conditions in the future.
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Wen, Zhihui, Philip J. White, Jianbo Shen e Hans Lambers. "Linking root exudation to belowground economic traits for resource acquisition". New Phytologist 233, n. 4 (4 dicembre 2021): 1620–35. http://dx.doi.org/10.1111/nph.17854.
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Miller, Sarah B., Adam L. Heuberger, Corey D. Broeckling e Courtney E. Jahn. "Non-Targeted Metabolomics Reveals Sorghum Rhizosphere-Associated Exudates are Influenced by the Belowground Interaction of Substrate and Sorghum Genotype". International Journal of Molecular Sciences 20, n. 2 (19 gennaio 2019): 431. http://dx.doi.org/10.3390/ijms20020431.
Abstract (sommario):
Root exudation is an important plant process by which roots release small molecules into the rhizosphere that serve in overall plant functioning. Yet, there is a major gap in our knowledge in translating plant root exudation in artificial systems (i.e., hydroponics, sterile media) to crops, specifically for soils expected in field conditions. Sorghum (Sorghum bicolor L. Moench) root exudation was determined using both ultra-performance liquid chromatography and gas chromatography mass spectrometry-based non-targeted metabolomics to evaluate variation in exudate composition of two sorghum genotypes among three substrates (sand, clay, and soil). Above and belowground plant traits were measured to determine the interaction between sorghum genotype and belowground substrate. Plant growth and quantitative exudate composition were found to vary largely by substrate. Two types of changes to rhizosphere metabolites were observed: rhizosphere-enhanced metabolites (REMs) and rhizosphere-abated metabolites (RAMs). More REMs and RAMs were detected in sand and clay substrates compared to the soil substrate. This study demonstrates that belowground substrate influences the root exudate profile in sorghum, and that two sorghum genotypes exuded metabolites at different magnitudes. However, metabolite identification remains a major bottleneck in non-targeted metabolite profiling of the rhizosphere.
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Cardenas, Julian, Fernando Santa e Eva Kaštovská. "The Exudation of Surplus Products Links Plant Functional Traits and Plant-Microbial Stoichiometry". Land 10, n. 8 (11 agosto 2021): 840. http://dx.doi.org/10.3390/land10080840.
Abstract (sommario):
The rhizosphere is a hot spot of soil microbial activity and is largely fed by root exudation. The carbon (C) exudation flux, coupled with plant growth, is considered a strategy of plants to facilitate nutrient uptake. C exudation is accompanied by a release of nutrients. Nitrogen (N) and phosphorus (P) co-limit the productivity of the plant-microbial system. Therefore, the C:N:P stoichiometry of exudates should be linked to plant nutrient economies, plant functional traits (PFT) and soil nutrient availability. We aimed to identify the strongest links in C:N:P stoichiometry among all rhizosphere components. A total of eight grass species (from conservative to exploitative) were grown in pots under two different soil C:nutrient conditions for a month. As a result, a wide gradient of plant–microbial–soil interactions were created. A total of 43 variables of plants, exudates, microbial and soil C:N:P stoichiometry, and PFTs were evaluated. The variables were merged into four groups in a network analysis, allowing us to identify the strongest connections among the variables and the biological meaning of these groups. The plant–soil interactions were shaped by soil N availability. Faster-growing plants were associated with lower amounts of mineral N (and P) in the soil solution, inducing a stronger competition for N with microorganisms in the rhizosphere compared to slower-growing plants. The plants responded by enhancing their N use efficiency and root:shoot ratio, and they reduced N losses via exudation. Root growth was supported either by reallocated foliar reserves or by enhanced ammonium uptake, which connected the specific leaf area (SLA) to the mineral N availability in the soil. Rapid plant growth enhanced the exudation flux. The exudates were rich in C and P relative to N compounds and served to release surplus metabolic products. The exudate C:N:P stoichiometry and soil N availability combined to shape the microbial stoichiometry, and N and P mining. In conclusion, the exudate flux and its C:N:P stoichiometry reflected the plant growth rate and nutrient constraints with a high degree of reliability. Furthermore, it mediated the plant–microbial interactions in the rhizosphere.
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Marschmann, Gianna L., Jinyun Tang, Kateryna Zhalnina, Ulas Karaoz, Heejung Cho, Beatrice Le, Jennifer Pett-Ridge e Eoin L. Brodie. "Predictions of rhizosphere microbiome dynamics with a genome-informed and trait-based energy budget model". Nature Microbiology 9, n. 2 (5 febbraio 2024): 421–33. http://dx.doi.org/10.1038/s41564-023-01582-w.
Abstract (sommario):
AbstractSoil microbiomes are highly diverse, and to improve their representation in biogeochemical models, microbial genome data can be leveraged to infer key functional traits. By integrating genome-inferred traits into a theory-based hierarchical framework, emergent behaviour arising from interactions of individual traits can be predicted. Here we combine theory-driven predictions of substrate uptake kinetics with a genome-informed trait-based dynamic energy budget model to predict emergent life-history traits and trade-offs in soil bacteria. When applied to a plant microbiome system, the model accurately predicted distinct substrate-acquisition strategies that aligned with observations, uncovering resource-dependent trade-offs between microbial growth rate and efficiency. For instance, inherently slower-growing microorganisms, favoured by organic acid exudation at later plant growth stages, exhibited enhanced carbon use efficiency (yield) without sacrificing growth rate (power). This insight has implications for retaining plant root-derived carbon in soils and highlights the power of data-driven, trait-based approaches for improving microbial representation in biogeochemical models.
Tesi sul tema "Root traits and exudation":
1
Guyonnet, Julien. "Effet de la stratégie de gestion des ressources des plantes sur l’investissement dans l’exsudation racinaire, et les conséquences sur les communautés bactériennes". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1008.
Abstract (sommario):
L'exsudation racinaire est connue pour avoir une influence sur le fonctionnement des communautés microbiennes, en particulier celles impliquées dans le cycle de l'azote (Haichar et al, 2012). Elle est liée à la physiologie de la plante, cette dernière pouvant être évaluée via les traits fonctionnels végétaux, permettant une classification des plantes en fonction de leur performance dans leur environnement. Ainsi, nous pouvons distinguer d'une part les espèces exploitatrices, avec une efficience de la photosynthèse élevée et une acquisition rapide de l'azote dans les sols, et d'autre part les plantes conservatrices, possédant des caractéristiques contraires (Aerts & Chapin, 1999) et des plantes intermédiaires dont les caractéristiques sont intermediaires.L'objectif de ces travaux de thèse est de déterminer l'influence de la stratégie de gestion des ressources de 6 poacées, réparties le long d'un gradient de stratégie de gestion des ressources, allant de stratégies conservatrices (Sesleria caerulea et Festuca paniculata), intermédiaires (Antoxanthum odoratum, Bromus erectus) à des stratégies exploitatrices (Dactylis glomerata et Trisetum flavescens), sur la diversité et le fonctionnement des communautés totales et dénitrifiantes. I) Dans un premier temps nous avons étudié le lien entre la stratégie de gestion de ressources des plantes et la quantité d'exsudats racinaires dans le sol adhérent aux racines (SAR). Nous avons ensuite déterminé l'influence de la quantité d'exsudats racinaire sur les activités microbiennes potentielles des communautés microbiennes du SAR (respiration et dénitrification potentielles), puis par une approche ADN-SIP (Stable Isotope Probing) couplée à du séquençage haut-débit, l'influence de l'exsudation racinaire sur la structure et la diversité des communautés bactérienne colonisant le SAR et le système racinaire. II) Dans un second temps, nous avons étudié le lien entre la stratégie de gestion des ressources des plantes et la nature des exsudats racinaires libérés au niveau du SAR et présents dans les extraits racinaires en analysant les profils des métabolites primaires chez Festuca paniculata, Bromus erectus et Dactylis glomerata, représentant respectivement des stratégies de gestion des ressources conservative, intermédiaire et exploitatriceRoot exudation is known to influence microbial communities functioning, in particular those involve in nitrogen cycle. (Haichar et al, 2012). It’s linked to plant physiology, which can be evaluated with functional traits, allowing a plant distribution in function of their performance in their environment. Thus, we can distinguish competitive species, with higher photosynthetic capacity and rapid rates of N acquisition, conservative species with the opposite characteristics (Aerts & Chapin, 1999) and intermediate plants, with intermediate characteristics.The objective of this work is to determinate the influence of nutrient management strategiy of 6 poaceae, along a strategies gradient from conservative strategy (Sesleria caerulea and Festuca paniculata), intermediate (Antoxanthum odoratum and Bromus erectus) to competitive strategy (Dactylis glomerata and Trisetum flavescens), on diversity and functioning of total and denitrifying communities.I) Firstly, we studied the link between the plant nutrient management strategy and the root exudates quantity in the root adhering soil (RAS). Then, we determined the influence of the rate of root exudation on potential microbial activities (respiration and denitrification), and with a DNA-SIP (Stable Isotope Probing) approach coupled to high-throughput sequencing, the influence of root exudation on the bacterial structure and diversity of communities colonizing the RAS and the root system. II) Secondly, we studied the link between the plant nutrient management strategy and the nature of molecules exuded in RAS and present in root extracts by analyzing primary metabolites profile to Festuca paniculata, Bromus erectus and Dactylis glomerata, respectively a conservative, an intermediate and a competitive plant. Then, we determined the influence of primary metabolites profile of each plant on semi-real denitrification of communities colonizing RAS of plants. III) Finally, an mRNA-SIP approach is in progress to determine the influence of exuded metabolites on active bacterial communities functioning and the expression of genes involved in denitrification process in RAS and root system. Our results show an influence of the nutrient management strategy on the rate of carbon exudation, the competitive plants exuding more than conservatives ones
2
Delamare, Jeremy. "Analyses de deux stratégies d’acclimatation à un stress thermique intense reposant sur une thermo-sensibilisation ou une sensibilisation médiée par des bactéries PGPR chez le colza et la caméline". Electronic Thesis or Diss., Normandie, 2023. http://www.theses.fr/2023NORMC243.
