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1
Shen, W.-C., D. R. Stanford e A. K. Hopper. "Loslp, Involved in Yeast Pre-tRNA Splicing, Positively Regulates Members of the SOL Gene Family". Genetics 143, n.º 2 (1 de junho de 1996): 699–712. http://dx.doi.org/10.1093/genetics/143.2.699.
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Abstract To understand the role of Los1p in pre-tRNA splicing, we sought los1 multicopy suppressors. We found SOLl that suppresses both point and null LOS1 mutations. Since, when fused to the Gal4p DNA-binding domain, Los1p activates transcription, we tested whether Los1p regulates SOL1. We found that los1 mutants have depleted levels of SOL1 mRNA and Sollp. Thus, LOS1 appears to positively regulate SOL1. SOL1 belongs to a multigene family with at least two additional members, SOL2 and SOL3. Sol proteins have extensive similarity to an unusual group of glucose-6phosphate dehydrogenases. As the similarities are restricted to areas separate from the catalytic domain, these G6PDs may have more than one function. The SOL family appears to be unessential since cells with a triple disruption of all three SOL genes are viable. SOL gene disruptions negatively affect tRNA-mediated nonsense suppression and the severity increases with the number of mutant SOL genes. However, tRNA levels do not vary with either multicopy SOL genes or with SOL disruptions. Therefore, the Sol proteins affect tRNA expression/function at steps other than transcription or splicing. We propose that LOS1 regulates gene products involved in tRNA expression/function as well as pre-tRNA splicing.
2
May, FE, e JE Ash. "An Assessment of the Allelopathic Potential of Eucalyptus". Australian Journal of Botany 38, n.º 3 (1990): 245. http://dx.doi.org/10.1071/bt9900245.
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Previous studies have shown that various Eucalyptus species can yield allelopathic chemicals which may be effective in suppressing understorey vegetation. However, the techniques employed in many studies do not resemble natural ecological processes. This study used germination of Lolium and growth of Lolium, Lemna, Eucalyptus and Acacia to test for allelopathy. Extraction techniques mimicked typical daily rainfall rates upon quantities of foliage, leaf litter and bark litter that are typically encountered in forests; root leachates were obtained hydroponically; stemflow was obtained following rainfall; soils were leached with water; and volatiles from leaves were studied in an enclosed chamber. Fresh intact leaves caused little growth suppression, in contrast to coarsely chopped leaves and extracted leaf essential oils which were both highly suppressive. Whole leaf litter, shed bark and, especially, stemflow yielded suppressive leachates. Evaporative concentration of leachates in soils was demonstrated, which increased their inhibitory effect. It is apparent that allelopathy must be considered in relation to rainfall and the soil water balance. Decay was shown to reduce the allelopathic effects of leaf and bark litter leachates but some inhibitory chemicals remained after 5 months. It was concluded that allelopathy is likely to be a cause of understorey suppression by Eucalyptus species especially in drier climates.
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Jauri, Patricia Vaz, Nora Altier, Carlos A. Pérez e Linda Kinkel. "Cropping History Effects on Pathogen Suppressive and Signaling Dynamics in Streptomyces Communities". Phytobiomes Journal 2, n.º 1 (janeiro de 2018): 14–23. http://dx.doi.org/10.1094/pbiomes-05-17-0024-r.
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Diseases remain a yield-limiting factor for crops despite the availability of control measures for many pathogens. Indigenous soil microorganisms can suppress some plant pathogens, yet there is little systematic information on the effects of cropping systems on disease-suppressive populations in soil. Streptomyces have been associated with suppression of plant diseases in several naturally occurring disease-suppressive soils. Pathogen-suppressive activity of Streptomyces communities is correlated with higher bacterial densities and with inhibitory phenotypes, driven by competition among indigenous soil bacteria. We sought to characterize relationships between cropping practices and pathogen suppression among soil Streptomyces. We evaluated bacterial and Streptomyces densities and inhibitory activities in soils from a long-term crop rotation experiment. Signaling interactions that altered inhibitory phenotypes among sympatric populations were also evaluated for a subset of samples. Soils from longer rotations, which had a higher number of plant species over time, had larger bacterial and Streptomyces densities, and more inhibitors than soils from shorter rotations. In addition, signaling occurred more frequently among isolates from higher-density communities. Our work shows that bacterial density, pathogen suppression and signaling are interrelated and are affected by crop rotation, suggesting the potential for management to optimize suppressive populations.
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Schlatter, Daniel, Linda Kinkel, Linda Thomashow, David Weller e Timothy Paulitz. "Disease Suppressive Soils: New Insights from the Soil Microbiome". Phytopathology® 107, n.º 11 (novembro de 2017): 1284–97. http://dx.doi.org/10.1094/phyto-03-17-0111-rvw.
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Soils suppressive to soilborne pathogens have been identified worldwide for almost 60 years and attributed mainly to suppressive or antagonistic microorganisms. Rather than identifying, testing and applying potential biocontrol agents in an inundative fashion, research into suppressive soils has attempted to understand how indigenous microbiomes can reduce disease, even in the presence of the pathogen, susceptible host, and favorable environment. Recent advances in next-generation sequencing of microbiomes have provided new tools to reexamine and further characterize the nature of these soils. Two general types of suppression have been described: specific and general suppression, and theories have been developed around these two models. In this review, we will present three examples of currently-studied model systems with features representative of specific and general suppressiveness: suppression to take-all (Gaeumannomyces graminis var. tritici), Rhizoctonia bare patch of wheat (Rhizoctonia solani AG-8), and Streptomyces. To compare and contrast the two models of general versus specific suppression, we propose a number of hypotheses about the nature and ecology of microbial populations and communities of suppressive soils. We outline the potential and limitations of new molecular techniques that can provide novel ways of testing these hypotheses. Finally, we consider how this greater understanding of the phytobiome can facilitate sustainable disease management in agriculture by harnessing the potential of indigenous soil microbes.
