Thèses sur le sujet « Tolerance to biotic stress »
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South, Kaylee. « Improving abiotic and biotic stress tolerance in floriculture crops ». The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595499762154056.
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Karim, Sazzad. « Exploring plant tolerance to biotic and abiotic stresses / ». Uppsala : Dept. of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200758.pdf.
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Chilufya, Jedaidah, Kousha Mohensi et Aruna Kilaru. « The Role of Anandamide in Biotic Stress Tolerance in Mosses ». Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etsu-works/4843.
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Mosses are small avascular bryophytes with a haploid dominant gametophyte and a diploid sporophyte stage. The gametophyte cells are single layered and lack a protective cuticle, which is the first line of defense in vascular plants. These factors would render them highly susceptible to stress but on the contrary, mosses have flourished on land for the past 450 million years with tolerance to both abiotic and biotic stress. Occurrence of unique lipids in bryophytes was considered as an adaptive means to survive harsh terrestrial condition. A recent study identified a lipid metabolite, anandamide in the Physcomitrella patens. Anandamide (NAE 20:4) belongs to a group of fatty acid ethanolamides or N –acylethanolamines (NAEs). In eukaryotes, NAEs were shown to play an important role in mediating stress responses. In plants, NAE 14:0 has been implicated in biotic stress response; its levels increased up to 50-fold in elicitor-treated tobacco plants, along with induction of defense gene expression and inhibition of alkalization. In animals anandamide acts as an endocannabinoid ligand and mediates several physiological responses including stress. This study aims to use P. patens as the model system because of its available genomic database and prior studies on biotic stress, to examine if NAE 20:4 contributes to their ability to tolerate biotic stress. It is hypothesized that the occurrence of anandamide will play a role in mediating biotic stress tolerance in P. patens. To test this hypothesis, three specific aims are proposed. They are to determine the effect of 1) elicitor-treatment on NAE and fatty acid profile in the moss, 2) anandamide on elicitor-induced morphological and physiological changes in the moss and 3) anandamide on elicitor-induced defense gene expression in moss. Mosses utilize similar defense mechanisms as flowering plants and disease symptoms can easily be studied using microscopy because of their haploid dominant gametophyte stage with monolayer cells. The induction of defense gene expression will be studied by quantitative PCR and changes in lipid profile by selective lipidomics. This study is expected to provide novel insights into the role of anandamide in early land plants, specifically in response to biotic stress.
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Muthevhuli, Mpho. « Investigation of the role of AtNOGC1, a guanylyl cyclase protein in response to abiotic and biotic stress ». University of the Western Cape, 2018. http://hdl.handle.net/11394/6763.
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>Magister Scientiae - MScAgricultural production is one of the most important sectors which provide food for the growing world population which is estimated to reach 9.7 billion by 2050, thus there is a need to produce more food. Climate change, on the other hand, is negatively affecting major global crops such as maize, sorghum, wheat and barley. Environmental factors such as salinity, drought, high temperatures and pathogens affect plant production by oxidatively damaging the physiological processes in plants, leading to plant death. Poor irrigation used to combat drought result in salinasation, which is estimated to affect 50% of arable land by 2050. Plants have developed several mechanisms that protect them against stress and these include overexpression of stress responsive genes and altered signal transduction to change the expression of stress responsive genes, among others. Cyclic 3’5’ guanosine monophosphate (cGMP), a second messenger that is synthesised by guanylyl cyclase (GC), transmit signals to various cellular functions in plants during plant development, growth and response to abiotic and biotic stresses. Arabidopsis thaliana nitric oxide guanylyl cyclase 1 (AtNOGC1) is a guanylyl cyclase which upon activation by nitric oxide (NO) leads to the production of more cGMP. Cyclic GMP further activates protein kinases, ion gated channels and phosphodiesterase which mediate response to various stresses. In this project the role of AtNOGC1 was investigated in response to abiotic and biotic stresses through analysis of its evolutionary relationships, promoter, gene expression and functional analysis via the viability assays in Escherichia coli (E.coli). Phylogenetic tree, exon-intron structure and conserved motifs were analysed using the Molecular Evolutionary Genetics Analysis (MEGA V.7), Gene Structure Display Server 2.0 (GSDS 2.0), and Multiple Expectation Maximisation for Motif Elicitation (MEME) tools respectively. AtNOGC1’s gene expression was analysed by the Real-Time Quantitative Reverse Transcription Polymerase Reaction (qRT-PCR), whereas functional analysis was carried out using the cell viability (liquid and spot) assays to determine its ability to confer stress tolerance to E. coli.
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Sarkar, Jayanwita. « Temperature stress in wheat plants, its alleviation by selected plant growth promoting rhizobacteria and comparative evaluation of their role in tolerance to biotic stress ». Thesis, University of North Bengal, 2018. http://ir.nbu.ac.in/handle/123456789/2656.
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Lo, Cicero Luca. « Generation of CsGSTUs over-expressing tobacco plants and their role in abiotic and biotic stress tolerance ». Doctoral thesis, Università di Catania, 2014. http://hdl.handle.net/10761/1574.
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Xenobiotics are toxic chemicals that are normally not the natural substrates for enzymes or transporters involved in plant resistance. Plants have developed a three phases detoxification system from toxic compounds. Xenobiotic are firstly activated so that certain functional groups can be exposed to the successive action of several modifying enzymes. Among them, the glutathione transferases (GSTs) catalyze the nucleophilic addition of glutathione (GSH) to the electrophilic groups of a large variety of hydrophobic toxic molecules. Previously, two gstu genes have been isolated from sweet orange leaves [(Citrus sinensis) L. Osbeck)] namely GSTU1 and GSTU2. The encoded proteins differ in three amino acids, all of them included in the C-terminal domain of the enzymes (R89P, E117K, I172V). In order to evaluate the contribution of the mismatched amino acids on the catalytic activity of enzymes, several cross-mutant genes were produced by site-directed mutagenesis followed by the biochemical characterization of the in vitro expressed enzymes. In this work, transgenic tobacco plants via Agrobacterium tumefaciens mediated transformation over-expressing both the wild type and mutant CsGSTU genes were generated. Along with the molecular characterization of transformed plants, an in planta study to assess their ability in detoxifying herbicides was also performed. Therefore, transgenic plants were subjected to the action of fluorodifen, a diphenyl ether herbicide that cause photooxidative stress by inhibition of the plastid protoporphyrinogen oxidase and alachlor a chloroacetanilide herbicide which is used to control the growth of broad-leafed weeds and grasses in many crops. The electrolytic leakage assay was carried out to test the damage caused by fluorodifen treatment upon transformed and untransformed tobacco plants. The data revealed that the transgenic lines show a sharp reduction of membrane damage compared with the wild type tobacco plants. To study the tolerance towards alachlor in planta, we assayed the growth inhibition of untrasformed wild type and transgenic tobacco seedlings in the presence of 7.5 mg/l of alachlor. Alachlor negatively influences the growth of roots and stems of untransformed an transformed tobacco seedlings with the exception of the transgenic plants over-expressing CsGSTU2 which are clearly unaffected by herbicide treatment considering either stem or root lenght. Consequently, the herbicide-tolerant transgenic tobacco plants, which are described in the present study, can be utilized for phytoremediation of residual xenobiotics in the environment. Drought and salinity stress tolerance was also assessed. When exposed to 200 mM NaCl both the wild type and transgenic seedlings exhibit a reduction of root lenght, with the exception of the CsGSTU2 over-expressing tobacco line whose root length is as long as untreated control roots indicating a high level of tolerance to NaCl. The effect of drought stress upon root elongation was measured by growing seedlings in the presence of 8% mannitol. In this case all treated tobacco seedlings disclose a sharp decrease of root length, although transgenic lines appear to better tolerate drought stress conditions as the mean root length is significantly higher than that of treated tobacco wild type seedlings. In order to understand the response of tobacco plants over-expressing the CsGSTU genes to biotic stress, untransformed and transformed tobacco leaves were infiltrated with a bacterial suspension of the P. syringae pv. tabaci Tox+ DAPPG-PG 676 strain. The differences observed in symptomatology indicate that the over-expression of CsGSTU1 and CsGSTU2 in tobacco plant bestow the capability to avoid active toxin diffusion in plant tissues blocking chlorotic halos formation probably because tabtoxin is head towards a modification pathway in which CsGSTs could be involved in. This result was confirmed when tobacco leaves was treated with culture filtrates.
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Rouifed, Soraya. « Bases scientifiques pour un contrôle des renouées asiatiques : performances du complexe hybride Fallopia en réponse aux contraintes environnementales ». Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10006.