Abstract (sommario):
Le changement climatique auquel nous sommes confrontés est caractérisé notamment par une modification des profils thermiques en termes d’intensité, de durée et de répétition des vagues de chaleur. Ces vagues de chaleur surviennent lors des stades reproducteurs des plantes qui sont également les plus critiques pour l’élaboration des composantes de rendement et des critères de qualité grainière des grandes cultures. Les oléagineux tels que le colza et la caméline sont des espèces particulièrement impactées par le stress thermique, causant de fortes pertes de rendement et une diminution de la qualité grainière. Ainsi, il est nécessaire d’identifier de nouveaux leviers d’acclimatation, telles que des stratégies reposant sur l’acclimatation des plantes. Le thermopriming consistant à préparer les plantes à répondre de façon plus rapide, efficace, intense et/ou sensible à un stress thermique par une exposition préalable à un stress de même nature pourrait permettre d’acclimater les plantes qui mettraient en place des mécanismes de réponses adaptés. L’inoculation des plantes avec des PGPR est un levier d’acclimatation de plus en plus étudié, qui permet de limiter les impacts du stress thermique. Cependant, bien que ces deux types de stratégies d’acclimatation soient principalement étudiés pour limiter l’impact des stress sur le développement des parties aériennes et sur le rendement, peu d’études se sont intéressées à leurs effets sur la morphologie et les fonctions racinaires comme l’exsudation racinaire. Dans le cadre de cette thèse, nous avons analysé chez le colza et la caméline (i) d’une part les effets d’une augmentation graduelle de température précédant un stress thermique, sur le rendement et la qualité grainière et sur la morphologie et l’exsudation racinaire et (ii) d’autre part les effets de l’inoculation de deux Pseudomonas présentant des activités PGPR afin de limiter les impacts du stress thermique sur le rendement et la qualité grainière. De plus, afin de connaitre l’impact du stress thermique et de l’inoculation de PGPR (combinés ou non) sur la plante et la rhizosphère associée, les effets de ces traitements ont été étudiés sur l’exsudation racinaire, l’allocation de carbone (C) dans le système sol-plante, les traits morphologiques racinaires et les communautés microbiennes du sol. Nos résultats ont montré que le colza et la caméline présentent des stratégies contrastées quant à leur réponse au stress thermique. En effet, la caméline semble réagir au stress en augmentant son investissement dans les parties racinaires, en améliorant qualitativement son exsudation et en stimulant l’activité des communautés microbiennes à l’inverse du colza qui semble plutôt endurer le stress. De plus, ces deux espèces ont réagi différemment aux deux stratégies d’acclimatation appliquées. En effet, chez le colza, le thermopriming a permis de diminuer l’exsudation en C et de maintenir son rendement et sa qualité grainière alors qu’il a eu un impact plus négatif sur l’exsudation et la morphologie racinaire chez la caméline. L’inoculation des PGPR est une stratégie d’acclimatation qui tend à limiter les effets du stress thermique sur le rendement et la qualité grainière chez le colza. Cependant, les PGPR agissent comme un puits supplémentaire chez le colza impactant son développement, son exsudation ainsi que l’activité et la composition des communautés microbienne. A l’inverse, la caméline est peu impactée par l’apport de PGPR et semble par conséquent piloter les interactions plante/bactéries plutôt que les subir. En résumé, ces leviers d’acclimatation semblent démontrer des effets bénéfiques pour les plantes. De plus, il pourrait être intéressant d’intégrer les effets de la sélection variétale sur les stratégies de réponses des plantes face au stress et notamment la variabilité des fonctions racinaires et des interactions avec la rhizosphère, à la lumière de la sélection variétale différentiellement subie par le colza et la camélineThe on-going climate changes that we are facing are characterized in particular by modifications of temperature profiles in terms of intensity, duration and repetition of heat waves. These heat waves occur during the reproductive stages of the crops, which are also the most critical for seed yield elaboration and grain quality in crops. Oleaginous species such as rapeseed and camelina, are species particularly impacted by heat stress that cause yield penalties and a lower seed quality. Therefore, to cope with heat stress, it has become necessary to identify new acclimation levers that differ avec genetic and agronomic levers, such as strategies based on plants acclimation. Thermopriming which consist in priming the plants in a way to help them respond more rapidly, effectively, intensively and/or sensitively to heat by a prior exposure of a stress of the same nature could allow the plants to acclimate and develop appropriate response mechanisms. The plant inoculation with Plant Growth Promoting Rhizobacteria (PGPR)-type bacteria is also an acclimation lever increasingly studied, that limit the impacts of abiotic stress such as heat stress. However, although these two types of acclimation levers are mainly studied to limit stress impact on aboveground development and yield, few studies have observed their effects on root morphology and functions such as root exudation. In this thesis we analysed in rapeseed and camelina (i) the effects of a gradual increase in temperature prior a heat stress on yield and grain quality and on root morphology and exudation and (ii) the effects of inoculating two Pseudomonas with PGPR activities in order to limit the impact of heat stress on yield and grain quality. Moreover, in order to understand the impact of heat stress and PGPR inoculation (combined or not) on the plant and associated rhizosphere, the effects of these treatments were studied on root exudation, carbon (C) allocation in the soil-plant system, root morphological traits and soil microbial communities. Our results showed that rapeseed and camelina have contrasting strategies in terms of response to heat stress. Indeed, camelina seems to respond to the stress by increasing its investment to the roots thus improving the quality of exudation and stimulating the activity of microbial communities, unlike rapeseed, which seems to undergo heat stress. In addition, these two species respond differently to the two acclimation strategies applied. In rapeseed, thermopriming reduced C exudation and maintained yield and grain quality, whereas it had a more negative impact on exudation and root morphology in camelina. PGPR inoculation is an acclimation strategy that tends to limit the effects of heat stress on yield and grain quality in rapeseed. However, PGPRs act as an additional sink in rapeseed, impacting its development, exudation and the activity and composition of microbial communities in the rhizosphere. By contrast, camelina is slightly affected by the addition of PGPRs and seems to control the plant/bacteria interactions rather than be affected by them. In short, beneficial effects on plants of these acclimation levers have been evidenced. In addition, it could be interesting to integrate the effects of varietal selection on plant response strategies to stress, and in particular the variability of root functions and interactions with the rhizosphere, in the light of the varietal selection differentially undergone by rapeseed and camelina
3
Plum, Sara A. "Manipulation of sources and sinks of grasses : growth, photosynthesis and root exudation". Thesis, Bangor University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389504.
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Roworth, Joshua David. "The characterisation of root exudation and colonisation in the rhizosphere of land plants". Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:0f21602e-73c7-4470-a598-ec9f16093190.