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Fernando, Margaret, e Anil Shrestha. "The Potential of Cover Crops for Weed Management: A Sole Tool or Component of an Integrated Weed Management System?" Plants 12, n.º 4 (8 de fevereiro de 2023): 752. http://dx.doi.org/10.3390/plants12040752.
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Cover crops are an important component of integrated weed management programs in annual and perennial cropping systems because of their weed suppressive abilities. They influence weed populations using different mechanisms of plant interaction which can be facilitative or suppressive. However, the question often arises if cover crops can be solely relied upon for weed management or not. In this review we have tried to provide examples to answer this question. The most common methods of weed suppression by an actively growing cover crop include competition for limited plant growth resources that result in reduced weed biomass, seed production, and hence reductions in the addition of seeds to the soil seedbank. Cover crop mulches suppress weeds by reducing weed seedling emergence through allelopathic effects or physical effects of shading. However, there is a great degree of variability in the success or failure of cover crops in suppressing weeds that are influenced by the cover crop species, time of planting, cover crop densities and biomass, time of cover crop termination, the cash crop following in the rotation, and the season associated with several climatic variables. Several studies demonstrated that planting date was important to achieve maximum cover crop biomass, and a mixture of cover crop species was better than single cover crop species to achieve good weed suppression. Most of the studies that have demonstrated success in weed suppression have only shown partial success and not total success in weed suppression. Therefore, cover crops as a sole tool may not be sufficient to reduce weeds and need to be supplemented with other weed management tools. Nevertheless, cover crops are an important component of the toolbox for integrated weed management.
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Ossowicki, Adam, Vittorio Tracanna, Marloes L. C. Petrus, Gilles van Wezel, Jos M. Raaijmakers, Marnix H. Medema e Paolina Garbeva. "Microbial and volatile profiling of soils suppressive to Fusarium culmorum of wheat". Proceedings of the Royal Society B: Biological Sciences 287, n.º 1921 (19 de fevereiro de 2020): 20192527. http://dx.doi.org/10.1098/rspb.2019.2527.
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In disease-suppressive soils, microbiota protect plants from root infections. Bacterial members of this microbiota have been shown to produce specific molecules that mediate this phenotype. To date, however, studies have focused on individual suppressive soils and the degree of natural variability of soil suppressiveness remains unclear. Here, we screened a large collection of field soils for suppressiveness to Fusarium culmorum using wheat ( Triticum aestivum ) as a model host plant. A high variation of disease suppressiveness was observed, with 14% showing a clear suppressive phenotype. The microbiological basis of suppressiveness to F. culmorum was confirmed by gamma sterilization and soil transplantation. Amplicon sequencing revealed diverse bacterial taxonomic compositions and no specific taxa were found exclusively enriched in all suppressive soils. Nonetheless, co-occurrence network analysis revealed that two suppressive soils shared an overrepresented bacterial guild dominated by various Acidobacteria. In addition, our study revealed that volatile emission may contribute to suppression, but not for all suppressive soils. Our study raises new questions regarding the possible mechanistic variability of disease-suppressive phenotypes across physico-chemically different soils. Accordingly, we anticipate that larger-scale soil profiling, along with functional studies, will enable a deeper understanding of disease-suppressive microbiomes.
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Wright, Peter J., Rebekah A. Frampton, Craig Anderson e Duncan Hedderley. "Factors associated with soils suppressive to black scurf of potato caused by Rhizoctonia solani". New Zealand Plant Protection 75 (30 de agosto de 2022): 31–49. http://dx.doi.org/10.30843/nzpp.2022.75.11761.
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Soils in which disease fails to develop despite pathogen presence are considered disease-suppressive. They offer sustainable, effective protection to plants against infection by soil-borne pathogens. Naturally disease-suppressive soils have been reported for diseases of a diverse range of agricultural crops worldwide yet the underlying mechanisms of disease suppression are still not completely understood. Two large greenhouse experiments, conducted during 2017/18 (Year 1) and 2018/19 (Year 2), determined that soils naturally suppressive to stem canker and black scurf of potato (caused by Rhizoctonia solani) are present in vegetable-arable cropping soils of the Auckland and Waikato regions of New Zealand. Soil was pre-treated with heat prior to inoculation with R. solani and compared with untreated and uninoculated controls to ascertain if stem canker and black scurf suppression was ‘general’, or ‘specific’ (i.e. transferable; possibly involving specific microorganisms). Rhizoctonia solani inoculation was also combined with transfer of one part test soil to nine parts of a known disease-conducive soil. Abiotic factors such as soil texture and organic matter content influenced black scurf incidence and severity. Soil microorganisms were also involved in disease suppression since black scurf incidence and severity markedly increased when they were eliminated or reduced by soil heat pre-treatment. Microbial profiling of the soils through sequencing revealed that taxa of geographically close soils of the same type had similar fungal and bacterial community structure and diversity even though they differed in their capacity to suppress black scurf. These results suggest that although the soil microbiome as a whole, was mainly responsible for soil disease suppressiveness, certain bacterial genera or species may play a role in black scurf suppression.
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Sriram, Uma, Jun Xu, Linda Varghese, Heather Bennett, Debra Shivers e Stefania Gallucci. "SOCS molecules are upregulated during IL-4-induced inhibition of Type I interferon responses in murine myeloid dendritic cells. (57.23)". Journal of Immunology 186, n.º 1_Supplement (1 de abril de 2011): 57.23. http://dx.doi.org/10.4049/jimmunol.186.supp.57.23.