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La croissance d'une plante est un processus dynamique qui répond aux différentes caractéristiques de l'environnement. La baisse de production de biomasse induite par les différents stress, les perturbations ou la compétition détermine la tolérance des plantes à ces contraintes. Dans le cas d'une plante invasive, caractériser cette tolérance est crucial pour déterminer les habitats sensibles et rechercher des moyens de prévention ou de lutte. Les taxa du genre Fallopia sont ici étudiés dans le cadre de l'invasion du département de la Loire. Leurs réponses au stress nutritif, salin, et à une perturbation sont associées aux conditions environnementales favorisant ou limitant l'invasion. Les résultats obtenus apportent des éléments de réflexion sur les mécanismes à l'origine de l'invasion par les renouées et sur l'efficience de différentes méthodes de lutte et de prévention de l'invasionPlant growth is a dynamic process that responds to environmental characteristics. The decrease of the plant biomass production induced by various stresses, disturbance, or competition, determines the tolerance to these constraints. In the case of invasive plants, assessing this tolerance is crucial to determine invasibility and to find prevention or control methods. The taxa of the genus Fallopia are here considered in the context of the invasion of the Loire department. Their responses to nutrient stress, salt stress, and disturbance are associated with environmental conditions favouring or limiting the invasion. The results give some evidences about mechanisms implied in the success of Fallopia spp and about the effectiveness of different prevention or control methods
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Escalante, Pérez María. « Poplar responses to biotic and abiotic stress ». kostenfrei, 2009. http://nbn-resolving.de/urn/resolver.pl?urn=nbn:de:bvb:20-opus-46893.
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Madeo, M. « MEDICINAL PLANT RESPONSE TO ABIOTIC AND BIOTIC STRESS ». Doctoral thesis, Università degli Studi di Milano, 2010. http://hdl.handle.net/2434/150114.
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Medicinal plants have always been considered a rich source of secondary metabolites that promote human health. Quality and property of medicinal plants strictly depend on secondary metabolites profile. They also play important roles in plant physiological processes and in ecological systems. The environment exerts a selective pressure on plants and these molecules actively participate to the plant response and adaptation. Amongst secondary metabolite, the phenolic compounds possess properties able to prevent oxidative stress. Therefore, an enhancement of the amount of phenolic compounds can be observed under different environmental factors.
With this project we aimed to study the phenolic compounds of the medicinal plant Achillea collina Becker ex Rchb. cv “SPAK”, and their implication in physiological and biochemical response to abiotic and biotic stresses. We seek the possibility to increase the synthesis of phenolics with health properties or useful as potential control agents of insect pests.
Abiotic stress. Hydroponic culture was used to evaluate the effect of long-term mineral, nitrogen starvation (abiotic stress) in A. collina. By means of HPLC-DAD-ESI/MS and NMR techniques, the content and the qualitative profile of A. collina methanol soluble phenolics, were evaluated. We concluded that the methanol extracts of A. collina leaves and roots are rich in hydroxycinnamic acids such as chlorogenic acid (2.33 ± 0.3 mg g-1 Dw), 3,5-di-O-caffeoylquinic acid (10.7 ± 4.2 mg g-1 Dw) and 4,5-di-O-caffeoylquinic acid (0.88 ± 0.24 mg g-1 Dw). The content of hydroxycinnamic acids significantly increased in plants growth under mineral nitrogen starvation, respect to the control plants. Chlorogenic acid increased by 2.5 and 3-fold and 3,5-di-O-caffeoylquinic acid increased by 8.5 and 35-fold in leaves and root, respectively.
Biotic stress. A. collina plants cultivated in soil were infested with the phloem feeders aphids. We set up the system (e.g., age of plant, type of the cage, number of insects per plant, duration of infestation) to co-cultivated the plants with specialist (Macrosiphoniella millefolii) and generalist (Myzus persicae Sulzer) aphids. Plant growth, water and total protein content were evaluated. Based on a preliminary assessment of phenolic fingerprint, further extractions and separations were performed on A. collina leaves, to obtained soluble and cell wall-bound fractions and their sub-classes. Our results showed that A. collina plants were strongly affected by aphid infestation. Twenty days after infestation, the fresh weight was twenty-fold and seven-fold increased, in control and infested plants. Water and protein content, condensed tannins and methanol soluble phenolics content, were not affected by the aphid infestation. Cell wall-bound phenolics content increased in infested plants. The main phenolics were found to be chlorogenic acid and 3,5-di-O-caffeoylquinic in methanol soluble fraction, and caffeic acid in cell wall fraction. The chromatographic profiles showed that the main hydroxycinnamic acids were present in control and in both M. persicae and M. millefolli infested plants. The quantitative analysis indicated that the levels of chlorogenic acid and 3,5-di-O-caffeoylquinic acid, were 44% and 37% higher in M. persicae infested plants, respectively. The levels of chlorogenic acid and 3,5-di-O-caffeoylquinic acid, were 27% and 39% higher in M. millefolli infested plants, respectively. Twenty days after infestation the content of caffeic acid was resulted 43% and 34% higher in M. persicae and M. millefolli infested plants, respectively. These differences should indicate the different evolutionary interaction between plant and generalist/specialist aphid. We hypotheses that the increase of these molecules may represent a plant resistance mechanism against aphid attack. Finally, a chemometric approach, by means multivariate statistical analysis, was applied on chromatogram profiles to verify whether there is difference between methanol soluble fraction of infested and non infested A. collina plants. The discriminant analysis showed a significant effect of phloem feeders aphids on soluble phenolic compounds and indicated two peaks, not yet identified, that separate control from infested plants.
In conclusion the model system developed to cultivate A. collina was useful to understand the metabolic basis of the environment interactions. The main hydroxycinnamic acids identified, were resulted increased in both abiotic and biotic stress, suggesting their implication in A. collina protection to environmental controversies.
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Capra, E. « PROTEIN EXPRESSION PROFILING ASSOCIATED TO BIOTIC STRESS IN MAIZE ». Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/168732.
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Plant biotic stresses are caused by pathogens, parasites, predators and their outcome results from interaction between, host, pathogen and environment. Pathogens attack could be due by several organisms as fungi, bacteria, viruses oomycetes, nematodes and insects that cause specific and systemic response. Two of the major pests affecting maize crop in Lombardy region are Fusarium verticillioides fungus and the Diabrotica virgifera virgifera LeConte insect. The etiology of two diseases is strictly interdependent, plant fungus infection is often deriving after kernel injuries by wounding or insect attack.
F. veritillioides infection typically occurs on kernels, with a high level of fungal infection and micotoxin contamination. In resistant inbred maize genotype, kernel showed significant decrease of infection incidence, with limited amounts of total fumonisin content and reduced fungal growth.
We attempt to identify protein involved in Fusarium resistance by protein profile resistant and susceptible lines. We found only two protein peaks at 5.79 and 14.96 Kda that were commonly expressed in the susceptible lines but no specific protein of interest were present in kernel from resistance lines. Only the susceptible line CO354, showed variation in the Late Embryogenesis Abundant LEA3 protein, previously described as protein associated to fungal resistance in maize.
D. virgifera attack is prevalentely due by direct larvae infestation and damage to the maize root system. Plants respond to insect infestation by emitting volatile compounds among which the sequiterpene (E)-β-caryophillene that attracts natural enthomopathogenic nematodes. This volatile compound has been found in response to herbivore damage in several wild relatives of maize and in cultivated maize lines from European breeding programs but not in most lines from the North American breeding program. In order to understand mechanisms involved in defence response, maize lines that differ in (E)-β-caryophillene synthase expression were characterized by protein profiling and tps23 gene expression. We found that maize responds to methyl jasmonate treatment and D. virgifera infestation similarly by inducing the tps23 gene, but the jasmonate mediated response differs quantitative and temporary in different maize lines. Methyl jasmonate treatment induce also the expression of other three proteins i.e. actin-depolymerizing factor 3 ADF3, nucleotide pyrophosphatase/phosphodiesterase NPP and anionic peroxidase probably involved in maize herbivore insect response.
Proteomic characterization of maize lines differing in response to pathogen attack may be a useful approach to better understand mechanisms involved in plant pathogen response and to find new markers associated to biotic stress response. The potential uses of these biomarkers in assisted breeding program however remain still under investigation.
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Khan, Asif Ali. « Breeding maize for stress tolerance ». Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366240.
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Alzwiy, Ibrahim A. Mohamed. « The interaction between abiotic and biotic stress in Arabidopsis thaliana ». Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/13946.