Abstract (sommario):
The rhizosphere of land plants is a diverse and complex environment that is critical to the life cycles of plants. Plants release photosynthetically fixed carbon into the rhizosphere that can act to solubilise nutrients, detoxify metals, and modify soil microbial communities. Within these soil microbial communities a diverse range of microbes exist, ranging from the beneficial plant growth promoting rhizobacteria to plant pathogens. These microbes must be able to effectively colonise the rhizosphere and plant rooting systems for their survival. To study root exudation and the bacterial colonisation of the roots two separate techniques were used. To study the spatial and temporal release of exudation in Oryza sativa, Zea mays, Arabidopsis thaliana, and Marchantia polymorpha, luciferase based bioreporters, which respond to plant derived carbon were used. These bioreporters based in Rhizobium leguminosarum allowed for the production of maps showing the spatial nature of exudation from plant roots, alongside changes in exudation temporally. In this work I showed that the release of the C4-Dicarboxylic acids was conserved across all plant species tested. Moreover, the release of these exudates occurred on specific rooting structures, such as lateral roots, and not across the whole rooting system. This work has shown that R. leguminosarum based bioreporters can be flexibly used across a range of different plant species. For studying the genetic basis of Azorhizobium caulinodans colonisation of the O. sativa rhizosphere, a technique known as insertion sequencing was used. This technique highlighted bacterial genes involved in rhizosphere and root colonising growth. Using these data, several interesting gene operons were identified that played a crucial role in rhizosphere growth. One example was a putative propionate catabolism operon, indicating that A. caulinodans is using plant-derived propionate as a carbon source for growth. Insertion sequencing was also used to probe the genetic basis of nitrogen fixation in A. caulinodans, here I showed that insertion sequencing was applicable to this study and could identify a number of genes involved in low nitrogen growth.
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Holz, Maire [Verfasser], e Andrea [Akademischer Betreuer] Carminati. "Biophysical factors controlling root exudation and rhizosphere extension / Maire Holz ; Betreuer: Andrea Carminati". Bayreuth : Universität Bayreuth, 2020. http://d-nb.info/1209196565/34.
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MUELLER, KEVIN E. "INVESTIGATIONS INTO THE USE OF TREES FOR PHYTOREMEDIATION OF PAH CONTAMINATED SOILS". University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1123258067.
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Rummel, Pauline Sophie [Verfasser]. "Nitrate uptake, root exudation, and litter quality - crop plant effects on denitrification and its product stoichiometry / Pauline Sophie Rummel". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2021. http://d-nb.info/1236401689/34.
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De, Lucchi Chiara. "Improving key root traits in sugar beet: Fusarium resistance". Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424410.
Abstract (sommario):
The challenge of the twenty-first century is to produce enough food to meet population demands without extending land or damaging the environment. Combining a maximum number of desirable traits such disease resistance, greater yield, and high quality is a desirable goal for plant breeders. The development of resistant crop genotypes is essential to ensure global food security, make the plant more useful and avoid crop losses. The development of molecular markers linked to the target traits is needed to predict phenotypic variation based on genotype. Marker-Assisted Selection (MAS) can reduce costs and the time required to obtain new cultivars by comparing selection only based on phenotypic evaluation. Single nucleotide polymorphisms (SNPs) are widely used as genetic marker.
Sugar beet (Beta vulgaris L.) is the second source of world sugar supply and is grown in all temperate zones. The crop is attacked by many pathogens and among these, the soil-borne fungus Fusarium oxysporum causes severe sugar beet damages. Two different formae speciales have been reported in sugar beet, F. oxysporum f. sp. betae that causes Fusarium yellows, and F. oxysporum f. sp. radicis-betae that causes Fusarium root rot. Disease symptoms are characterized by wilt and yellow leaves that normally die as the disease progresses. Internal symptoms consist of a brown or grey brown vascular discoloration and in the case of root rot, there is a back external rot in the primary root. Sugar beet varieties are susceptible to F. oxysporum, which can cause a lower root yield and reduce sugar quality. No genetic studies have been done up to now, so no genes or quantitative trait loci (QTLs) conferring resistance to F. oxysporum in sugar beet have been reported. The aims of this work were (i) to investigate the response of a wide collection of sugar beet lines to F. oxysporum f. sp. betae, (ii) to identify resistant lines suitable for future breeding efforts and (iii) to discover molecular markers linked to the Fusarium resistance that could be considered for use in marker-assisted selection (MAS) programs.
The first part of the thesis is a literature review of sugar beet breeding achievements, including the discovery of monogermity and cytoplasmic-genetic male sterility (CMS) that allowed the release of hybrid varieties. The review also focused on the breeding progresses against diseases obtained with classical and molecular methods using sources of resistance from wild beets. Next-generation sequencing (NGS) technologies with the recent release of the full sugar beet genome sequence are also reported. Incorporation of genomics into conventional sugar beet breeding programs is essential to obtain important yield achievements in sugar beet.
The second part was aimed at screening a wide range of sugar beet lines to identify the different effect to F. oxysporum f. sp. betae inoculation and to select resistant and susceptible lines. To achieve this, 29 sugar beet lines were screened under greenhouse conditions with two highly virulent isolates belonging to different genetic sub-groups.
The third part regards an experiment conducted to evaluate the response of different sugar beet breeding germplasm to isolates of F. oxysporum f. sp. betae. In the previously tested lines, an unusual root rot was observed, normally reported in cases of infection with F. oxysporum f. sp. radicis-betae. Eight susceptible lines, from USDA-ARS (US) and UNIPD (University of Padova, Italy), were inoculated with three different isolates of F. oxysporum f. sp. betae, the causal agent of Fusarium yellows. All inoculated lines developed disease symptoms, but severe root rot was observed only in the susceptible UNIPD lines inoculated with isolates that had never caused root rot in the USDA germplasm. In this work, an unusual root rot was reported for the first time that seems to be caused not only by the isolates, but is also due to a germplasm effect.