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Abstract We have previously reported that IL-4 suppresses the response of murine myeloid dendritic cells (mDCs) to Type I interferons (IFN). We are now investigating the molecular mechanisms of this inhibition in myeloid bone marrow-derived DCs (BMDCs). We have found that sub-optimal doses of IL-4 (down to 0.25ng/mL) can still suppress IFN-a induced gene expression and phosphorylation of STAT1 and STAT2, suggesting that IL-4 acts at the level or upstream of STAT molecules in the Type I IFN signaling pathway. IL-4 suppresses when administered before and also after Type I IFN stimulation and it inhibits the response of DCs to the autocrine IFN-b that is induced upon IFN-a stimulation, acting on its positive feedback loop. The inhibition of protein synthesis by Cyclohexamide (CHX) abrogated the suppressive effects of IL-4 indicating that IL-4 represses Type I IFN signaling through the upregulation of a protein. We then tested the expression of the SOCS molecules as immediate candidates that negatively regulate Type I IFN signaling and are regulated at the transcription level. The gene expression of SOCS-1was highly induced by IL-4 treatment and was synergistically upregulated in the presence of IL-4 and IFN-a; the levels drastically went down when DCs were pretreated with CHX, suggesting that SOCS-1 maybe one of the key players in suppressing the IFN responses. We are currently testing this hypothesis by silencing SOCS-1 expression in DCs.
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Simon, A., e K. Sivasithamparam. "Microbiological differences between soils suppressive and conducive of the saprophytic growth of Gaeumannomyces graminis var. tritici". Canadian Journal of Microbiology 34, n.º 7 (1 de julho de 1988): 860–64. http://dx.doi.org/10.1139/m88-148.
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A soil acidified by ammonium sulphate following annual application of the fertilizer for 9 years was suppressive of the saprophytic growth of Gaeumannomyces graminis var. tritici in soil (pathogen suppressive). The same soil amended with lime was pathogen conducive. In natural field soil microbial respiration and the 'total' number of aerobic microorganisms were greater in the conducive than in the suppressive soil. In a soil-sandwich bioassay of the transferable suppression of saprophytic growth of the pathogen there were higher numbers of 'total' aerobic microorganisms, fluorescent pseudomonads, and Gram-negative organisms, but lower numbers of filamentous fungi and yeasts in the conducive than in the suppressive soil. It was estimated that Trichoderma spp. made up 71 and 34% of the total numbers of fungi counted in the suppressive and conducive soils, respectively. It is proposed that Trichoderma spp. played a major role in the transferable pathogen suppression in the suppressive soil.
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Mazzola, Mark, e Yu-Huan Gu. "Wheat Genotype-Specific Induction of Soil Microbial Communities Suppressive to Disease Incited by Rhizoctonia solani Anastomosis Group (AG)-5 and AG-8". Phytopathology® 92, n.º 12 (dezembro de 2002): 1300–1307. http://dx.doi.org/10.1094/phyto.2002.92.12.1300.
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The induction of disease-suppressive soils in response to specific cropping sequences has been demonstrated for numerous plant-pathogen systems. The role of host genotype in elicitation of the essential transformations in soil microbial community structure that lead to disease suppression has not been fully recognized. Apple orchard soils were planted with three successive 28-day cycles of specific wheat cultivars in the greenhouse prior to infestation with Rhizoctonia solani anastomosis group (AG)-5 or AG-8. Suppressiveness to Rhizoctonia root rot of apple caused by the introduced isolate of R. solani AG-5 was induced in a wheat cultivar-specific manner. Pasteurization of soils after wheat cultivation and prior to pathogen introduction eliminated the disease suppressive potential of the soil. Wheat cultivars that induced disease suppression enhanced populations of specific fluorescent pseudomonad genotypes with antagonistic activity toward R. solani AG-5 and AG-8, but cultivars that did not elicit a disease suppressive soil did not modify the antagonistic capacity of this bacterial community. When soils were infested prior to the initial wheat planting, all cultivars were uniformly susceptible to R. solani AG-8. However, when pathogen inoculum was added after three growth-cycles, wheat root infection during the fourth growth-cycle varied in a cultivar specific manner. The same wheat cultivar-specific response in terms of transformation of the fluorescent pseudomonad community and subsequent suppression of Rhizoctonia root rot of apple was observed in three different orchard soils. These results demonstrate the importance of host genotype in modification of indigenous saprophytic microbial communities and suggest an important role for host genotype in the success of biological control.
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Simon, A., e K. Sivasithamparam. "The soil environment and the suppression of saprophytic growth of Gaeumannomyces graminis var. tritici". Canadian Journal of Microbiology 34, n.º 7 (1 de julho de 1988): 865–70. http://dx.doi.org/10.1139/m88-149.
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The effect of the soil environment on the transferable suppression of the saprophytic growth of Gaeumannomyces graminis var. tritici (pathogen suppression) was studied in a field soil acidified to pH 4.3 by annual treatment with ammonium sulphate for 9 years and in the same soil further amended with a single application of lime (pH 5.4). Pathogen suppression and the activity of Trichoderma spp. were greater when (i) the unlimed (pathogen-suppressive) soil was added at a rate of 1% (w/w) to the same soil treated with γ-radiation than when added at the same rate to the irradiated limed soil; (ii) the limed (pathogen-conducive) soil was added at 1% (w/w) to the irradiated unlimed soil than when added at the same rate to the irradiated limed soil. Pathogen suppression and the activity of Trichoderma spp. were increased in both soils with the addition of an antibacterial agent. The saprophytic growth of G. graminis var. tritici was reduced in the unsterile pathogen-suppressive but not in the pathogen-conducive soil, following the addition of inoculum of T. koningii. It is proposed that both the abiotic and biotic environments of soil can influence the expression of transferable pathogen suppression which, in the soils tested, is related to the activity of Trichoderma spp.
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Fichtner, E. J., D. L. Hesterberg e H. D. Shew. "Nonphytotoxic Aluminum-Peat Complexes Suppress Phytophthora parasitica". Phytopathology® 91, n.º 11 (novembro de 2001): 1092–97. http://dx.doi.org/10.1094/phyto.2001.91.11.1092.