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Plants are continuously exposed to different abiotic and biotic stresses in their natural environment. Their capacity to survive depends on the capacity to perceive external signal and quality amount a defence response for protection from the stress perceived. The purpose of this project was to study the impact of combined abiotic stress and biotic stress on the outcome of the disease inducing Arabidopsis thaliana – Pseudomonas syringae interaction. This study included a focus on the role of ABA in these interactions and also whether 3´-O-β D- ribofuranosyl adenosine (hereafter it called ‘400’ compound), a novel adenosine derived compound induced during compatible interactions, was involved. The later involved the targetted disruption of a putative 400 biosynthetic pathway involving analysis of knockout mutants of enzymes; APD-ribose diphosphatase NAD binding / hydrolases of the NUDIX class, glucosyl transferases, ribosyltransferases, a ribose-phosphate pyrophosphokinase3 and galactosyltransferases. Unfortunately, none of these targeted interventions modified the host response to Pseudomonas infection, nor altered levels of 400 in challenged leaves. The primary research investigated the interaction between abiotic and biotic stresses in Arabidopsis plants focussing on the modulation of plant defence against multiple, and possibly antagonistic, stress responses and the role plant hormones play in this process. We showed that high light caused enhanced susceptibility to the already virulent Pseudomonas syringae DC3000pvsp61. The pathways contributing to this enhanced susceptibility were largely ABA independent. Subsequent characterization of transgenic lines expressing the soluble Arabidopsis abscisic acid receptors, PYRABACTIN RESISTANCE1-LIKE4-6 provided compelling evidence for a role for these receptors in DC3000 virulence strategies, but they contribute to a lesser extent to the enhanced susceptibility under high light. This was corroborated genetically by using mutants of the immediately downstream targets of PYLs, the type two protein phosphatase, specifically the triple mutant hab1-1/abi2-1/abi1-2. A number of epitope and fluorescent constructs were generated to facilitate future studies of the role of ABA signaling. Targetted profiling suggested that SA dynamics were altered under DC3000 challenged Arabidopsis grown under high light. Furthermore, differential accumulation of flavonoids suggested these may also play a role in attenuating host defences under high light. Finally we provide evidence based on comparative analysis of that the photoreceptors phytochrome double mutant phyA-211/phyB-9 and cry1/cry2 behave antagonistically in Arabidopsis response to DC3000. Overall our studies support the conclusion that plants abiotic stress (HL) response takes precedence over biotic stress (DC3000) responses and that abiotic stress is detrimental to plant immunity. The luciferase transgenic PYL lines showed high level of expression of ClucP::PYL5 plant tissues challenged 2hpi of DC3000 (OD600: 0.15) in comparison with C1lucP::PYL6. This result opposes to what RT-PCR reported; which was that three PYLs genes display similar expression level at 6hpi of hrpA or 18hpi of DC3000. The epitope tags of CaMV::HA transgenic plants showed HA-tagged signal with stunted phenotype in a range of PYL4, 5 and 6 plants but none of the plants displayed any differences in susceptibility to DC3000. Although, RT-PCR assay showed high levels of expression in the three PYLs, 6hpi of hrpA but no signal was detected in B8eGFP::PYL5 transgenic line either followed the DC3000 and hrpA infection or by examined plant seedlings at early stages under confocal microscopy.
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Nalam, Vamsi J. « 9-Lipoxygenase Oxylipin Pathway in Plant Response to Biotic Stress ». Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115127/.
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The activity of plant 9-lipoxygenases (LOXs) influences the outcome of Arabidopsis thaliana interaction with pathogen and insects. Evidence provided here indicates that in Arabidopsis, 9-LOXs facilitate infestation by Myzus persicae, commonly known as the green peach aphid (GPA), a sap-sucking insect, and infection by the fungal pathogen Fusarium graminearum. in comparison to the wild-type plant, lox5 mutants, which are deficient in a 9-lipoxygenase, GPA population was smaller and the insect spent less time feeding from sieve elements and xylem, thus resulting in reduced water content and fecundity of GPA. LOX5 expression is induced rapidly in roots of GPA-infested plants. This increase in LOX5 expression is paralleled by an increase in LOX5-synthesized oxylipins in the root and petiole exudates of GPA-infested plants. Micrografting experiments demonstrated that GPA population size was smaller on plants in which the roots were of the lox5 mutant genotype. Exogenous treatment of lox5 mutant roots with 9-hydroxyoctadecanoic acid restored water content and population size of GPA on lox5 mutants. Together, these results suggest that LOX5 genotype in roots is critical for facilitating insect infestation of Arabidopsis. in Arabidopsis, 9-LOX function is also required for facilitating infection by F. graminearum, which is a leading cause of Fusarium head blight (FHB) disease in wheat and other small grain crops. Loss of LOX1 and LOX5 function resulted in enhanced resistance to F. graminearum infection. Similarly in wheat, RNA interference mediated silencing of the 9-LOX homolog TaLpx1, resulted in enhanced resistance to F. graminearum. Experiments in Arabidopsis indicate that 9-LOXs promote susceptibility to this fungus by suppressing the activation of salicylic acid-mediated defense responses that are important for basal resistance to this fungus. the lox1 and lox5 mutants were also compromised for systemic acquired resistance (SAR), an inducible defense mechanism that is systemically activated throughout a plant in response to a localized infection. the lox1 and lox5 mutants exhibited reduced cell death and delayed hypersensitive response when challenged with an avirulent strain of the bacterial pathogen Pseudomonas syringae pv tomato. LOX1 and LOX5 functions were further required for the synthesis as well as perception of a SAR-inducing activity present in petiole exudates collected from wild-type avirulent pathogen-challenged leaves. Taken together, results presented here demonstrate that 9-LOX contribute to host susceptibility as well as defense against different biotic stressors.
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Pham, Jasmine. « The role of AHK5 in abiotic and biotic stress signalling ». Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/8959.
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In Arabidopsis thaliana, eight histidine kinases (HKs) have been identified which function in hormone signalling, stimuli perception, and plant development. To better elucidate HK roles in signalling, the function of the least characterised HK, AHK5, in stress tolerance was investigated using a T-DNA insertion knockout line (ahk5-1). Reduced inhibition of seedling root growth was seen in ahk5-1 in response to salinity when compared to wild-type Col-0 in tissue culture assays. In mature plants, ahk5-1 showed greater fresh weight gain under either salinity or drought stress. Loss of AHK5 function did not alter cold stress tolerance, nor basal and acquired heat stress tolerance in terms of seedling root elongation. Infection with the biotrophic pathogen Pseudomonas syringae pv. tomato DC3000 revealed ahk5-1 is compromised in disease resistance, exhibiting increased chlorosis and in planta bacterial growth. Levels of the plant hormones salicylic acid, jasmonic acid, and abscisic acid, alongside the bacterial phytotoxin coronatine, were lower in pathogen challenged ahk5-1 mutants compared to wild-type plants. The ahk5-1 mutant was also more susceptible to the necrotrophic pathogen Botrytis cinerea, supporting more fungal growth and displaying accelerated symptom development. Hydrogen peroxide production has been linked with both resistance and susceptibility towards B. cinerea; in ahk5-1, 3,3-diaminobenzidene (DAB) staining suggested reduced hydrogen peroxide production in response to infection. Complementation and expression of AHK5 with either full-length genomic AHK5 under the 35S CaMV promoter or full-length AHK5 cDNA under the native promoter rescued the ahk5-1 mutant stress response phenotypes. In summary, AHK5 was found to negatively regulate abiotic stress tolerance whilst positively contributing towards resistance against pathogens employing different lifestyles. To begin to establish an AHK5 signalling network, tandem affinity purification coupled with LC-MS/MS was employed for identification of possible AHK5 interacting proteins. Suggestions for further optimisation of the purification method are presented. The role of AHK5 in regulation of plant stress responses through modulation of reactive oxygen species and hormone signalling and through protein-protein interactions are reviewed. Suggestions for further investigation are also discussed.
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Endeshaw, Solomon Tadesse. « Grape and olive : physiological responses to biotic and abiotic stress ». Doctoral thesis, Università Politecnica delle Marche, 2013. http://hdl.handle.net/11566/242716.
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Le piante crescono in ambiente aperto in continuo cambiamento e sono sottoposte a stress. Gli stress possono essere classificati come interni e esterni. Lo stress interno porta a mutazioni o a abnormi divisioni cellulari e infine a una ripartizione anomala della crescita, dell’allocazione e della ripartizione del carbonio. Stress esterni possono essere abiotici o biotici. Siccità, freddo, caldo, alta salinità, fitotossine rilasciate da lettiere indecomposte o altri residui organici sono fra i fattori che più drasticamente riducono la crescita, lo sviluppo e la produzione delle piante. Fra gli stress biotici quelli da patogeni (batteri, funghi, fitoplasmi, virus) sono i più pericolosi per la produzione. Nei prossimi anni per consentire livelli elevati di produzione capaci di rispondere alla crescente domanda di olio e vino, ogni regione produttiva dovrà rispondere con un incremento delle superfici coltivate nelle zone agroecologiche in cui sono attualmente coltivate oppure dovrà espandersi in nuove zone. Questo richiederà in ogni caso un cambiamento di tecniche di coltivazione e di gestione degli impianti che dovranno di conseguenza fronteggiare maggiori stress biotici (nelle zone meno vocate) o stress dovuti al reimpianto (se impiantati negli stessi appezzamenti).
Questo progetto ha lo scopo di valutare la risposta fisiologica della vite e dell’olivo a stress biotici e abiotici. In particolare sono oggetto stati di studio gli effetti del legno nero (fitoplasma) e del accartocciamento virale (GLRaV-3 virus) sugli scambi gassosi e sulla produzione di vite Chardonnay and Cabernet Franc, rispettivamente. Sono stati inoltre approfonditi gli effetti di residui colturali di olivo indecomposti e di sansa proveniente da un frantoio a due fasi su olivo cv. Arbequina and Frantoio. L’infezione con fitoplasmi e virus ha indotto una riduzione significativa della fotosintesi, della traspirazione e della conduttanza stomatica in entrambi i vitigni durante l’estate dopo
l’allegagione. La riduzione degli scambi gassosi e del metabolismo ha indotto una riduzione della produzione, della crescita dei tralci e della loro lignificazione. In definitiva la riduzione della produzione è stata pari al 70 e 40% rispettivamente. L’applicazione di residui colturali di olivo e di sanse di olivo su piante in vaso ha ridotto la crescita radicale e dei germogli in funzione della dose applicata, mentre ha portato in proporzione ad un aumento del contenuto di sostanza organica nel substrato.