The fourth part was aimed to identify molecular SNP markers linked to the Fusarium resistance in sugar beet. A candidate gene approach was used on susceptible and resistant lines to achieve this goal. Five resistant gene analogues were screened by means of a high-resolution melting (HRM) analysis and two allelic variants, within two genes, were significantly associated to Fusarium resistance. Sanger sequencing allowed the discovery of two SNP markers linked to the resistance. These two SNPs were significantly associated with the resistance and were mapped on the exon of Bv7_171470_ojty and Bv2_043450_zhxk, respectively.Il miglioramento genetico delle piante coltivate, basato sull’esplorazione, sull’utilizzo delle risorse genetiche e sulla ricerca genomica avanzata, è prioritario per soddisfare il fabbisogno alimentare di una popolazione mondiale in costante crescita. In particolare, l’introgressione di tratti desiderabili come la resistenza alle malattie e la maggior resa produttiva è fondamentale per garantire la sicurezza alimentare a livello globale. Per accelerare il miglioramento delle piante è essenziale predire le variazioni fenotipiche sviluppando marcatori molecolari legati ai tratti in esame. La selezione assistita da marcatori molecolari può ridurre costi e tempi di ottenimento di nuove varietà rispetto alla selezione basata solo su variazioni fenotipiche. Fra i marcatori molecolari disponibili, le mutazioni di singola base (SNP) sono i più diffusi. La barbabietola da zucchero (Beta vulgaris L.) è la seconda fonte di zucchero al mondo ed è coltivata in tutte le aree temperate. La coltura è colpita da numerosi patogeni e, fra questi, il fungo Fusarium oxysporum causa severi danni. Due differenti forme speciali di Fusarium, Fusarium oxysporum f. sp. betae (Fusarium yellows) e Fusarium oxysporum f. sp. radicis-betae (Fusarium root rot) sono state identificate in barbabietola. La malattia è caratterizzata da avvizzimento e clorosi fogliare con un progressivo deperimento delle foglie, spesso seguito dalla morte dell’intera pianta. I sintomi interni consistono in una discolorazione vascolare con imbrunimento dei fasci vascolari e, nel caso di marciume radicale, è presente un caratteristico annerimento all’esterno della radice principale. Per il controllo del patogeno, l’impiego di fungicidi e le rotazioni colturali non sono efficaci. L’introgressione di geni di resistenza dal germoplasma selvatico è ritenuta la strategia principale per la difesa della coltura. Questo richiede lo sviluppo di marcatori molecolari legati ai geni di resistenza per la selezione assistita degli individui resistenti. Gli obiettivi del lavoro di tesi sono stati i seguenti: (i) valutare la risposta a Fusarium oxysporum f. sp. betae di un’ampia collezione di linee di barbabietola da zucchero (ii) identificare linee resistenti a Fusarium oxysporum da poter utilizzare in futuri programmi di miglioramento genetico e (iii) identificare marcatori molecolari SNP (polimorfismi del DNA a singolo nucleotide) legati alla resistenza a Fusarium da utilizzare in programmi di selezione assistita da marcatori. Il primo contributo del lavoro di tesi descrive lo stato dell’arte dei risultati ottenuti nel miglioramento genetico della barbabietola da zucchero. Il contributo si focalizza sui progressi ottenuti nella resistenza a malattie con metodi di miglioramento genetici classico e con l’impiego di tecniche molecolari utilizzando come fonte di resistenza germoplasma selvatico. E’ stato inoltre considerato il contributo delle nuove tecnologie di sequenziamento e del recente rilascio del genoma di riferimento al miglioramento genetico della barbabietola. Il secondo contributo riguarda la valutazione della risposta a Fusarium oxysporum f. sp. betae di un’ampia collezione di linee di barbabietola da zucchero al fine di identificare linee resistenti e suscettibili. Per raggiungere questo scopo sono state esaminate 29 linee di barbabietola da zucchero. Le piante sono state infettate con due isolati fungini F19 e Fob220a, appartenenti a due gruppi genetici distinti, entrambi altamente patogenici. Dopo l’inoculo, per un periodo di sei settimane, è stato attribuito, per ciascuna pianta, un punteggio da 0 a 5 in base ai vari sintomi di malattia manifestati, quali: avvizzimento fogliare, clorosi e necrosi. Successivamente, le piante sono state raccolte e le radici sono state esaminate per vedere dove era presente marciume radicale, discolorazione e quali piante invece risultavano resistenti al patogeno. Il terzo contributo descrive la risposta di due diverse collezioni di germoplasma di barbabietola da zucchero a isolati di Fusarium oxysporum f. sp. betae. Linee suscettibili, provenienti da USDA-ARS (US) e UNIPD (Università di Padova, Italia), sono state inoculate con tre distinti isolati di Fusarium oxysporum f. sp. betae, l’agente causa di Fusarium yellows. Tutte le linee inoculate hanno sviluppato i sintomi della malattia, ma un grave marciume radicale è stato osservato solo nelle linee provenienti da UNIPD inoculate con isolati che non avevano mai causato marciume radicale nel germoplasma USDA. Il quarto contributo riguarda l’identificazione, su geni candidati, di marcatori molecolari SNPs associati alla resistenza alla malattia. In particolare, sono stati identificati 5 analoghi a geni di resistenza (RGA) dal lavoro di Dohm et al. 2014 e sono stati analizzati tramite analisi High Resolution Melting (HRM) su 96 campioni delle 6 linee più resistenti e più suscettibili a Fusarium. Due varianti, in 2 dei geni testati, sono risultate significativamente associate (p < 0.01) con la resistenza a Fusarium. Le varianti sono state validate attraverso sequenziamento Sanger. Il sequenziamento ha permesso di individuare due marcatori SNPs. L’associazione tra questi due SNPs e la resistenza a Fusarium è stata successivamente validata con il metodo di genotipizzazione Comparative allele-specific PCR (KASPar) su 96 campioni resistenti e 96 campioni suscettibili. La frequenza dell’allele A sia per lo SNP_Bv7_171470 e lo SNP_Bv2_043450 è risultata significativamente più alta negli individui resistenti rispetto a quelli suscettibili. Questi due SNPs potranno essere utilizzati in programmi di selezione genetica al fine di migliorare la resistenza a Fusarium in barbabietola da zucchero.
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Scott, Gavin D. "Root system traits and root longevities in two contrasting cultivars of Trifolium repens (White clover)". Thesis, University of Aberdeen, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425002.
Abstract (sommario):
This study uses sequential digital imaging of rhizotron grown root systems of white clover (Trifolium repens) to evaluate the developmental differences in the architecture of two cultivars with contrasting above-ground characteristics. Root lengths and leaf areas were correlated in both cultivars, with large leaved Alice producing greater leaf area and greater root length than the small leaved S184. The key architectural difference between the two cultivars was that Alice produced a higher ratio of terminal lateral length to axial length than S184. Lateral roots had lower survival times compared with axial roots in both cultivars. Amongst lateral roots, survival was positively influenced by diameter. A 0.1 mm increase in diameter was calculated to result in between 23% and 42% reduction in the risk of lateral root mortality. Destructive investigations of the root systems were made at intervals during the experiment and roots of known age and order were excised and evaluated for C and N content and tissue density. Axial roots were found to have higher tissue density and higher C and N content than laterals, and, these traits increased with increasing axial root age. The hypothesis that axial roots are invested with additional high C compounds to increase their persistence in the soil was supported by microscopic analysis which shown a build up of lignin in axial roots as they aged. A population dynamics model was constructed showing the estimated flux of C and N from plant to soil due to root mortality. The most dynamic C and N pool was in the lateral roots. Breeding and selection of white clover cultivars should aim to maximise the ephemeral lateral root system component to enhance N flux from plant to soil.
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Patel, Dhaval V. "Dissecting natural variation of root traits in arabidopsis thaliana accessions". Thesis, University of Nottingham, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503910.
Libri sul tema "Root traits and exudation":
1
Esler, Karen J., Anna L. Jacobsen e R. Brandon Pratt. Organisms and their Interactions. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198739135.003.0003.
Abstract (sommario):
Both animal and plant species exhibit adaptive traits related to features of mediterranean-type ecosystems (MTEs). For plants, the seasonality of the MTC has been an important factor in the evolution of plant phenological traits. Root adaptive traits that improve nutrient extraction from impoverished soils are present within MTC regions, including cluster roots, root nodules, and mycorrhizal symbioses. Fire has been an important driver of plant traits, such as smoke, charate, or heat-induced seed germination or seed release (i.e. serotiny), and post-fire flowering. Adaptive traits in animals include both physiological and behavioural traits. MTC regions have been used in the study of many ecological and evolutionary patterns, particularly as related to organismal adaptations to unique soil and substrates (edaphic communities) and interactions between plants and animals, such as plant–herbivore interactions, plant–pollinator interactions, and plant–seed disperser interactions. These interactions shape many plant and animal characters within MTC regions.
2
Martinho-Truswell, Antone. The Parrot in the Mirror. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780198846109.001.0001.
Abstract (sommario):
Abstract This book explores animal evolution and behaviour to explain how humans and birds came to share so much. How did we come to be so bird-like? Considering the answer to this question leads to an examination of the animal world that highlights fundamental and profound aspects of biology. The book looks at the value of movement in animals; the way in which traits such as intelligence, size, long life span, and the birth of very immature young are all interconnected. Above all, it assesses how even very different forms of life, experiencing similar evolutionary pressures from their environments, can hit on similar solutions – the phenomenon known as convergent evolution. It is that which lies at the root of our bird-ishness.
3
Faxneld, Per. Woman and the Devil. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190664473.003.0002.
Abstract (sommario):
Chapter2 provides a background for the main motifs of the study. It commences with a survey of the development of the figure of Satan and Satanism, and then discusses Genesis 3, the narrative that lies at the root of most of the later ideas about Satan’s intimate ties to woman. The interpretations of this text by Gnostics, Church Fathers, and reformers are delineated. This is followed by an examination of the notion of the Devil as a woman, whereafter the enigmatic entity Baphomet—an example of how Satan has been given female or hermaphroditic traits in esoteric writings—is considered. Thereupon, some background is provided on the Jewish demoness Lilith, who was seen as the first feminist in several nineteenth-century interpretations. Next, some motifs in folklore and witchcraft trials are treated, followed by a brief exploration of ideas concerning erotic relations between women and Satan.
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Churchill, Robert Paul. Women in the Crossfire. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190468569.001.0001.