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Amendment of peat-based potting media with Al2(SO4)3 suppresses damping-off of Vinca (Catharanthus roseus) caused by Phytophthora parasitica. The species of aluminum (Al) responsible for disease suppression have not been identified. The objective of this study was to determine the effects of amount and pH of Al2(SO4)3 amendment solutions on survival of P. parasitica. In separate experiments, peat was amended with Al2(SO4)3 solutions adjusted to pH 4 or 6 at either 0.0158 or 0.0079 g of Al per gram of peat. Amended peat was placed in Büchner funnels maintained at -2.5 kPa matric potential. Peat was infested with P. parasitica by placing zero, two, or five colonized Vinca leaf disks in each funnel, and 15 Vinca seeds were placed in each funnel. After 24 h, the matric potential was brought to 0 kPa to induce zoospore release and returned to -2.5 kPa after 24 h. Pathogen populations and stand counts were assessed after 2-week incubation. Al amendment solutions at both pH 4 and 6 reduced pathogen populations at 0.0158 g of Al per gram of peat. Solutions at pH 4 reduced pathogen populations by more than 90% at both inoculum levels; amendment solutions at pH 6 reduced populations by 95% at the low inoculum level and 65% at the high inoculum level. The prevalence of Al(OH)2+ in peat amended with Al2(SO4)3 solution at pH 6 suggests that ions other than Al3+ may be responsible for pathogen suppression. Based on the difference in chemical conditions of Al-amended peat and suppressive mineral soils, the mechanism of Al-mediated suppression of plant pathogens is speculated to be different in the two systems. Peat containing Al-peat complexes was chemically suppressive to P. parasitica and may confer Al-mediated suppression of plant pathogens with a nonphytotoxic form of Al.
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Shen, Zongzhuan, Linda S. Thomashow, Yannan Ou, Chengyuan Tao, Jiabao Wang, Wu Xiong, Hongjun Liu, Rong Li, Qirong Shen e George A. Kowalchuk. "Shared Core Microbiome and Functionality of Key Taxa Suppressive to Banana Fusarium Wilt". Research 2022 (16 de setembro de 2022): 1–15. http://dx.doi.org/10.34133/2022/9818073.
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Microbial contributions to natural soil suppressiveness have been reported for a range of plant pathogens and cropping systems. To disentangle the mechanisms underlying suppression of banana Panama disease caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc4), we used amplicon sequencing to analyze the composition of the soil microbiome from six separate locations, each comprised of paired orchards, one potentially suppressive and one conducive to the disease. Functional potentials of the microbiomes from one site were further examined by shotgun metagenomic sequencing after soil suppressiveness was confirmed by greenhouse experiments. Potential key antagonists involved in disease suppression were also isolated, and their activities were validated by a combination of microcosm and pot experiments. We found that potentially suppressive soils shared a common core community with relatively low levels of F. oxysporum and relatively high proportions of Myxococcales, Pseudomonadales, and Xanthomonadales, with five genera, Anaeromyxobacter, Kofleria, Plesiocystis, Pseudomonas, and Rhodanobacter being significantly enriched. Further, Pseudomonas was identified as a potential key taxon linked to pathogen suppression. Metagenomic analysis showed that, compared to the conducive soil, the microbiome in the disease suppressive soil displayed a significantly greater incidence of genes related to quorum sensing, biofilm formation, and synthesis of antimicrobial compounds potentially active against Foc4. We also recovered a higher frequency of antagonistic Pseudomonas isolates from disease suppressive experimental field sites, and their protective effects against banana Fusarium wilt disease were demonstrated under greenhouse conditions. Despite differences in location and soil conditions, separately located suppressive soils shared common characteristics, including enrichment of Myxococcales, Pseudomonadales, and Xanthomonadales, and enrichment of specific Pseudomonas populations with antagonistic activity against the pathogen. Moreover, changes in functional capacity toward an increase in quorum sensing, biofilm formation, and antimicrobial compound synthesizing involve in disease suppression.
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Aslam, Saman. "Non-pathogenic Fusarium oxysporum contributes in the biological suppression of pea wilt in disease suppressive soil". Pakistan Journal of Agricultural Sciences 59, n.º 02 (1 de janeiro de 2022): 199–206. http://dx.doi.org/10.21162/pakjas/22.9093.
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Peas are growing all over the world as a leguminous crop due to high nutrients value. Fusarium wilt of peas is a destructive disease and causing deleterious loses in pea growing regions of the world. The fields were surveyed with disease incidence of Fusarium wilt in major pea growing areas. Fields with heavy pathogen infestation and natural disease suppressive were observed at District Sahiwal, Pakistan. The samples were collected to diagnose the disease and factors responsible in the suppression of disease. The results of soil physio-chemical properties showed no significant differences between diseased and suppressive soils. Pathogenicity assays both in-vitro and pot trial showed that suppressive soil has natural ability to suppress the disease. Furthermore, in-vitro and pot assays were designed with different soil treatments to investigate the factors responsible in the natural disease suppressiveness in suppressive soil. The results demonstrated that the mechanism involved in disease suppressive soil is biotic in nature. All isolated fungal strains from diseased and healthy roots of pea were subjected to biological assays to evaluate the virulence. The assays showed that isolate SAH09 is non-pathogenic Fusarium oxysporum which was isolated from the pea roots of suppressive soil. Isolate SAH09 was used in dual culturing technique and pot trial to evaluate the mycoparastism behavior against virulent pathogenic isolates SAH03, SAH05 and SAH10. Results concluded that isolate SAH09 of non-pathogenic Fusarium oxysporum has potential to suppress the growth of all isolates of pathogenic Fusarium and possibly play the role in natural disease suppression in suppressive soils
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Hong, Shan, Hongling Jv, Xianfu Yuan, Jianjian Geng, Beibei Wang, Yan Zhao, Qing Wang, Rong Li, Zhongjun Jia e Yunze Ruan. "Soil Organic Nitrogen Indirectly Enhances Pepper-Residue-Mediated Soil Disease Suppression through Manipulation of Soil Microbiome". Agronomy 12, n.º 9 (31 de agosto de 2022): 2077. http://dx.doi.org/10.3390/agronomy12092077.