In conclusione, nel caso di fitoplasmi e virus è necessaria un’attenta profilassi per evitare la diffusione attraverso il materiale di vivaio e una volta presenti in campo deve essere prevista una campagna di eradicazione delle piante infette che possono sopravvivere all’infezione e funzionare da inoculo. Nel caso dell’olivo si deve invece tenere conto che applicazioni localizzate di residui indecomposti e di sanse hanno un’azione temporanea fortemente tossica per le radici e quindi per poter sfruttare al meglio il miglioramento indotto del contenuto di sostanza organica e non avere ripercussioni negative sulle produzioni serve un’attenta programmazione delle dosi e del momento dell’intervento.Plants grow and develop in an open field, with continuously changing weather condition that induces stress. Stress are broadly classified as external and internal. Internal stress is that drive from mutation or abnormal cell divisions and to unbalanced growth and carbon allocation and partitioning. External stress can have abiotic and biotic origin. Drought, cold, high-salinity, heat and phytotoxin released from undecomposed litter and manure are major abiotic stresses that severely reduce the plant growth, development and yield. Whereas, pathogen (bacteria, fungi, phytoplasma, virus) are the major biotic stress that severely reduce yield. To meet the current increase in global demand of agricultural good in general and olive oil and wine in particular, each growing region has to respond either by incorporating new olive and grape orchard in the existing agroecological zone and/or expanding to new agroecological zones or by changing mode of cultivation and orchard management, facing different biotic stress and external stress in replanting condition. This project aimed at evaluating the physiological responses of grape and olive to biotic and abiotic stress respectively. In particular, effect of Bios noir (BN, a phytoplama disease) and grapevine leafroll associated virus 3 (GLRaV-3, viral disease) on gas exchange and yield of Vitis vinifera cv. Chardonnay and Cabernet Franc respectively; and effect of undecomposed olive shoot residue (OSR, originated from pruning and leaf shedding) and fresh two-phase olive mill waste (TPOMW, coming from two-phase decanter) were studied on shoot growth, root proliferation and biomass partition of Olea eropaea L. cv. Arbequina and Frantoio. Biotic stress originated from BN and GLRAV-3 infection showed that Photosynthesis, stomatal conductance and transpiration were significantly reduced in the symptomatic Chardonnay and Cabernet Franc vines through the summer after the fruit set. The reduction in metabolism due to BN and GLRaV-3 infection in cv. Chardonnay and Cabernet Franc had a direct influence on the decrease in total berry production, vine size and cane lignifications of symptomativ vines. Indeed, they suffered a drastic decrease of about 70 and 40% in yield respectively. Whereas, application of OSR and TPOMW in the pot altered shoot and root growth, biomass partition and relative growth rate of fine root and shoot; while increasing soil total organic matter and carbon, total N and polyphenol content of the growing substrate. Hence there is no chemical spray develop to control the infection of BN and GLRaV-3 pathogens, planting phytoplasma and virus free root stocks during the vineyard establishment and uprooting the infected vine and replanting new to avoid spread during pruning and by insect vectors is the best way to minimize the adverse effect of BN and GLRaV-3 on quality and quantity yield. To avoid antagonistic effect of OSR and TPOMW on root and shoot growth and improve soil fertility knowing the exact quantity, for each types olive orchards, and when to apply in play major role.
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Alexandre, Ana Isabel Pereira. « Temperature stress tolerance in chickpea rhizobia ». Doctoral thesis, Universidade de Évora, 2010. http://hdl.handle.net/10174/11582.
Texte intégralRésumé :
The aims of the present thesis were to study the chickpea rhizobia diversity and biogeography using Portugal as case study; to evaluate the temperature stress tolerance of the isolates, and to investigate the molecular basis of stress tolerance. The phylogenetic performance of the co-chaperone dnaJ was also addressed, in order to find an altemative marker to 16S rRNA gene. According to the 16S rRNA gene phylogeny, most isolates were found to be distinct from the typical chickpea rhizobia species, Mesorhizobium cíceri and M. mediterraneum. Some provinces of origin are associated with particular species groups. dnaJ was found to be a Useful phylogenetic marker for Mesorhizobium and for the Alphaproteobactería class. The evaluation of temperature stress tolerance revealed tolerant and sensitive isolates to both
heat and cold. Analysis of the expression of dnaK and groESL chaperone genes suggested that higher induction of these genes is related to higher tolerance to heat. ### - Resumo - A presente tese teve como objectivos o estudo da diversidade e biogeografia de rizóbio de grão-de-bico em Portugal, a avaliação da tolerância dos rizóbios ao stress térmico, bem
como o estudo das bases moleculares da tolerância ao stress. Estudou-se, ainda, o gene da co-chaperone dnaJ do ponto de vista filogenético.
A filogenia baseada no gene 16S rRNA revelou que a maior parte dos rizóbios de grão-de-bico agrupam com outras espécies, que não as típicas desta leguminosa (Mesorhizobium cicerí e M. mediterraneum). Encontrou-se uma associação entre algumas províncias e determinadas espécies de rizóbio. O gene dnaJ revelou-se um bom marcador filogenético para Mesorhizobium, bem como para a classe Alphaproteobactería. A avaliação da tolerância à temperatura permitiu diferenciar isolados tolerantes e sensíveis, a altas e baixas temperaturas. A análise da expressão dos genes dnaK e groESL, sugeriu que uma maior indução destes genes está relacionada com maior tolerância a altas temperaturas.
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RICCI, SARA. « Study of biotic and abiotic stresses in Solanaceae by metabolic and proteomic approaches ». Doctoral thesis, Università di Foggia, 2017. http://hdl.handle.net/11369/363315.
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Ford, Tiiu Kirsti 1972. « Biotic Factors and Temperature Tolerances via Critical Thermal Methodology in Goldfish ». Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc279125/.
Texte intégralRésumé :
CTMinimum and CTMaximum were measured in 620 goldfish to determine if biotic factors, in particular starvation, condition factor and size, affect temperature tolerance. Twenty-eight days of starvation adversely affected both upper and lower temperature tolerance. Condition factor was related to upper but not lower temperature tolerance.
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Imeh-Nathaniel, Adebobola. « Evolutionary Ecology of Arabidopsis thaliana : Interactions with Biotic and Abiotic Environmental Factors ». Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1351039606.
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Paralkar, Urvi Pradeep. « RELATIONSHIP BETWEEN TOLERANCE OF AMBIGUITY, TOLERANCE OF UNCERTAINTY, AND COPING WITH ACADEMIC STRESS ». OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2522.
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Bernardo, Letizia. « IDENTIFICATION AND CHARACTERIZATION OF PROTEINS INVOLVED IN BIOTIC STRESS RESISTANCE OF CEREALS ». Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3426966.
Texte intégralRésumé :
Leaf rust is one of the most important diseases of barley (Hordeum vulgare) and is caused by the biotrophic fungal pathogen Puccinia hordei. The rust fungi penetrate barley leaves through stomata and colonize cells of the mesophyll, then growing systemically through the leaf vascular tissue.
The leaf rust resistance gene Rph15 is of outstanding interest for resistance breeding because it confers resistance to over 350 Puccinia hordei isolates collected from around the world (Weerasena et al. 2004).
Plant-pathogen interactions activate many cellular signalling processes and, most likely, changes on protein accumulation and phosphorylation pattern of proteins play a pivotal role in plant responses to biotic stress. In this work, a proteomic approach was undertaken to study changes in total proteins accumulation and protein phosphorylation pattern in response to the leaf rust pathogen infection in two barley near isogenic lines, Bowman and Rph15, which differ for the introgression of the leaf rust resistance gene Rph15. Two infection time points, 24 hours and four days, were considered for the analysis.
No statistically significant differences were identified at the early time point, 24 hours post infection, for total and phosphorylated proteins.
At four days after inoculation, total protein analysis led to the identification of twenty-one protein spots significantly up or down regulated with a fold-change equal or higher than two following pathogen infection. Most of down-regulated proteins were found in the Rph15 near-isogenic line while no significantly differential protein abundance was recovered in the susceptible line. Nineteen out of 21 protein spots were characterized by LC-MS/MS analysis and found to be involved in photosynthesis, sugar metabolism, energy balance and defence.