Abstract (sommario):
Every year, thousands of girls and women die, often at the hands of blood relatives. These victims are accused of committing honor violations that bring shame upon their family—such transgressions range from walking with a boy in their neighborhood to seeking to marry a man of their own choosing to being a victim of rape. Women in the Crossfire presents a thorough examination of honor killing, an age-old social practice through which women are trapped and subjected to terror and deadly violence as consequences of the evolution of dysfunctional patriarchal structures and competition among men for domination. To understand the practice of honor killing, its root causes, and possibilities for protection and prevention, this book considers the issues from a variety of perspectives (epistemic, anthropological, sociological, cultural, ethical, historical, psychological, etc.) and makes use of original research—an analysis of a database of honor killing cases, published here for the first time. Specifically, the book addresses the salient traits and trends present in honor killing incidents and examines how honor is understood in sociocultural contexts where these killings occur. It illuminates socialization factors within honor-shame cultures that include gender construction, child-rearing practices, and adverse experiences that prime boys and men to take roles as one-day killers of sisters, daughters, and wives in the name of honor. In addition to this microcausal pathway, the book relies on theories of cultural evolution to explain how honor killing was an adaptation to specific ecological challenges and co-evolved with other patriarchic institutions.
Capitoli di libri sul tema "Root traits and exudation":
1
Rengel, Z. "Genetic control of root exudation". In Food Security in Nutrient-Stressed Environments: Exploiting Plants’ Genetic Capabilities, 215–26. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-017-1570-6_24.
2
Chen, Ying Long, Ivica Djalovic e Zed Rengel. "Phenotyping for Root Traits". In Phenomics in Crop Plants: Trends, Options and Limitations, 101–28. New Delhi: Springer India, 2015. http://dx.doi.org/10.1007/978-81-322-2226-2_8.
3
Katou, Kiyoshi, Takehide Taura e Muneyoshi Furumoto. "A biophysical model for water movement in roots: Root exudation and root pressure". In Structural and Functional Aspects of Transport in Roots, 147–50. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-0891-8_28.
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Sheshshayee, M. S., Ehab Abou-Kheir, Sreevathsa Rohini, Namita Srivastava, B. Mohanraju, Karaba N. Nataraja, T. G. Prasad e M. Udayakumar. "Phenotyping for Root Traits and Their Improvement Through Biotechnological Approaches for Sustaining Crop Productivity". In Root Genomics, 205–32. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-540-85546-0_9.
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Orman, Beata, Aleksander Ligeza, Iwona Szarejko e Miroslaw Maluszynski. "EST-Based Approach for Dissecting Root Architecture in Barley Using Mutant Traits of Other Species". In Root Genomics, 11–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-540-85546-0_2.
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Chimungu, Joseph G., e Jonathan P. Lynch. "Root Traits for Improving Nitrogen Acquisition Efficiency". In Plant Biotechnology, 181–92. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06892-3_15.
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Schneider, Hannah M., e Jonathan P. Lynch. "Root Traits for Improving N Acquisition Efficiency". In Plant Biotechnology, 163–80. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-68345-0_12.
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Heim, A., I. Brunner, B. Frey, E. Frossard e J. Luster. "Aluminium resistance of Norway spruce: Root exudation versus immobilisation in roots". In Plant Nutrition, 450–51. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/0-306-47624-x_217.
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Feil, B., R. Thiraporn, G. Getsler e P. Stamp. "Root traits of maize seedlings—indicators of nitrogen efficiency?" In Genetic Aspects of Plant Mineral Nutrition, 97–101. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-2053-8_15.
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Hinsinger, Philippe, Michael J. Bell, John L. Kovar e Philip J. White. "Rhizosphere Processes and Root Traits Determining the Acquisition of Soil Potassium". In Improving Potassium Recommendations for Agricultural Crops, 99–117. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-59197-7_4.
Abstract (sommario):
AbstractPlants acquire K+ ions from the soil solution, and this small and dynamic pool needs to be quickly replenished via desorption of surface-adsorbed K from clay minerals and organic matter, by release of interlayer K from micaceous clay minerals and micas, or structural K from feldspars. Because of these chemical interactions with soil solid phases, solution K+ concentration is kept low and its mobility is restricted. In response, plants have evolved efficient strategies of root foraging. Root traits related to root system architecture (root angle and branching), root length and growth, together with root hairs and mycorrhiza-related traits help to determine the capacity of plants to cope with the poor mobility of soil K. Rooting depth is also important, given the potentially significant contribution of subsoil K in many soils. Root-induced depletion of K+ shifts the exchange equilibria, enhancing desorption of K, as well as the release of nonexchangeable, interlayer K from minerals in the rhizosphere. Both these pools can be bioavailable if plant roots can take up significant amounts of K at low concentrations in the soil solution (in the micromolar range). In addition, roots can significantly acidify their environment or release large amounts of organic compounds (exudates). These two processes ultimately promote the dissolution of micas and feldspars in the rhizosphere, contributing to the mining strategy evolved by plants. There are thus several root or rhizosphere-related traits (morphological, physiological, or biochemical) that determine the acquisition of K by crop species and genotypes.
Atti di convegni sul tema "Root traits and exudation":
1
Belimov, A. A., A. I. Shaposhnikov, D. S. Syrova, T. S. Azarova, N. M. Makarova, O. S. Yuzikhin e V. I. Safronova. "The effect of microorganisms and heavy metals on the exudation of low molecular weight organic compounds by plant roots". In CURRENT STATE, PROBLEMS AND PROSPECTS OF THE DEVELOPMENT OF AGRARIAN SCIENCE. Federal State Budget Scientific Institution "Research Institute of Agriculture of Crimea", 2020. http://dx.doi.org/10.33952/2542-0720-2020-5-9-10-105.
Abstract (sommario):
The aim of our research was to study the effect of growth-promoting rhizobacteria (Pseudomonas oryzihabitans and Variovorax paradoxus) and toxic elements (Al, Cd and Hg) on the root exudation in various pea (Pisum sativum L.) genotypes. For this, methods of periodic cultures, gnotobiotic plant-microbial systems, ICPE and UPLC were used. It was established that rhizobacteria actively utilized organic acids and sugars secreted by the roots and contributed to an increase in pH and Al immobilization in the rhizosphere. Cadmium increased the exudation of many substances of pea line SGE, but this effect was more pronounced in the mutant SGECdt. Stimulation of the exudation of amino acids was detected during Hg treatment to a greater extent in wild-type SGE. The combined action of Cd and Hg did not lead to a further increase in exudation. The results obtained indicate various mechanisms of exudation of the studied fractions, while the most pronounced differences are observed between the fractions of amino acids or sugars with organic acids. Exudation of organic acids plays an important role in the decreased stability and accumulation of Hg by the pea mutant SGECdt.
2
Belimov, A. A., A. I. Shaposhnikov, D. S. Syrova, P. V. Guro, O. S. Yuzikhin, T. S. Azarova, A. L. Sazanova, G. V. Gladkov, E. A. Sekste e V. I. Safronova. "Response of plants and nitrogen-fixing symbiosis to the toxicity of cadmium and mercury using the pea mutant SGECdt". In 2nd International Scientific Conference "Plants and Microbes: the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.039.
Abstract (sommario):
The combined effect of Hg and Cd on the growth, elemental composition, root exudation and interactions with rhizobia of pea SGE and its mutant SGECdt was studied in hydroponics and sand. The tolerance mechanisms of legume-rhizobia symbiosis to heavy metals are discussed.
3
Kaiser, Christina, Julia Wiesenbauer, Stefan Gorka, Alexander Koenig, Lilian Marchand e Erich Inselsbacher. "Using reverse microdialysis to simulate and explore root exudation ‘hot spots’ in the soil". In Goldschmidt2021. France: European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.8128.
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"The relationship between root exudation, accumulation of heavy metals and symbiotrophy in peas (Pisum sativum L.)". In Plant Genetics, Genomics, Bioinformatics, and Biotechnology. Novosibirsk ICG SB RAS 2021, 2021. http://dx.doi.org/10.18699/plantgen2021-019.
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Mishra, Divya, Sharon Chemweno, Ofer Hadar, Naftali Lazarovitch e Jonathan E. Ephrath. "Deep-learning-based image super-resolution for enhanced root hair visualization and root traits analysis". In Remote Sensing for Agriculture, Ecosystems, and Hydrology XXV, a cura di Christopher M. Neale e Antonino Maltese. SPIE, 2023. http://dx.doi.org/10.1117/12.2687786.