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Banana Fusarium wilt-suppressive soils are effective against pathogen invasion, yet soil physicochemical factors responsible for conducive or suppressive behavior have not been reported. Here, we investigated the changes in banana biomass, disease incidence (DI), soil culturable microbes and physicochemical properties by incorporating pepper and banana residues into conducive and suppressive soils. Before the incorporation of any residues, the suppressive soil significantly increased banana biomass and decreased DI compared to the conducive soil. The biomass of the suppressive soil was significantly higher than that of the conducive soil after the incorporation of either pepper or banana residues. Compared with the control (CK), the incorporation of pepper residues to both soils significantly reduced DI, while banana residues had the opposite effect. Additionally, both conducive and suppressive soils supplemented with pepper residues significantly reduced the amounts of culturable Fusarium oxysporum and increased the amounts of beneficial Pseudomonas and Bacillus. The pepper residue extracts significantly inhibited the growth of F. oxysporum mycelium. Soil alkali-hydrolyzable nitrogen (AN) responded most strongly to residue application to suppressive soil. The AN factor was significantly and positively correlated with banana biomass; however, there was no direct and significant negative correlation with DI. Further analysis of the results showed that elevated AN content could stimulate the amounts of culturable Bacillus in the soil, and Bacillus antagonized the proliferation of pathogen and thus indirectly and effectively reduced banana DI. In conclusion, soil AN content can indirectly improve the disease suppression ability of pepper-residue-mediated suppressive soil by manipulating the soil microbiome.
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Hayden, Zachary D., Daniel C. Brainard, Ben Henshaw e Mathieu Ngouajio. "Winter Annual Weed Suppression in Rye–Vetch Cover Crop Mixtures". Weed Technology 26, n.º 4 (dezembro de 2012): 818–25. http://dx.doi.org/10.1614/wt-d-12-00084.1.
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Winter annual weeds can interfere directly with crops and serve as alternative hosts for important pests, particularly in reduced tillage systems. Field experiments were conducted on loamy sand soils at two sites in Holt, MI, between 2008 and 2011 to evaluate the relative effects of cereal rye, hairy vetch, and rye–vetch mixture cover crops on the biomass and density of winter annual weed communities. All cover crop treatments significantly reduced total weed biomass compared with a no-cover-crop control, with suppression ranging from 71 to 91% for vetch to 95 to 98% for rye. In all trials, the density of nonmustard family broadleaf weeds was either not suppressed or suppressed equally by all cover crop treatments. In contrast, the density of mustard family weed species was suppressed more by rye and rye–vetch mixtures than by vetch. Cover crops were more consistently suppressive of weed dry weight per plant than of weed density, with rye-containing cover crops generally more suppressive than vetch. Overall, rye was most effective at suppressing winter annual weeds; however, rye–vetch mixtures can match the level of control achieved by rye, in addition to providing a potential source of fixed nitrogen for subsequent cash crops.
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Pandeya, Devendra, Damar L. López-Arredondo, Madhusudhana R. Janga, LeAnne M. Campbell, Priscila Estrella-Hernández, Muthukumar V. Bagavathiannan, Luis Herrera-Estrella e Keerti S. Rathore. "Selective fertilization with phosphite allows unhindered growth of cotton plants expressing the ptxD gene while suppressing weeds". Proceedings of the National Academy of Sciences 115, n.º 29 (4 de junho de 2018): E6946—E6955. http://dx.doi.org/10.1073/pnas.1804862115.
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Weeds, which have been the bane of agriculture since the beginning of civilization, are managed manually, mechanically, and, more recently, by chemicals. However, chemical control options are rapidly shrinking due to the recent rise in the number of herbicide-resistant weeds in crop fields, with few alternatives on the horizon. Therefore, there is an urgent need for alternative weed suppression systems to sustain crop productivity while reducing our dependence on herbicides and tillage. Such a development will also allay some of the negative perceptions associated with the use of herbicide-resistance genes and heavy dependence on herbicides. Transgenic plants expressing the bacterial phosphite dehydrogenase (ptxD) gene gain an ability to convert phosphite (Phi) into orthophosphate [Pi, the metabolizable form of phosphorus (P)]. Such plants allow for a selective fertilization scheme, based on Phi as the sole source of P for the crop, while offering an effective alternative for suppressing weed growth. Here, we show that, when P is supplied in the form of Phi, ptxD-expressing cotton (Gossypium hirsutum L.) plants outcompete, in both artificial substrates and natural soils from agricultural fields, three different monocot and dicot weed species intentionally introduced in the experiments, as well as weeds naturally present in the tested soils. Importantly, the ptxD/Phi system proved highly efficacious in inhibiting the growth of glyphosate-resistant Palmer amaranth. With over 250 weed species resistant to currently available herbicides, ptxD-transgenic plants fertilized with Phi could provide an effective alternative to suppressing the growth of these weeds while providing adequate nutrition to the crop.
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Mazzola, Mark, David M. Granatstein, Don C. Elfving, Kent Mullinix e Yu-Huan Gu. "Cultural Management of Microbial Community Structure to Enhance Growth of Apple in Replant Soils". Phytopathology® 92, n.º 12 (dezembro de 2002): 1363–66. http://dx.doi.org/10.1094/phyto.2002.92.12.1363.