Phosphoproteomics analysis was performed at four day after inoculation. A phosphoprotein enrichment methodology based on MOAC (metal oxide affinity chromatography) was optimized for subsequent 2DE analyses.La ruggine fogliare è una delle malattie più importanti della coltura dell'orzo (Hordeum vulgare) ed è causata dal patogeno fungino biotrofo Puccinia hordei. Il fungo penetra attraverso gli stomi delle foglie dell’orzo e colonizza le cellule del mesofillo, crescendo poi per via sistemica nei tessuti vascolari della foglia. Il gene Rph15 di orzo è di considerevole importanza per il miglioramento genetico della resistenza in quanto conferisce resistenza a più di 350 isolati di P. hordei provenienti da tutto il mondo (Weerasena et al. 2004). L’interazione pianta-patogeno attiva numerosi processi di signalling cellulare e, molto probabilmente, l’accumulo delle proteine e i cambiamenti nel pattern di fosforilazione delle proteine giocano un ruolo centrale nella risposta della pianta in seguito a stress biotico. In questo lavoro, un approccio di tipo proteomico è stato intrapreso per studiare i cambiamenti nei pattern proteici totali e delle proteine fosforilate in seguito a risposta alla ruggine fogliare in due linee quasi isogeniche di orzo, Bowman e la linea Rph15, che differiscono per l’ introgressione del gene Rph15. Due tempi di infezione, 24 ore e quattro giorni, sono stati presi in considerazione per le analisi. Nessuna differenza statisticamente significativa è stata individuate nel primo tempo di infezione precoce, a 24 ore dopo l’inoculo, sia per quanto riguarda le proteine totali che per le proteine fosforilate. A 4 giorni dall’infezione, l’ analisi delle proteine totali ha consentito di identificare ventuno spot proteici significativamente up o down regolati in risposta all’ infezione con un fold-change almeno di 2. La maggior parte delle proteine down-regolate sono state trovate nel campione infettato della linea isogenica contenente il gene di resistenza Rph15, mentre non è stata riscontrata alcuna differenza statisticamente significativa nel pattern proteico della linea isogenica suscettibile. Diciannove dei 21 spot proteici sono stati caratterizzati mediante analisi LC-MS/MS e identificati essere implicati in processi come fotosintesi, metabolismo degli zuccheri, bilancio energetico e risposte di difesa. L’analisi del fosfoproteoma è stata condotta a quattro giorni dopo l’inoculo. Una tecnica di arricchimento in fosfoproteine basata su MOAC (cromatografia di affinità mediante ossidi metallici) che è stata ottimizzata per la successiva analisi 2DE.
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Dutta, Sampa. « Abiotic and biotic stress response of tea plants and their biochemical characterization ». Thesis, University of North Bengal, 2000. http://hdl.handle.net/123456789/878.
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Sheen, Tamsin, et n/a. « Osmotic and desiccation stress-tolerance of Serratia entomophila ». University of Otago. Department of Microbiology & ; Immunology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20081208.114925.
Texte intégralRésumé :
Serratia entomophila, the causative agent of amber disease, is an endemic bacterium used for the biocontrol of New Zealand grass grub larvae. Although the available biopesticide is effective, its use is limited to areas where sub-surface application is feasible, and is also impacted by soil conditions such as moisture levels and osmolarity. The aim of this study was to elucidate the responses of S. entomophila to osmotic and desiccation stresses in relation to challenges encountered during production, storage and soil application, with the goal of developing a more robust and versatile biocontrol agent.
RpoS is a key factor in the stress response of many enteric bacteria. In order to dissociate the effect of RpoS from subsequent cellular stress studies, an rpoS mutant was constructed by site-directed mutagenesis. Assessment of the rpoS mutant showed that RpoS was not implicated in NaC1 or desiccation tolerance of S. entomophila. The rpoS mutant was instead found to have enhanced salt tolerance and could be distinguished from the wild-type by the ability to ferment arabinose, a phenotype that was confirmed through complementation. Complete abolition of the amber disease process was observed using an rpoS strain also missing the Sep virulence genes, suggesting that RpoS is a regulator of the S. entomophila anti-feeding prophage (Afp). These findings indicate a subtle interplay between NaC1 tolerance, virulence and RpoS-mediated regulation of amber disease in S. entomophila.
A transposon mutagenesis screen was carried out to identify genes associated with NaC1 tolerance in S. entomophila. Fourteen mutants displaying NaC1 sensitivity were identified, two of which had mutations in genes with potential implications for the formulation of the bacterium as a biocontrol agent. The gene leuO that encodes a LysR-family transcriptional regulator was found to be essential for S. entomophila NaC1 tolerance. The toxicity of increased cellular LeuO from an over-expression vector led to the investigation of the effects of leuO mutation on the proteome. Multiple protein changes observed by two-dimensional gel analysis suggested that LeuO may be a global regulator in S. entomophila, as has been hypothesised for Salmonella species. A second NaC1-sensitive mutant contained an insertion in afp15, the product of which is thought to be involved in assembly of the Afp. As well as being sensitive to NaC1, the afp15 mutant was unable to induce the anti-feeding component of amber disease, again highlighting the link between stress tolerance and virulence in S. entomophila.
This study also determined that pre-exposure to NaC1 in conjunction with the provision of exogenous glycine betaine significantly enhanced the survival of S. entomophila either in a desiccated state or after application to soil, regardless of the soil moisture content. The implication of this finding on the future formulation of S. entomophila led to investigation of the underlying genetic mechanisms involved in glycine betaine synthesis and NaC1 tolerance. The genes involved in glycine betaine biosynthesis from choline were identified through genomic comparison, degenerate PCR and primer walking. A 6.5 kb region was sequenced and found to contain four genes with homology and similar chromosomal arrangement to the E. coli bet genes (betTIBA). The S. entomophila betIBA genes comprised an operon, flanked by the divergently-transcribed betT gene whose product is responsible for choline transport. To ascertain the relative transcription levels of components of the bet operon, quantitative RT-PCR was performed. Results of qRT-PCR showed that choline in conjunction with NaC1 induced the greatest levels of bet gene transcription, and that levels of the betA transcript were significantly lower than those of the other bet genes. Examination of the betA 5� non-coding region identified a previously undetected hairpin region, possibly accounting for the observed decrease in betA transcript levels.
The findings of this study have significantly advanced our understanding of how S. entomophiia responds to stress, and will contribute to the development of formulation strategies for the production of a robust product capable of application to pasture by a range of teclmiques. In addition, there is significant potential to utilise these findings in the development of other bacterial inocula for a range of biotechnological applications.
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Akhtar, Lal Hussain. « Tissue culture and stress tolerance in Gossypium species ». Thesis, Bangor University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296184.
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Howden, Reuben. « Tolerance to orthostatic stress and human cardiovascular control ». Thesis, De Montfort University, 2002. http://hdl.handle.net/2086/4812.
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Ahmed, Helal Uddin. « Mapping stress tolerance genetic loci in Arabidopsis thaliana ». Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246628.
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Falkenberg, Nyland Ray. « Remote sensing for site-specific management of biotic and abiotic stress in cotton ». Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/478.
Texte intégralRésumé :
This study evaluated the applicability of remote sensing instrumentation for site- specific management of abiotic and biotic stress on cotton grown under a center pivot. Three different irrigation regimes (100%, 75%, and 50% ETc) were imposed on a cotton field to 1) monitor canopy temperatures of cotton with infrared thermometers (IRTs) in order to pinpoint areas of biotic and abiotic stress, 2) compare aerial infrared photography to IRTs mounted on center pivots to correlate areas of biotic and abiotic stress, and 3) relate yield to canopy temperatures. Pivot-mounted IRTs and IR camera were able to differentiate water stress between the irrigation regimes, however, only the IR camera was effectively able to distinguish between biotic (cotton root rot) and abiotic (drought) stress with the assistance of groundtruthing. The 50% ETc regime had significantly higher canopy temperatures, which were reflected in significantly lower lint yields when compared to the 75% and 100% ETc regimes. Deficit irrigation up to 75% ETc had no impact on yield, indicating that water savings were possible without yield depletion.
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VAN, ZELLER DE MACEDO BASTO GONÇALVES MARIA ISABEL. « ROLE OF STILBENES AS A RESISTANCE FACTOR OF THE GRAPEVINE TOWARDS BIOTIC STRESS ». Doctoral thesis, Università Cattolica del Sacro Cuore, 2010. http://hdl.handle.net/10280/775.
Texte intégralRésumé :
La vite è in grado di attivare meccanismi di difesa in risposta a stress biotici e abiotici producendo principalmente metaboliti secondari tra i quali composti stilbenici. Questi composti, detti anche fitoalessine, hanno una azione benefica e riconosciuta sulla salute umana.
Una delle malattie che apporta più danni in tutto il mondo viticolo è la peronospora, causata dal patogeno Plasmopara viticola L, questa tesi ha lo scopo di confrontare le risposte di diverse varietà e cloni attaccate da questo patogeno. Sono state utilizzate foglie e bacche di 10 cloni di Cabernet Sauvignon per verificare l’andamento dell’infezione e la produzione degli stilbeni nel tempo.
Stessa procedura è stata applicata su foglie giovani e vecchie delle varietà di Müller-Thurgau, Chardonnay, Sangiovese, Pinot noir, Cabernet Sauvignon e Solaris. Queste sono state monitorate per verificare l’andamento dell’infezione, la produzione degli stilbeni e l’attivazione della stilbene sintasi.