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Singhvi, Ajay, Bo Ma, Johannes Daniel Scharwies, Jose R. Dinneny, Butrus T. Khuri-Yakub e Amin Arbabian. "Non-Contact Thermoacoustic Sensing and Characterization of Plant Root Traits". In 2019 IEEE International Ultrasonics Symposium (IUS). IEEE, 2019. http://dx.doi.org/10.1109/ultsym.2019.8925944.
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"Evaluating Aluminum Toxicity Tolerance in Wheat Cultivars Based on Root Traits". In International Conference On Agriculture, Ecology And Biological Engineering. Universal Researchers, 2015. http://dx.doi.org/10.17758/ur.u0915215.
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Saccomani, Massimo, Piergiorgio Stevanato, Massimo Cagnin, Giampaolo Fama, Marco De Biaggi e Enrico Biancardi. "Genetic diversity for root morpho-physiological traits and productivity in sugar beet". In 33rd Biennial Meeting of American Society of Sugarbeet Technologist. ASSBT, 2005. http://dx.doi.org/10.5274/assbt.2005.54.
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Benkert, Edwin J. "Detecting corn rootworm (Diabroticaspp.) resistance development toBt-RW traits: Root injury vs beetle emergence". In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.115204.
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"THE ROOT FUNGAL MICROBIOME: EVALUATING THE LINK WITH FLORAL TRAITS OF NORTHERN HIGHBUSH BLUEBERRY". In IS-MPMI Congress. IS-MPMI, 2023. http://dx.doi.org/10.1094/ismpmi-2023-45.
Rapporti di organizzazioni sul tema "Root traits and exudation":
1
Phillips, Donald A., Yitzhak Spiegel e Howard Ferris. Optimizing nematode management by defining natural chemical bases of behavior. United States Department of Agriculture, novembre 2006. http://dx.doi.org/10.32747/2006.7587234.bard.
Abstract (sommario):
This project was based on the hypothesis that nematodes interacting with plants as either parasites or beneficial saprophytes are attracted to their host by natural products. This concept was supported by numerous observations that parasitic nematodes are attracted to root exudates. Our overall goal was to identify nematode sensory compounds from root exudates and to use that information for reducing nematicide applications. We applied skills of the investigators to achieve three specific objectives: 1) Identify nematode behavioral cues (e.g., attractants or repellents) in root exudates; 2) Identify new natural nematicidal compounds; and 3) Combine a natural attractant and a nematicide into a nematode trap. Because saprophytic nematodes benefit plants by mineralizing organic matter, we sought compounds attractive primarily to parasitic nematodes. The project was constructed on several complementary foundations. First, data from Dr. Spiegel’s lab showed that under aseptic conditions Ditylenchus dipsaci, a parasite on onion, is attracted to certain fractions of onion root exudates. Second, PI Phillips had a sizeable collection of natural plant products he had identified from previous work on Rhizobium-legume interactions, which could be tested “off the shelf”. Third, Dr. Ferris had access to aseptic and natural populations of various saprophytic and parasitic nematodes. The project focused on five nematode species: D.dipsaci, Heterodera avenae, and Tylenchulussemipenetransat ARO, and Meloidogyne javanicand Caenorhabditis elegans at UCD. Ten pure plant compounds, mostly flavonoids, were tested on the various nematode species using six different assay systems. Results obtained with assorted test systems and by various scientists in the same test systems were essentially irreproducible. Many convincing, Many convincing, i.e. statistically significant, results in one system or with one investigator could not be repeated with other assays or different people. A recent report from others found that these compounds, plus another 30, were inactive as attractants in three additional parasitic nematode species (Wuyts et al. Nematology 8:89- 101, 2006). Assays designed to test the hypothesis that several compounds together are required to attract nematodes have thus far failed to find a reproducibly active combination. In contrast to results using pure plant compounds, complex unfractionated exudates from aseptic onion root reproducibly attracted D. dipsaci in both the ARO and UCD labs. Onion root exudate collection, separation into HPLC fractions, assays using D. dipsaci and MS-MS experiments proceeded collaboratively between ARO and UCD without any definitive identification of an active compound. The final active fraction contained two major molecules and traces of several other compounds. In the end, analytical studies were limited by the amount of onion root exudate and the complexity of the purification process. These tests showed that aseptic plant roots release attractant molecules, but whether nematodes influence that release, as insects trigger release of attractants from plants, is unknown. Related experiments showed that the saprophyte C. elegans stimulates its prey, Pseudomonas bacteria, to increase production of 2, 4-diacetylphloroglucinol (DAPG) a compound that promotes amino acid exudation by plant roots. It is thus possible that saprophytic nematodes are attracted primarily to their bacterial or fungal prey and secondarily to effects of those microorganisms on root exudation. These observations offer promising avenues for understanding root-zone interactions, but no direct routes to controlling nematodes in agriculture were evident. Extracts from two plant sources, Chrysanthemum coronarium and Sequoia sempervirens, showed nematicidal activity at ARO and UCD, respectively. Attempts to purify an active compound from S. sempervirens failed, but preliminary results from C. coronarium are judged to form a potential basis for further work at ARO. These results highlight the problems of studying complex movement patterns in sentient organisms like nematodes and the issues associated with natural product isolation from complex mixtures. Those two difficulties combined with complications now associated with obtaining US visas, slowed and ultimately limited progress on this project. As a result, US investigators expended only 65% of the $207,400 originally planned for this project. The Israeli side of the project advanced more directly toward its scientific goals and lists its expenditures in the customary financial report.
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Bar-Tal, Asher, Paul R. Bloom, Pinchas Fine, C. Edward Clapp, Aviva Hadas, Rodney T. Venterea, Dan Zohar, Dong Chen e Jean-Alex Molina. Effects of soil properties and organic residues management on C sequestration and N losses. United States Department of Agriculture, agosto 2008. http://dx.doi.org/10.32747/2008.7587729.bard.
Abstract (sommario):
Objectives - The overall objective of this proposal was to explore the effects of soil properties and management practices on C sequestration in soils and off-site losses of N.The specific objectives were: 1. to investigate and to quantify the effects of soil properties on C transformations that follow OW decomposition, C losses by gaseous emission, and its sequestration by organic and mineral components of the soil; 2. to investigate and to quantify the effects of soil properties on organic N mineralization and transformations in soil, its losses by leaching and gaseous emission; 3. to investigate and to quantify the effects of management practices and plants root activity and decomposition on C and N transformations; and 4. to upgrade the models NCSOIL and NCSWAP to include inorganic C and root exudation dynamics. The last objective has not been fulfilled due to difficulties in experimentally quantification of the effects of soil inorganic component on root exudation dynamics. Objective 4 was modified to explore the ability of NCSOIL to simulate organic matter decomposition and N transformations in non- and calcareous soils. Background - Rates of decomposition of organic plant residues or organic manures in soil determine the amount of carbon (C), which is mineralized and released as CO₂ versus the amount of C that is retained in soil organic matter (SOM). Decomposition rates also greatly influence the amount of nitrogen (N) which becomes available for plant uptake, is leached from the soil or lost as gaseous emission, versus that which is retained in SOM. Microbial decomposition of residues in soil is strongly influenced by soil management as well as soil chemical and physical properties and also by plant roots via the processes of mineral N uptake, respiration, exudation and decay.
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Nippert, Jesse, Kate McCulloh, Kevin Wilcox, Kim O'Keefe, Rachel Keen e Anping Chen. Using root and soil traits to forecast woody encroachment dynamics in mesic grassland. Office of Scientific and Technical Information (OSTI), dicembre 2023. http://dx.doi.org/10.2172/2248061.
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Aaron Hogan, Aaron Hogan. How do roots vary? An exploration of root functional traits across an environmental gradient in Hainan, China. Experiment, giugno 2017. http://dx.doi.org/10.18258/9485.
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Waisel, Yoav, Bobbie McMichael e Amram Eshel. Decision Making within Plant Root Systems. United States Department of Agriculture, marzo 1996. http://dx.doi.org/10.32747/1996.7613030.bard.