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Apple replant disease typically is managed through pre-plant application of broad-spectrum soil fumigants including methyl bromide. The impending loss or restricted use of soil fumigants and the needs of an expanding organic tree fruit industry necessitate the development of alternative control measures. The microbial community resident in a wheat field soil was shown to suppress components of the microbial complex that incites apple replant disease. Pseudomonas putida was the primary fluorescent pseudomonad recovered from suppressive soil, whereas Pseudomonas fluorescens bv. III was dominant in a conducive soil; the latter developed within 3 years of orchard establishment at the same site. In greenhouse studies, cultivation of wheat in replant orchard soils prior to planting apple suppressed disease development. Disease suppression was induced in a wheat cultivar-specific manner. Wheat cultivars that enhanced apple seedling growth altered the dominant fluorescent pseudo-monad from Pseudomonas fluorescens bv. III to Pseudomonas putida. The microbial community resident in replant orchard soils after growing wheat also was suppressive to an introduced isolate of Rhizoctonia solani anastomosis group 5, which causes root rot of apple. Incorporation of high glucosinolate containing rapeseed (‘Dwarf Essex’) meal also enhanced growth of apple in replant soils through suppression of Rhizoc-tonia spp., Cylindrocarpon spp., and Pratylenchus penetrans. Integration of these methods will require knowledge of the impact of the biofumigant component on the wheat-induced disease-suppressive microbial community. Implementation of these control strategies for management of apple replant disease awaits confirmation from ongoing field validation trials.
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Shimizu, Yukari, Daiki Sagiya, Mariko Matsui e Ryo Fukui. "Zonal Soil Amendment with Simple Sugars to Elevate Soil C/N Ratios as an Alternative Disease Management Strategy for Rhizoctonia Damping-off of Sugar Beet". Plant Disease 102, n.º 7 (julho de 2018): 1434–44. http://dx.doi.org/10.1094/pdis-09-16-1279-re.
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Effects of monosaccharide-amended soils on suppression of Rhizoctonia damping-off of sugar beet were compared under controlled experiments. Suppressive effects of glucose, fructose, sorbose, and xylose were significantly (P < 0.001) greater than that of galactose or mannose but the effect of sorbose was reduced by soil treatments with antibiotics. Saprotrophic growth of Rhizoctonia solani in the laimosphere also was suppressed by glucose, fructose, sorbose, and xylose, whereas only sorbose repressed pericarp colonization. Sugar alcohols (mannitol, sorbitol, and xylitol) neither suppressed Rhizoctonia damping-off nor halted the saprotrophic growth of the pathogen. Seed germination was not affected by any of these six monosaccharides, whereas galactose and mannose inhibited seedling emergence significantly (P < 0.001) compared with the nontreated control or other monosaccharides. Soil fertilization with inorganic nitrogen at a C/N ratio of 20:1 negated the suppressive effects of glucose and fructose on both damping-off and saprotrophic colonization but improved seedling growth in carbonized soils. Obviously, microbial competition for mineral nitrogen was responsible for disease suppression; however, it delayed seedling growth after emergence. This paradox was resolved by adding glucose to the top 1-cm surface-soil zone at a C/N ratio of 50:1 or 125:1. This protected the laimosphere, resulting in effective disease suppression while complementarily enhancing seedling growth.
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Kasuya, Masahiro, Andriantsoa R. Olivier, Yoko Ota, Motoaki Tojo, Hitoshi Honjo e Ryo Fukui. "Induction of Soil Suppressiveness Against Rhizoctonia solani by Incorporation of Dried Plant Residues into Soil". Phytopathology® 96, n.º 12 (dezembro de 2006): 1372–79. http://dx.doi.org/10.1094/phyto-96-1372.
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Suppressive effects of soil amendment with residues of 12 cultivars of Brassica rapa on damping-off of sugar beet were evaluated in soils infested with Rhizoctonia solani. Residues of clover and peanut were tested as noncruciferous controls. The incidence of damping-off was significantly and consistently suppressed in the soils amended with residues of clover, peanut, and B. rapa subsp. rapifera ‘Saori’, but only the volatile substance produced from water-imbibed residue of cv. Saori exhibited a distinct inhibitory effect on mycelial growth of R. solani. Nonetheless, disease suppression in such residue-amended soils was diminished or nullified when antibacterial antibiotics were applied to the soils, suggesting that proliferation of antagonistic bacteria resident to the soils were responsible for disease suppression. When the seed (pericarps) colonized by R. solani in the infested soil without residues were replanted into the soils amended with such residues, damping-off was suppressed in all cases. In contrast, when seed that had been colonized by microorganisms in the soils containing the residues were replanted into the infested soil, damping-off was not suppressed. The evidence indicates that the laimosphere, but not the spermosphere, is the site for the antagonistic microbial interaction, which is the chief principle of soil suppressiveness against Rhizoctonia damping-off.
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Latif, Sajid, Saliya Gurusinghe, Paul A. Weston, William B. Brown, Jane C. Quinn, John W. Piltz e Leslie A. Weston. "Performance and weed-suppressive potential of selected pasture legumes against annual weeds in south-eastern Australia". Crop and Pasture Science 70, n.º 2 (2019): 147. http://dx.doi.org/10.1071/cp18458.
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Mixed farming systems have traditionally incorporated subterranean clover (Trifolium subterraneum L.) and lucerne (Medicago sativa L.) as key components of the pasture phase across south-eastern Australia. However, poor adaptation of subterranean clover to acidic soils, insufficient and inconsistent rainfall, high input costs, soil acidification and the emergence of herbicide-resistant weeds have reduced efficacy of some traditional clover species in recent years. To overcome these challenges, numerous novel pasture species have been selectively improved and released for establishment in Australia. Despite their suitability to Australian climate and soils, limited knowledge exists regarding their weed-suppressive ability in relation to establishment and regeneration. Field trials were therefore conducted over 3 years in New South Wales to evaluate the suppressive potential of selected pasture legume species and cultivars as monocultures and in mixed stands against dominant annual pasture weeds. Pasture and weed biomass varied significantly between pasture species when sown as monocultures, but mixtures of several species did not differ with regard to establishment and subsequent weed infestation. Arrowleaf clover (T. vesiculosum Savi.) and biserrula (Biserrula pelecinus L.) cv. Casbah showed improved stand establishment, with higher biomass and reduced weed infestation compared with other pasture species. Generally, weed suppression was positively correlated with pasture biomass; however, yellow serradella (Ornithopus compressus L.) cv. Santorini exhibited greater weed suppression than other pasture legumes while producing lower biomass, thereby suggesting a mechanism other than competition for resources affecting weed-suppressive ability. Over the period 2015–17, arrowleaf clover and biserrula cv. Casbah were generally the most consistent annual pasture legumes with respect to yearly regeneration and suppression of annual pasture weed species.