I risultati delle prove condotte hanno evidenziato differenze tra le varietà e tra i cloni e, soprattutto, tra i diversi organi studiati.The grapevine is able to activate a defence mechanism whenever it interacts with biotic or abiotic stress, mainly by producing defence substances as the stilbenic compounds, phytoalexins known for their health related influence. Combining this fact and the knowledge that the Plasmopara viticola Berk et Curtis, the causal agent of downy mildew, causes considerable damages worldwide to Vitis vinifera L. production during its life cycle, this thesis aims to explore the differences that several grapevine varieties and clones display when confronted with this pathogen. The leaves and small berries of 10 different clones of Cabernet Sauvignon were used to asses infection time course and stilbenic production overtime. Likewise, young and old leaves of the varieties Müller-Thurgau, Chardonnay, Sangiovese, Pinot noir, Cabernet Sauvignon and Solaris, ordered in assumed increasing resistance, were used to assess infection time course, stilbene production on the leaves and the activation of a stilbene synthase gene. All trials conducted highlighted not only the differences within grapevine varieties and grapevine clones but most importantly between the studied grapevine organs.
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VAN, ZELLER DE MACEDO BASTO GONÇALVES MARIA ISABEL. « ROLE OF STILBENES AS A RESISTANCE FACTOR OF THE GRAPEVINE TOWARDS BIOTIC STRESS ». Doctoral thesis, Università Cattolica del Sacro Cuore, 2010. http://hdl.handle.net/10280/775.
Texte intégralRésumé :
La vite è in grado di attivare meccanismi di difesa in risposta a stress biotici e abiotici producendo principalmente metaboliti secondari tra i quali composti stilbenici. Questi composti, detti anche fitoalessine, hanno una azione benefica e riconosciuta sulla salute umana.
Una delle malattie che apporta più danni in tutto il mondo viticolo è la peronospora, causata dal patogeno Plasmopara viticola L, questa tesi ha lo scopo di confrontare le risposte di diverse varietà e cloni attaccate da questo patogeno. Sono state utilizzate foglie e bacche di 10 cloni di Cabernet Sauvignon per verificare l’andamento dell’infezione e la produzione degli stilbeni nel tempo.
Stessa procedura è stata applicata su foglie giovani e vecchie delle varietà di Müller-Thurgau, Chardonnay, Sangiovese, Pinot noir, Cabernet Sauvignon e Solaris. Queste sono state monitorate per verificare l’andamento dell’infezione, la produzione degli stilbeni e l’attivazione della stilbene sintasi.
I risultati delle prove condotte hanno evidenziato differenze tra le varietà e tra i cloni e, soprattutto, tra i diversi organi studiati.The grapevine is able to activate a defence mechanism whenever it interacts with biotic or abiotic stress, mainly by producing defence substances as the stilbenic compounds, phytoalexins known for their health related influence. Combining this fact and the knowledge that the Plasmopara viticola Berk et Curtis, the causal agent of downy mildew, causes considerable damages worldwide to Vitis vinifera L. production during its life cycle, this thesis aims to explore the differences that several grapevine varieties and clones display when confronted with this pathogen. The leaves and small berries of 10 different clones of Cabernet Sauvignon were used to asses infection time course and stilbenic production overtime. Likewise, young and old leaves of the varieties Müller-Thurgau, Chardonnay, Sangiovese, Pinot noir, Cabernet Sauvignon and Solaris, ordered in assumed increasing resistance, were used to assess infection time course, stilbene production on the leaves and the activation of a stilbene synthase gene. All trials conducted highlighted not only the differences within grapevine varieties and grapevine clones but most importantly between the studied grapevine organs.
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BALAN, Bipin. « INVESTIGATION OF BIOTIC STRESS RESPONSES IN FRUIT TREE CROPS USING META-ANALYTICAL TECHNIQUES ». Doctoral thesis, Università degli Studi di Palermo, 2020. http://hdl.handle.net/10447/400369.
Texte intégralRésumé :
In recent years, RNA sequencing and analysis using Next Generation Sequencing (NGS) methods have enabled to understand the gene expression pertaining to plant biotic and abiotic stress conditions in both quantitative and qualitative manner. The large number of transcriptomic works published in plants requires more meta-analysis studies that would identify common and specific features in relation of the high number of objective studies performed at different developmental and environmental conditions. Meta-analysis of transcriptomic data will identify commonalities and differences between differentially regulated gene lists and will allow screen which genes are key players in gene-gene and protein-protein interaction networks. These analyses will allow delivering important information on how a specific environmental factor affects plant molecular responses and how plants activate general stress responses to environmental stresses. The identification of common genes between different biotic stress will allow to gain insight into these general responses and help the diagnosis of an early “stress state” of the plants. These analyses help in monitoring stressed plants to start early specific management procedures for each disease or disorder. In this meta-analysis study, I considered all transcriptomic data related to biotic stresses in fruit tree crops, which are already published. The aim was to determine which genes, pathways, gene set categories and predicted protein-protein interaction networks may play key roles in specific responses to pathogen infections.
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Patankar, A. G. « Biochemical and molecular analysis of the defense mechanism in chickpea against biotic stress ». Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2000. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2289.
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Neudeck, Michelle Joan. « Tolerance of Planktothrix agardhii to nitrogen depletion ». Bowling Green State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1522329471601801.
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MACHADO, VERONICA MIQUELIN. « EFFECT OF ELASTIC-PLASTIC STRESS IN THE DEFECT TOLERANCE UNDER STRESS CORROSION CRACKING ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33679@1.
Texte intégralRésumé :
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Corrosão sob tensão (SCC), que consiste na iniciação e propagação de trincas devido ao efeito combinado de tensões mecânicas e o ambiente corrosivo, é um dano potencial para estruturas e componentes. Além do mais, SCC pode ser explicado por diferentes mecanismos dependendo do par material ambiente corrosivo considerado, o que dificulta o uso de um modelo geral para predizer o comportamento de trincas em SCC. Sendo assim, projetos frequentemente utilizam um critério conservativo que desqualifica materiais susceptíveis à SCC sem analisar de maneira apropriada a influência dos campos de tensão que a induzem. O objetivo deste trabalho é avaliar o efeito de tensões elastoplásticas na corrosão sob tensão. Esta abordagem mecânica considera que todos os efeitos corrosivos envolvidos na corrosão sob tensão podem ser apropriadamente quantificados pelas tradicionais resistências do material à iniciação e propagação de trincas para um ambiente corrosivo específico. Corpos de prova de flexão em Alumínio fragilizados por Gálio líquido serão utilizados para prever o efeito de tensões residuais induzidas por deformações plásticas na iniciação de trincas por corrosão sob tensão. Além disso, uma análise quantitativa baseada no comportamento de trincas não propagantes a partir de entalhes será usada para estimar a tensão necessária para iniciar e propagar trincas em corpos de prova entalhados em aço AISI 4140 sujeitos à corrosão por sulfeto de hidrogênio em ambiente aquoso. O comportamento de trincas curtas e a carga máxima suportada pelos corpos de prova entalhados são analisadas considerando campos de tensões lineares elástico e elastoplásticos através do modelo proposto que será validado através de dados experimentais.
Stress Corrosion Cracking (SCC), which consist in the initiation and propagation of cracks due to the combined attack of mechanical stresses and a corrosive environment is a potential danger for structures and components. Moreover, SCC can be explained by different mechanisms depending on the metal environmental pair, what makes difficult to create a generalized analytical approach to predict the crack behavior in SCC. Therefore, projects often use an over-conservative design criteria that disqualify a material susceptible to SCC without properly evaluate the influence of the stress fields that drive them. The aim of this work is to evaluate the effect of elastic-plastic stress in SCC. This mechanical approach assumes that all chemical effects involved in SCC problems can be appositely described and quantified by traditional material resistances to crack initiation and propagation at under specific environment. Aluminum bending specimens in Gallium environment are used to predict the effect of the residual stress induced by plastic deformation in the crack initiation under SCC conditions. Furthermore, a quantitative analysis based on the non-propagating crack behavior departing from notch tips are used to calculate the necessary stress to initiate and propagate SCC in AISI 4140 steel notched specimens under aqueous hydrogen sulfide environment. The non-propagating crack behavior and the maximum load supported by notched specimens are analyzed under linear elastic and elastic-plastic stress field through the proposed model that will be validated by experimental data.
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Leitão, Susana T. « Unravelling the genetic control of combined biotic/abiotic stress resistance in Phaseolus vulgaris L ». Doctoral thesis, Universidade Nova de Lisboa, Instituto de Tecnologia Química e Biológica António Xavier, 2020. http://hdl.handle.net/10362/95339.
Texte intégralRésumé :
Dissertation presented to obtain the Ph.D degree in Plant Sciences"Common bean (Phaseolus vulgaris L.) is among the most important grain legumes for human consumption worldwide. Portugal has a promising common bean germplasm that resulted from more than five centuries of natural adaptation and farmers’ selection. Nevertheless, limited characterization of this resource hampers its exploitation by breeding programs. To support a more efficient conservation of the national bean germplasm and promote its use in crop improvement, we performed, for the first time, a simultaneous molecular marker and seed and plant morphological characterization of 175 accessions collected from Portuguese mainland and islands traditional bean-growing regions. Most of the Portuguese accessions grouped with the race representatives and wild relatives from the Andean region."
N/A
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Green, Andrew Justin. « Abiotic stress tolerance from the tertiary gene pool of common wheat ». Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32746.