Abstract (sommario):
Architecture of a root system is the expression of the potential of various root types to branch, to grow and to coordinate with other plant organs, under the specific limitations of the environmental conditions. The present investigation has proven the following points. 1) Genotypes with different types of root systems were identified. The growth patterns of their roots and the distribution of laterals along their main axes were recorded. 2) The patterns of development of the root systems of four cotton genotypes, throughout the entire life cycle of the plants, were described, even at such a late stage of development when the total length of the roots exceeded two kilometers. To the best of our knowledge, this is the first time that an analysis of this type is accomplished. 3) The development of root systems under restrictive soil conditions were compared with those that have developed under the non-restrictive conditions of aeroponics. Results indicate that in the absence of the mechanical impedance of the soil, cotton plants develop single roots that reach the length of 6 m, and have a total root length of 2000 m. Thus, root growth is strongly inhibited by the soil, with some root types being inhibited more than others. 4) One of the important decisions, in constructing an operational root system architecture of mature plants, is the shift of the balance between various root fractions in favor of the very fine roots. 5) Root system architecture is determined, in part, by the sites of initiation of the lateral roots. This is determined genetically by the number of xylem archs and by the totuosity of the stele. Selection for such traits should be sought.
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Dubcovsky, Jorge, e T. (Tzion) Fahima. Validation of candidate genes for a QTL responsible for water stress tolerance and their diversity in wheat. Israel: United States-Israel Binational Agricultural Research and Development Fund, 2022. http://dx.doi.org/10.32747/2022.8134149.bard.
Abstract (sommario):
The main goals of this project as stated in the original proposal were to identify which of the candidate gene(s) identified in a 1.5 Mb region of wheat and rye chromosomes 1RS and 1BS were responsible for the differences in root architecture, reveal their natural variation and characterize the epistatic interactions that modulate their effect in different backgrounds. Background: Wheat is an essential crop for global food security and is well adapted to a wide variety of soils. However, the gene networks regulating different wheat root architectures remain poorly understood. Root depth and biomass distribution in the soil profile are critical traits for adaptation to water stress, and a good source for these traits is the introgression of the short arm of rye chromosome one (1RS) into common wheat. A recombinant 1RS chromosome with a small wheat 1BS introgressions and a duplicated 1RS segment (1RW) showed reduced drought tolerance and was used for the identification of the causal genes.
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Kapulnik, Yoram, Maria J. Harrison, Hinanit Koltai e Joseph Hershenhorn. Targeting of Strigolacatones Associated Pathways for Conferring Orobanche Resistant Traits in Tomato and Medicago. United States Department of Agriculture, luglio 2011. http://dx.doi.org/10.32747/2011.7593399.bard.
Abstract (sommario):
This proposal is focused on examination of two plant interactions: parasitic with Orobanche, and symbiosis with arbuscular mycorrhiza fungi (AMF), and the involvement of a newly define plant hormones, strigolactones (SLs), in these plant interactions. In addition to strigolactones role in regulation of above-ground plant architecture, they are also known to be secreted from roots, and to be a signal for seed germination of the parasitic plants Orobanche. Moreover, secreted strigolactones were recognized as inducers of AMFhyphae branching. The present work was aimed at Generation of RNAi mutants of both tomato and Medicago, targeting multiple genes that may be involved in strigolactone production, carotenoid biosynthesis pathway, Pi signaling or other metabolic pathways, and hence affect AMF colonization and/or Orobanche resistance. Following the newly formed and existing RNAi mutants were examined for AMF colonization and Orobanche resistance. At the first phase of this project Orobanche seed germination assays and AMF colonization were examined in intact plants. These assays were shown to be effective and resulted with enhancement of Orobanche seed germination and AMF colonization in WT tomato plants, whereas roots of strigolactones impaired lines did not result with Orobanche seed germination and mycorrhiza colonization. Unexpectedly, root organ cultures (ROC) that were produced from the same wild type (WT) and mutant lines did not induce the Orobanche seed germination and AMFhyphal branching. This implies that under in vitro conditions ROC cultures are missing an important component for induction of Orobanche seed germination and AMFhyphal branching. In another line of experiments we have tested transgenic lines of Medicagotruncatula for AMFhuyphal branching and Orobanche seed germination assays. These lines included lines silenced for a GRAS transcription factor (RNAi 1845), an NBS-LRR type resistance gene (RNAi 1847), a kinase (RNAi 2403) and a protein of unknown function (RNAi 2417). In all cases, five independent transgenic root lines showed altered AMFphenotypes with reduced or aberrant colonization patterns. Following, we transformed tomato plants with the M. truncatulaTC 127050 PhosphoinositidekinaseRNAi construct. Transgenic lines that contained GUS constructs were used as control. All transgenic lines showed reduced level of Orobanche seed germination, masking any strigoalctones-specific effect. The research demonstrated that SLs production may not be examined in ROC –based bioassays. It was shown by the 3 independent assays employed in this project that none of the recognized characters of SLs may be reflected in these bioassays. However, when the whole plant root exudates were examined, SLs activity in root exudates was demonstrated. Hence, it can be concluded that the presence of an intact shoot, and possibly, shoot factors, may be necessary for production of SLs in roots. Another point of interest that rises from these results is that the presence of SLs is not necessary for AMF completion of life cycle. Hence, it may be concluded that SLs are important for AMFhyphal branching, before symbiosis, but not essential for AMF colonization and life cycle completion under ROC system conditions.
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Minz, Dror, Stefan J. Green, Noa Sela, Yitzhak Hadar, Janet Jansson e Steven Lindow. Soil and rhizosphere microbiome response to treated waste water irrigation. United States Department of Agriculture, gennaio 2013. http://dx.doi.org/10.32747/2013.7598153.bard.
Abstract (sommario):
Research objectives : Identify genetic potential and community structure of soil and rhizosphere microbial community structure as affected by treated wastewater (TWW) irrigation. This objective was achieved through the examination soil and rhizosphere microbial communities of plants irrigated with fresh water (FW) and TWW. Genomic DNA extracted from soil and rhizosphere samples (Minz laboratory) was processed for DNA-based shotgun metagenome sequencing (Green laboratory). High-throughput bioinformatics was performed to compare both taxonomic and functional gene (and pathway) differences between sample types (treatment and location). Identify metabolic pathways induced or repressed by TWW irrigation. To accomplish this objective, shotgun metatranscriptome (RNA-based) sequencing was performed. Expressed genes and pathways were compared to identify significantly differentially expressed features between rhizosphere communities of plants irrigated with FW and TWW. Identify microbial gene functions and pathways affected by TWW irrigation*. To accomplish this objective, we will perform a metaproteome comparison between rhizosphere communities of plants irrigated with FW and TWW and selected soil microbial activities. Integration and evaluation of microbial community function in relation to its structure and genetic potential, and to infer the in situ physiology and function of microbial communities in soil and rhizospere under FW and TWW irrigation regimes. This objective is ongoing due to the need for extensive bioinformatics analysis. As a result of the capabilities of the new PI, we have also been characterizing the transcriptome of the plant roots as affected by the TWW irrigation and comparing the function of the plants to that of the microbiome. *This original objective was not achieved in the course of this study due to technical issues, especially the need to replace the American PIs during the project. However, the fact we were able to analyze more than one plant system as a result of the abilities of the new American PI strengthened the power of the conclusions derived from studies for the 1ˢᵗ and 2ⁿᵈ objectives. Background: As the world population grows, more urban waste is discharged to the environment, and fresh water sources are being polluted. Developing and industrial countries are increasing the use of wastewater and treated wastewater (TWW) for agriculture practice, thus turning the waste product into a valuable resource. Wastewater supplies a year- round reliable source of nutrient-rich water. Despite continuing enhancements in TWW quality, TWW irrigation can still result in unexplained and undesirable effects on crops. In part, these undesirable effects may be attributed to, among other factors, to the effects of TWW on the plant microbiome. Previous studies, including our own, have presented the TWW effect on soil microbial activity and community composition. To the best of our knowledge, however, no comprehensive study yet has been conducted on the microbial population associated BARD Report - Project 4662 Page 2 of 16 BARD Report - Project 4662 Page 3 of 16 with plant roots irrigated with TWW – a critical information gap. In this work, we characterize the effect of TWW irrigation on root-associated microbial community structure and function by using the most innovative tools available in analyzing bacterial community- a combination of microbial marker gene amplicon sequencing, microbial shotunmetagenomics (DNA-based total community and gene content characterization), microbial metatranscriptomics (RNA-based total community and gene content characterization), and plant host transcriptome response. At the core of this research, a mesocosm experiment was conducted to study and characterize the effect of TWW irrigation on tomato and lettuce plants. A focus