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Okalebo, Jane, Gary Y. Yuen, Rhae A. Drijber, Erin E. Blankenship, Cafer Eken e John L. Lindquist. "Biological Suppression of Velvetleaf (Abutilon theophrasti) in an Eastern Nebraska Soil". Weed Science 59, n.º 2 (junho de 2011): 155–61. http://dx.doi.org/10.1614/ws-d-10-00115.1.
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Weed-suppressive soils contain naturally occurring microorganisms that suppress a weed by inhibiting its growth, development, and reproductive potential. Increased knowledge of microbe–weed interactions in such soils could lead to the identification of management practices that create or enhance soil suppressiveness to weeds. Velvetleaf death and growth suppression was observed in a research field (fieldA) that was planted with high populations of velvetleaf, which may have developed via microbial mediated plant–soil feedback. Greenhouse studies were conducted with soil collected fromfieldA(soilA) to determine if it was biologically suppressive to velvetleaf. In one study, mortality of velvetleaf grown for 8 wk insoilAwas greatest (86%) and biomass was smallest (0.3 g plant−1) in comparison to soils collected from surrounding fields with similar structure and nutrient content, indicating that suppressiveness ofsoilAwas not likely caused by physical or chemical factors. WhensoilAwas autoclaved in another study, mortality of velvetleaf plants in the heat-treated soil was reduced to 4% compared to 55% for the untreated soil, thus suggesting that suppressiveness ofsoilAis biological in nature. A third set of experiments showed that suppressiveness to velvetleaf could be transferred to an autoclaved soil by amending the autoclaved soil with untreatedsoilA; this provided additional evidence for a biological basis for the effects ofsoilA.The suppressive condition in these greenhouse experiments was associated with high soil populations of fusaria.Fusarium lateritiumwas the most frequently isolated fungus from roots of diseased velvetleaf plants collected fromfieldA, and also was the most virulent when inoculated onto velvetleaf seedlings. Results of this research indicate that velvetleaf suppression can occur naturally in the field and thatF. lateritiumis an important cause of velvetleaf mortality infieldA.
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Inderbitzin, Patrik, Judson Ward, Alexandra Barbella, Natalie Solares, Dmitriy Izyumin, Prabir Burman, Dan O. Chellemi e Krishna V. Subbarao. "Soil Microbiomes Associated with Verticillium Wilt-Suppressive Broccoli and Chitin Amendments are Enriched with Potential Biocontrol Agents". Phytopathology® 108, n.º 1 (janeiro de 2018): 31–43. http://dx.doi.org/10.1094/phyto-07-17-0242-r.
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Two naturally infested Verticillium wilt-conducive soils from the Salinas Valley of coastal California were amended with disease-suppressive broccoli residue or crab meal amendments, and changes to the soil prokaryote community were monitored using Illumina sequencing of a 16S ribosomal RNA gene library generated from 160 bulk soil samples. The experiment was run in a greenhouse, twice, with eggplant as the Verticillium wilt-susceptible host. Disease suppression, plant height, soil microsclerotia density, and soil chitinase activity were assessed at the conclusion of each experiment. In soil with high microsclerotia density, all amendments significantly reduced Verticillium wilt severity and microsclerotia density, and increased soil chitinase activity. Plant height was increased only in the broccoli-containing treatments. In total, 8,790 error-corrected sequence variants representing 1,917,893 different sequences were included in the analyses. The treatments had a significant impact on the soil microbiome community structure but measures of α diversity did not vary between treatments. Community structure correlated with disease score, plant height, microsclerotia density, and soil chitinase activity, suggesting that the prokaryote community may affect the disease-related response variables or vice versa. Similarly, the abundance of 107 sequence variants correlated with disease-related response variables, which included variants from genera with known antagonists of filamentous fungal plant pathogens, such as Pseudomonas and Streptomyces. Overall, genera with antifungal antagonists were more abundant in amended soils than unamended soils, and constituted up to 8.9% of all sequences in broccoli+crabmeal-amended soil. This study demonstrates that substrate-mediated shifts in soil prokaryote communities are associated with the transition of Verticillium wilt-conducive soils to Verticillium wilt-suppressive soils, and suggests that soils likely harbor numerous additional antagonists of fungal plant pathogens that contribute to the biological suppression of plant disease.
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Slyusarev, V., A. Osipov, V. Vlasenko e I. Suminsky. "Mycological composition of soils in Kuban rice agrocenoses as a biotic component for their health". E3S Web of Conferences 389 (2023): 04005. http://dx.doi.org/10.1051/e3sconf/202338904005.
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Studies of the water-physical, physical-chemical and biological properties of meadow-chernozem soils were carried out on a rice irrigation system located in the present-day delta of the Kuban River. Rice meadow-chernozem soils have good water and general physical properties of humus layers. An increase in compaction is observed in the lower horizons of these soils. Meadow-chernozem soils are distinguished by low content of organic matter in arable horizons (3,2-3,4 %), neutral reaction of soil solution (рН 6,8-6,9) and high indices of cation exchange capacity (38,7-39,1 mmol/100g). The mycological composition of the studied soils in the autumn-spring periods was identified and identified. The soil was more saturated with representatives of the suppressive group at the beginning of rice vegetation, the opportunistic group was not detected and the antiphytopathogenic potential was 1:2. The spring-fed rice crop rotations soils are prone to soil stresses that are oversaturated with suppressors. In autumn, the ratio of conditionally suppressive to saprotrophic and pathogenic mycota was 1.5:4.5:7. The growth of colonies of the micromycete genus Trichoderma is traced, which confirms the beginning of a long process and the slow recovery of soil degradation processes.