Texte intégralRésumé :
Doctor of PhilosophyDepartment of Agronomy
Allan K. Fritz
Heat and drought stress are two of the most significant abiotic stresses limiting wheat production in the Great Plains and worldwide. Introgression of novel tolerance genes from wild relatives is a strategy which presents promise. This study examined both heat and drought tolerance from the tetraploid species Aegilops geniculata (U[superscript g]U[superscript g]M[superscript g]M[superscript g]). Additional screening for heat tolerance was conducted with the US genome species Aegilops peregrina (Hack) and Aegilops kotschyi (Boiss). A comprehensive screening system for drought tolerance was also constructed to evaluate wheat and its wild relatives. Previous reports suggested that Ae. geniculata accession TA2899 was moderately tolerant to heat stress. It had also previously been used to develop a full set of wheat-Ae. geniculata chromosome addition lines in a Chinese Spring background. To identify the chromosome(s) carrying the heat tolerance, all addition lines, as well as wheat check genotypes, were screened for post-anthesis heat tolerance in two growth chamber experiments. No chromosome addition lines were significantly different (p<0.05) from Chinese Spring, and none were found to have superior performance to the positive check cultivars. Forty-five accessions of Ae. peregrina and its close relative, Ae. kotschyi were screened in a post-anthesis heat experiment. A follow-up experiment compared the genotypes in a split-plot temperature treatment with heat and optimal growth chambers. Many accessions were similar to the control genotypes for grain fill duration, and some exceeded the wheat controls for relative chlorophyll index values on Day 12 and Day 16. TA1889 and TA1904, both Ae. peregrina accessions originating from Israel, had a higher grain fill duration across experiments than the best wheat control, and warrant further investigation. Previous reports suggested drought tolerance in Ae. geniculata. After preliminary screenings, six genotypes were selected for advanced screening and compared with three wheat cultivars. The advanced greenhouse screening system was conducted in 152cm tall PVC growth tubes. The experiment measured multiple plant responses, and had a datalogging system automatically collecting water content and matric potential of the growth media. Multiple accessions warranted further investigation, and showed potentially different modes of drought tolerance, with varying levels of stomatal resistance, biomass, and osmotic adjustment.
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Gass, Thomas Gass Thomas. « Tolerance of soybean to low temperature stress during flowering / ». [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10771.
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Helaly, Alaa el-Din A. « Molecular studies on plants to enhance their stress tolerance ». [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974309494.
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Krell, Andreas. « Salt stress tolerance in the psychrophilic diatom Fragilariopsis cylindrus ». [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980889235.
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Helaly, Alaa El-din A. « Molecular studies on plants to enhance their stress tolerance ». Phd thesis, Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2005/242/.
Texte intégralRésumé :
Environmental stresses such as drought, high salt and low temperature affect plant growth and decrease crop productivity extremely. It is important to improve stress tolerance of the crop plant to increase crop yield under stress conditions. The Arabidopsis thaliana salt tolerance 1 gene (AtSTO1) was originally identified by Lippuner et al., (1996). In this study around 27 members of STO-like proteins were identified in Arabidopsis thaliana, rice and other plant species. The STO proteins have two consensus motifs (CCADEAAL and FCV(L)EDRA). The STO family members can be regarded as a distinct class of C2C2 proteins considering their low sequence similarity to other GATA like proteins and poor conservation in the C-terminus. AtSTO1 was found to be induced by salt, cold and drought in leaves and roots of 4-week-old Arabidopsis thaliana wild-type plants. The expression of AtSTO1 under salt and cold stress was more pronounced in roots than in leaves. The data provided here revealed that the AtSTO1 protein is localized in the nucleus. The observation that AtSTO1 localizes in the nucleus is consistent with its proposed function as a transcription factor. AtSTO1-dependent phenotypes were observed when plant were grown at 50 mM NaCl on agar plates. Leaves of AtSTO1 overexpression lines were bigger with dark green coloration, whereas stunted growth and yellowish leaves were observed in wild-type and RNAi plants. Also, the AtSTO1 overexpression plants when exposed to long-term cold stress had a red leaf coloration which was much stronger than in wild-type and RNAi lines. Growth of AtSTO1 overexpression lines in long term under salt and cold stress was always associated with long roots which was more pronounced than in wild-type and RNAi lines. Proline accumulation increased more strongly in leaves and roots of AtSTO1 overexpression lines than in tissues of wild-type and RNAi lines when treated with 200 mM NaCl, exposed to cold stress or when watering was prevented for one day or two weeks. Also, soluble sugar content increased to higher levels under salt, cold and drought stress in AtSTO1 overexpression lines when compared to wild-type and RNAi lines. The increase in soluble sugar content was detected in AtSTO1 overexpression lines after long-term (2 weeks) growth of plants under these stresses. Anthocyanins accumulated in leaves of AtSTO1 overexpression lines when exposed to long term salt stress (200 mM NaCl for 2 weeks) or to 4°C for 6 and 8 weeks. Also, anthocyanin content was increased in flowers of AtSTO1 overexpression plants kept at 4°C for 8 weeks. Taken together these data indicate that overexpression of AtSTO1 enhances abiotic stress toleranc via a more pronounced accumulation of compatible solutes under stress.
Umweltstress wie zum Beispiel Trockenheit, Salz und niedrige Temperaturen beeinflussen in erheblichem Maße das pflanzliche Wachstum und haben einen negativen Einfluss auf Ertragsleistungen. Untersuchungen zur Verbesserung der Stresstoleranz und des Ernteertrages von Kulturpflanzen sind daher von großer Bedeutung. Pflanzen passen sich Umweltveränderungen durch physiologische und entwicklungsabhängige Prozesse an. In den letzten Jahren wurden zahlreiche Gene identifiziert, die als Reaktion von Umweltstress in der Pflanze aktiviert werden. Salzstress bewirkt negative Veränderungen des pflanzlichen Wasserstatus, die auf veränderte K+/Na+-Verhältnisse und Na+- und Cl--Konzentrationen zurückzuführen sind. Neben Veränderungen in der Bewässerungspraxis spielt heute die Züchtung salztoleranter Pflanzen und die biotechnologische Verbesserung von Kulturpflanzen eine zunehmend wichtige Rolle.
Im Rahmen der Doktorarbeit wurde ein bisher wenig untersuchtes Gen, welches AtSTO1 genannt wird, anhand der Modellpflanze Ackerschmalwand (lat. Arabidopsis thaliana) analysiert. Das Gen wird durch Umweltstress, insbesondere durch Kälte, aktiviert. Es wurden gentechnisch veränderte Pflanzen hergestellt, die eine verstärkte Aktivität des AtSTO1-Gens aufweisen. Diese Pflanzen zeigten bei Vorliegen von hohen Salzkonzentration ein im Vergleich zu unveränderten Pflanzen verbessertes Wachstum. Diese Stimulation des pflanzlichen Wachstums unter Salzstress-Bedingungen war begleitet von einer vermehrten Bildung bestimmter chemischer Substanzen, die die Pflanzen in die Lage versetzen, mit dem Stress besser fertig zu werden. Dazu gehört beispielsweise die Aminosäure Prolin, deren Konzentration in den gentechnisch veränderten Pflanzen nach Stressbehandlung stärker erhöht ist, als in den unveränderten Kontrollpflanzen oder in Pflanzen, die eine reduzierte AtSTO1-Aktivität besaßen. Auch die Gehalte einiger Zucker waren in den gentechnisch modifizierten Pflanzen unter Stress erhöht. Insgesamt hat sich gezeigt, dass AtSTO1 eine wichtige Aufgabe in der Stressantwort spielt. Weitere Untersuchungen sollten es ermöglichen, auch bei Kulturpflanzen, wie etwa Reis, die Stresstoleranz durch Veränderung verwandter Gene zu erhöhen.
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vollständiger Name des Autors: Abdallah Helaly, Alaa El-Din
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Tyrrell, John William. « Stress tolerance of transgenic alfalfa overexpressing glutathione reductase transgenes ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ31872.pdf.
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Ma, Wai-lung, et 馬惠龍. « The role of stress tolerance on marine invasive mussels ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196040.