of this study was on the plant roots, their associated microbial communities, and on the functional activities of plant root-associated microbial communities. We have found that TWW irrigation changes both the soil and root microbial community composition, and that the shift in the plant root microbiome associated with different irrigation was as significant as the changes caused by the plant host or soil type. The change in microbial community structure was accompanied by changes in the microbial community-wide functional potential (i.e., gene content of the entire microbial community, as determined through shotgun metagenome sequencing). The relative abundance of many genes was significantly different in TWW irrigated root microbiome relative to FW-irrigated root microbial communities. For example, the relative abundance of genes encoding for transporters increased in TWW-irrigated roots increased relative to FW-irrigated roots. Similarly, the relative abundance of genes linked to potassium efflux, respiratory systems and nitrogen metabolism were elevated in TWW irrigated roots when compared to FW-irrigated roots. The increased relative abundance of denitrifying genes in TWW systems relative FW systems, suggests that TWW-irrigated roots are more anaerobic compare to FW irrigated root. These gene functional data are consistent with geochemical measurements made from these systems. Specifically, the TWW irrigated soils had higher pH, total organic compound (TOC), sodium, potassium and electric conductivity values in comparison to FW soils. Thus, the root microbiome genetic functional potential can be correlated with pH, TOC and EC values and these factors must take part in the shaping the root microbiome. The expressed functions, as found by the metatranscriptome analysis, revealed many genes that increase in TWW-irrigated plant root microbial population relative to those in the FW-irrigated plants. The most substantial (and significant) were sodium-proton antiporters and Na(+)-translocatingNADH-quinoneoxidoreductase (NQR). The latter protein uses the cell respiratory machinery to harness redox force and convert the energy for efflux of sodium. As the roots and their microbiomes are exposed to the same environmental conditions, it was previously hypothesized that understanding the soil and rhizospheremicrobiome response will shed light on natural processes in these niches. This study demonstrate how newly available tools can better define complex processes and their downstream consequences, such as irrigation with water from different qualities, and to identify primary cues sensed by the plant host irrigated with TWW. From an agricultural perspective, many common practices are complicated processes with many ‘moving parts’, and are hard to characterize and predict. Multiple edaphic and microbial factors are involved, and these can react to many environmental cues. These complex systems are in turn affected by plant growth and exudation, and associated features such as irrigation, fertilization and use of pesticides. However, the combination of shotgun metagenomics, microbial shotgun metatranscriptomics, plant transcriptomics, and physical measurement of soil characteristics provides a mechanism for integrating data from highly complex agricultural systems to eventually provide for plant physiological response prediction and monitoring. BARD Report
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Cytryn, Eddie, Mark R. Liles e Omer Frenkel. Mining multidrug-resistant desert soil bacteria for biocontrol activity and biologically-active compounds. United States Department of Agriculture, gennaio 2014. http://dx.doi.org/10.32747/2014.7598174.bard.
Abstract (sommario):
Control of agro-associated pathogens is becoming increasingly difficult due to increased resistance and mounting restrictions on chemical pesticides and antibiotics. Likewise, in veterinary and human environments, there is increasing resistance of pathogens to currently available antibiotics requiring discovery of novel antibiotic compounds. These drawbacks necessitate discovery and application of microorganisms that can be used as biocontrol agents (BCAs) and the isolation of novel biologically-active compounds. This highly-synergistic one year project implemented an innovative pipeline aimed at detecting BCAs and associated biologically-active compounds, which included: (A) isolation of multidrug-resistant desert soil bacteria and root-associated bacteria from medicinal plants; (B) invitro screening of bacterial isolates against known plant, animal and human pathogens; (C) nextgeneration sequencing of isolates that displayed antagonistic activity against at least one of the model pathogens and (D) in-planta screening of promising BCAs in a model bean-Sclerotiumrolfsii system. The BCA genome data were examined for presence of: i) secondary metabolite encoding genes potentially linked to the anti-pathogenic activity of the isolates; and ii) rhizosphere competence-associated genes, associated with the capacity of microorganisms to successfully inhabit plant roots, and a prerequisite for the success of a soil amended BCA. Altogether, 56 phylogenetically-diverse isolates with bioactivity against bacterial, oomycete and fungal plant pathogens were identified. These strains were sent to Auburn University where bioassays against a panel of animal and human pathogens (including multi-drug resistant pathogenic strains such as A. baumannii 3806) were conducted. Nineteen isolates that showed substantial antagonistic activity against at least one of the screened pathogens were sequenced, assembled and subjected to bioinformatics analyses aimed at identifying secondary metabolite-encoding and rhizosphere competence-associated genes. The genome size of the bacteria ranged from 3.77 to 9.85 Mbp. All of the genomes were characterized by a plethora of secondary metabolite encoding genes including non-ribosomal peptide synthase, polyketidesynthases, lantipeptides, bacteriocins, terpenes and siderophores. While some of these genes were highly similar to documented genes, many were unique and therefore may encode for novel antagonistic compounds. Comparative genomic analysis of root-associated isolates with similar strains not isolated from root environments revealed genes encoding for several rhizospherecompetence- associated traits including urea utilization, chitin degradation, plant cell polymerdegradation, biofilm formation, mechanisms for iron, phosphorus and sulfur acquisition and antibiotic resistance. Our labs are currently writing a continuation of this feasibility study that proposes a unique pipeline for the detection of BCAs and biopesticides that can be used against phytopathogens. It will combine i) metabolomic screening of strains from our collection that contain unique secondary metabolite-encoding genes, in order to isolate novel antimicrobial compounds; ii) model plant-based experiments to assess the antagonistic capacities of selected BCAs toward selected phytopathogens; and iii) an innovative next-generation-sequencing based method to monitor the relative abundance and distribution of selected BCAs in field experiments in order to assess their persistence in natural agro-environments. We believe that this integrated approach will enable development of novel strains and compounds that can be used in large-scale operations.
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Savaldi-Goldstein, Sigal, e Todd C. Mockler. Precise Mapping of Growth Hormone Effects by Cell-Specific Gene Activation Response. United States Department of Agriculture, dicembre 2012. http://dx.doi.org/10.32747/2012.7699849.bard.
Abstract (sommario):
Plant yield largely depends on a complex interplay and feedback mechanisms of distinct hormonal pathways. Over the past decade great progress has been made in elucidating the global molecular mechanisms by which each hormone is produced and perceived. However, our knowledge of how interactions between hormonal pathways are spatially and temporally regulated remains rudimentary. For example, we have demonstrated that although the BR receptor BRI1 is widely expressed, the perception of BRs in epidermal cells is sufficient to control whole-organ growth. Supported by additional recent works, it is apparent that hormones are acting in selected cells of the plant body to regulate organ growth, and furthermore, that local cell-cell communication is an important mechanism. In this proposal our goals were to identify the global profile of translated genes in response to BR stimulation and depletion in specific tissues in Arabidopsis; determine the spatio-temporal dependency of BR response on auxin transport and signaling and construct an interactive public website that will provide an integrated analysis of the data set. Our technology incorporated cell-specific polysome isolation and sequencing using the Solexa technology. In the first aim, we generated and confirmed the specificity of novel transgenic lines expressing tagged ribosomal protein in various cell types in the Arabidopsis primary root. We next crossed these lines to lines with targeted expression of BRI1 in the bri1 background. All lines were treated with BRs for two time points. The RNA-seq of their corresponding immunopurified polysomal RNA is nearly completed and the bioinformatic analysis of the data set will be completed this year. Followed, we will construct an interactive public website (our third aim). In the second aim we started revealing how spatio-temporalBR activity impinges on auxin transport in the Arabidopsis primary root. We discovered the unexpected role of BRs in controlling the expression of specific auxin efflux carriers, post-transcriptionally (Hacham et al, 2012). We also showed that this regulation depends on the specific expression of BRI1 in the epidermis. This complex and long term effect of BRs on auxin transport led us to focus on high resolution analysis of the BR signaling per se. Taking together, our ongoing collaboration and synergistic expertise (hormone action and plant development (IL) and whole-genome scale data analysis (US)) enabled the establishment of a powerful system that will tell us how distinct cell types respond to local and systemic BR signal. BR research is of special agriculture importance since BR application and BR genetic modification have been shown to significantly increase crop yield and to play an important role in plant thermotolerance. Hence, our integrated dataset is valuable for improving crop traits without unwanted impairment of unrelated pathways, for example, establishing semi-dwarf stature to allow increased yield in high planting density, inducing erect leaves for better light capture and consequent biomass increase and plant resistance to abiotic stresses.