Texte intégralRésumé :
Marine bioinvasion has been increasing exponentially due to intensive human activities. To manage the threats posed by marine bioinvasion, it is important to understand the key factors for invasion success. Stress tolerance is thought to play an important role in the invasion process, however, little is known of the nature of this tolerance, particularly whether stress tolerance is species- or population-specific. To determine this, laboratory experiments were conducted to investigate differential tolerance of populations of a cosmopolitan marine invasive mussel, Perna viridis, and whether stress tolerance can be altered through pre-selection of individuals. Comparisons were firstly made between two local P. viridis populations from the intertidal and subtidal zones to test if stress tolerance was population-specific. Individuals from the intertidal population had higher baseline heart rates, lower critical salinity values, Scrit, for cardiac activity and longer survival duration at low salinity than individuals from the subtidal population, supporting the presence of population level differences in stress tolerance. Mortality of P. viridis was also compared at sites in both their introduced range (Hong Kong) and native range (Indonesia) which revealed that individuals from the Hong Kong population were more stress tolerant than their native counterparts in Indonesia. Using the same experimental approach, the effect of pre-selection to stress (a prior pre-selection to hypoxia and a subsequent exposure to heat) showed that stress tolerance can be enhanced by pre-selection. The second part of this study investigated whether invasive mussels, Brachidontes variabilis and P. virdis, were more stress tolerant than the native, non-invasive, Septifer virgatus. Laboratory experiments compared the Scrit as well as critical temperature, Hcrit for cardiac activity. Mortality and byssus thread production were also measured in a factorial design with different combinations of temperature (16, 24 and 32 °C) and salinity (8, 16, 32 p.s.u) for 15 days. The two invasive mussels had a higher Hcrit and lower Scrit, which indicated a higher stress tolerance, than the non-invasive mussel. The mortality rate of P. viridis was faster than in B. variabilis and S. virgatus at 8 p.s.u. whereas S. virgatus was the only mussel that exhibited mortality in the medium hyposalinity (16 p.s.u.) and showed much slower byssus attachment than the invasive mussels, suggesting that the invasive mussels are more stress tolerant to heat and medium hyposalinity than the non-invasive species. Overall, stress tolerance proved to be higher in the invasive than non-invasive species and was also population-specific with higher stress tolerance in the invasive population, which may be attributed to the selection of more tolerant individuals during the invasion process. Such a process may occur when founding individuals successfully pass through an invasion process, which may increase the overall mean population-level of stress tolerance and explain why invasive species are generally more stress tolerant than native species. Thus stress tolerance plays an important role in invasion success and invasive species with high stress tolerance may be favoured by climate change, including ocean warming and increased precipitation, which may extend their current distribution range.published_or_final_version
Biological Sciences
Master
Master of Philosophy
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Smith, Hilary April. « Evolution of Reproduction and Stress Tolerance in Brachionid Rotifers ». Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/52145.
Texte intégralRésumé :
Stress can be a driving force for new evolutionary changes leading to local adaptation, or may be responded to with pre-existing, ancestral tolerance mechanisms. Using brachionid rotifers (microzooplankton) as a study system, I demonstrate roles of both conserved physiological mechanisms (heat shock protein induction) and rapid evolution of traits in response to ecologically relevant stressors such as temperature and hydroperiod. Rapid evolution of higher levels of sex and dormancy in cultures mimicking temporary waters represents an eco-evolutionary dynamic, with trait evolution feeding back into effects on ecology (i.e., reduced population growth). I also reveal that prolonged culture in a benign laboratory environment leads to evolution of increased lifespan and fecundity, perhaps due to reduction of extrinsic mortality factors. Potential mechanisms (e.g., hormonal signals) are suggested that may control evolvability of facets of the stress response. Due to prior studies suggesting a role of progesterone signaling in rotifer sex and dormancy, the membrane associated progesterone receptor is assayed as a candidate gene that could show positive selection indicating rapid divergence. Despite some sequence variation that may contribute to functional differences among species, results indicate this hormone receptor is under purifying selection. Detailed analyses of multiple stress responses and their evolution as performed here will be imperative to understanding current patterns of local adaptation and trait-environment correlations. Such research also is key to predicting persistence of species upon introduction to novel habitats and exposure to new stressors (e.g., warming due to climate change). Perhaps one of the most intriguing results of this dissertation is the rapid, adaptive change in levels of sex and dormancy in a metazoan through new mutations or re-arrangements of the genetic material. This suggests species may be able to rapidly evolve tolerance of new stressors, even if standing genetic variation does not currently encompass the suite of alleles necessary for survival.
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Watmough, Shaun A. « Adaptation to pollution stress in trees : metal tolerance traits ». Thesis, Liverpool John Moores University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260825.
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O'Neil, John Daniel. « A molecular investigation of stress tolerance in aspergillus nidulans ». Thesis, University of Wolverhampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273927.
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Jakkamsetty, Chamundeshwari, et Chaitanya Medapudi. « Stress tolerance of encapsulated yeast used for bioethanol production ». Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-9745.
Texte intégralRésumé :
Environmental and economic issues have drawn the world’s attention to produce and utilize energy from renewable sources for sustainable development. One of the attempts includes the production of ethanol from various substrates. Many researchers have focused on utilizing lignocelluloses biomass as substrate for the production of ethanol, which mainly contains cellulose and is a cheap and abundantly available material in the world. One of the major problems faced by researchers during production of ethanol from the lignocellulosic biomass is the stress tolerance of yeast cells, due to the nature of the hydrolysed substrate (lignocellulosic material treated with Nitro methyl cellulose (NMC)). One of the solutions for this problem is to encapsulate the yeast cells. Encapsulation is an attractive method, which can enhance the stress tolerance of the yeast cells in the reactor, and also aid in maintaining a high yeast concentration inside the bioreactor and thereby increase the volumetric productivity of ethanol. This report includes a major study on the sodium chloride and ethanol stress tolerance of alginate chitosan alginate (ACA), alginate chitosan (AC) and APTES treated ACA encapsulated yeast biomass in medium containing different concentrations of glucose under anaerobic conditions. AC capsules shows significant results towards osmotic stress and ethanol stress compared with that of freely suspended cells in stress conditions.AC capsule encapsulated yeast tolerated osmotic stress better than ACA capsules in 2M of NaCl where as freely suspended yeast cells unable to tolerate 2M of NaCl . At 100th hour in AC capsules glucose consumption was 12 g/l where as in ACA capsules glucose consumption at same 100th hour was 2 g/l. At 10% ethanol concentration yeast inside ACA capsules showed 5 g/l of glucose consumption but in freely suspended yeast cells there is no glucose consumption as they cannot tolerate higher stress levels.
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Kuzovkina-Eischen, Yulia A. « Stress Tolerance and Horticultural Evaluation of the Genus Salix ». The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1047496264.
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Peyton, Justin Tyler. « Genomic Platforms and Molecular Physiology of Insect Stress Tolerance ». The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1440175145.
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Brígido, Clarisse Cordeiro. « Tolerance of chickpea mesorhizobia to acid and salt stress ». Doctoral thesis, Universidade de Évora, 2012. http://hdl.handle.net/10174/14546.
Texte intégralRésumé :
The main objectives of this thesis were to evaluate the tolerance of a collection
of native Portuguese chickpea rhizobia to abiotic stresses, namely acidity and
salinity, and to investigate the molecular bases of acidity and salinity tolerance.
Additionally, the evaluation of the symbiotic performance of ACC deaminasetransformed
strains under salinity was performed. The involvement of the
chaperone ClpB in the response to abiotic stresses and in the symbiosis with
chickpea was investigated by gene deletion in a Mesorhizobium strain.
Chickpea rhizobia were assigned to several Mesorhizobium species. In both
stress conditions, tolerant and sensitive rhizobia were found, including
moderately acidophilic isolates. The analysis of the expression of the chaperone
genes dnaK and groESL suggests their involvement in acid tolerance. ACC
deaminase-transformed rhizobia strains showed an improvement of their
symbiotic performance under salinity. The characterization of the ClpB knockout
mutant indicated that ClpB is involved in the nodulation process; RESUMO:Os principais objetivos desta tese foram a avaliação da tolerância a stresses
abióticos, nomeadamente acidez e salinidade, de uma coleção de rizóbios
portugueses nativos de grão-de-bico, e investigar as bases moleculares da
tolerância a ambos os stresses. Adicionalmente, avaliou-se a eficiência
simbiótica de estirpes transformadas com o gene da ACC desaminase em
condições de salinidade. Investigou-se ainda o envolvimento da chaperone
ClpB na resposta a stresses abióticos e na simbiose com grão-de-bico através
da deleção do gene.
Os rizóbios de grão-de-bico pertencem a diferentes espécies de
Mesorhizobium. Encontraram-se rizóbios tolerantes e sensíveis a ambos os
stresses, incluindo isolados moderadamente acidófilos. A análise da expressão
dos genes de chaperones dnaK e groESL sugere o seu envolvimento na
tolerância à acidez. Estirpes de rizóbio transformadas com o gene da ACC
desaminase apresentaram uma melhoria da sua eficiência simbiótica em
condições salinas. A caracterização do mutante ClpB de Mesorhizobium
indicou que esta chaperone está envolvida no processo de nodulação.
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PATEL, VIJAY LAXMAN. « ARABIDOPSIS HSP21 AND MSRB1/MSRB2 IN PLANT STRESS TOLERANCE ». Thesis, The University of Arizona, 2008. http://hdl.handle.net/10150/192201.
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Peththa, Thanthrige Nipuni. « Dissecting the molecular mechanisms of AtBAG4-mediated stress tolerance ». Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/235369/1/Nipuni%2BPeththa%2BThanthrige%2BThesis%283%29.pdf.
Texte intégralRésumé :
Plant biotechnology holds great promise to help meet the supply-demand gaps of agriculture to feed the future population. This thesis investigated the molecular mechanisms of stress tolerance conferred by the Arabidopsis thaliana Bcl-2 associated athanogene 4 (AtBAG4), cytoprotective protein. The research identified a role for AtBAG4 in several plant stress response pathways and further investigated the implications of expressing AtBAG4 in chickpeas. The AtBAG4-chickpea were equivalent to commercially available chickpea in non-stressed conditions but supported improved yields under drought. This knowledge will be used to develop improved chickpea varieties that tolerate stress without yield penalty.