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Nakajima, Tsuyoshi, Shinya Suzuki, Genki Futatsubashi, Hiroyuki Ohtsuska, Rinaldo A. Mezzarane, Trevor S. Barss, Taryn Klarner, E. Paul Zehr e Tomoyoshi Komiyama. "Regionally distinct cutaneous afferent populations contribute to reflex modulation evoked by stimulation of the tibial nerve during walking". Journal of Neurophysiology 116, n.º 1 (1 de julho de 2016): 183–90. http://dx.doi.org/10.1152/jn.01011.2015.
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During walking, cutaneous reflexes in ankle flexor muscle [tibialis anterior (TA)] evoked by tibial nerve (TIB) stimulation are predominantly facilitatory at early swing phase but reverse to suppression at late swing phase. Although the TIB innervates a large portion of the skin of the foot sole, the extent to which specific foot-sole regions contribute to the reflex reversals during walking remains unclear. Therefore, we investigated regional cutaneous contributions from discrete portions of the foot sole on reflex reversal in TA following TIB stimulation during walking. Summation effects on reflex amplitudes, when applying combined stimulation from foot-sole regions with TIB, were examined. Middle latency responses (MLRs; 70–120 ms) after TIB stimulation were strongly facilitated during the late stance to mid-swing phases and reversed to suppression just before heel (HL) strike. Both forefoot-medial (f-M) and forefoot-lateral stimulation in the foot sole induced facilitation during stance-to-swing transition phases, but HL stimulation evoked suppression during the late stance to the end of swing phases. At the stance-to-swing transition, a summation of MLR amplitude occurred only for combined f-M&TIB stimulation. However, the same was not true for the combined HL&TIB stimulation. At the swing-to-stance transition, there was a suppressive reflex summation only for HL&TIB stimulation. In contrast, this summation was not observed for the f-M&TIB stimulation. Our results suggest that reflex reversals evoked by TIB stimulation arise from distinct reflex pathways to TA produced by separate afferent populations innervating specific regions of the foot sole.
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Barnett, Stephen J., David K. Roget e Maarten H. Ryder. "Suppression of Rhizoctonia solani AG-8 induced disease on wheat by the interaction between Pantoea, Exiguobacterium, and Microbacteria". Soil Research 44, n.º 4 (2006): 331. http://dx.doi.org/10.1071/sr05113.
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Rhizoctonia solani AG-8 is a major wheat root pathogen; however, soils can become suppressive to the expression of disease under intensive cropping with retention of crop residues. This is in part due to the action of soil microorganisms. A step-wise approach was used to determine which microorganisms contributed to suppression of R. solani induced disease in a disease-suppressive soil. Using wheat-soil-pathogen bioassays it was determined that the interaction between 3 phylogenetically diverse groups of bacteria, Pantoea agglomerans, Exiguobacterium acetylicum, and Microbacteria (family Microbacteriaceae), was a major contributor to disease suppression. Inoculation of a sterilised soil with the combination of these groups resulted in greatly increased seedling shoot dry weight and reduced infection compared with diseased control plants with no bacterial inoculation, or inoculated with individual types of bacteria. These groups, however, did not reduce levels of pathogen DNA, although inoculation with suppressive soil (at 10% w/w) did reduce pathogen DNA. Root associated P. agglomerans and E. acetylicum promoted the growth of infected wheat plants and soil associated Microbacteria reduced root infection by R. solani.
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Smith, Richard G., Nicholas D. Warren e Stéphane Cordeau. "Are cover crop mixtures better at suppressing weeds than cover crop monocultures?" Weed Science 68, n.º 2 (28 de janeiro de 2020): 186–94. http://dx.doi.org/10.1017/wsc.2020.12.
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AbstractCover crops are increasingly being used for weed management, and planting them as diverse mixtures has become an increasingly popular strategy for their implementation. While ecological theory suggests that cover crop mixtures should be more weed suppressive than cover crop monocultures, few experiments have explicitly tested this for more than a single temporal niche. We assessed the effects of cover crop mixtures (5- or 6-species and 14-species mixtures) and monocultures on weed abundance (weed biomass) and weed suppression at the time of cover crop termination. Separate experiments were conducted in Madbury, NH, from 2014 to 2017 for each of three temporal cover-cropping niches: summer (spring planting–summer termination), fall (summer planting–fall termination), and spring (fall planting–subsequent spring termination). Regardless of temporal niche, mixtures were never more weed suppressive than the most weed-suppressive cover crop grown as a monoculture, and the more diverse mixture (14 species) never outperformed the less diverse mixture. Mean weed-suppression levels of the best-performing monocultures in each temporal niche ranged from 97% to 98% for buckwheat (Fagopyrum esculentum Moench) in the summer niche and forage radish (Raphanus sativus L. var. niger J. Kern.) in the fall niche, and 83% to 100% for triticale (×Triticosecale Wittm. ex A. Camus [Secale × Triticum]) in the winter–spring niche. In comparison, weed-suppression levels for the mixtures ranged from 66% to 97%, 70% to 90%, and 67% to 99% in the summer, fall, and spring niches, respectively. Stability of weed suppression, measured as the coefficient of variation, was two to six times greater in the best-performing monoculture compared with the most stable mixture, depending on the temporal niche. Results of this study suggest that when weed suppression is the sole objective, farmers are more likely to achieve better results planting the most weed-suppressive cover crop as a monoculture than a mixture.
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Lee, Jaeyun, Woo-Jin Song, Hyang Woon Lee e Hyun-Chool Shin. "Novel Burst Suppression Segmentation in the Joint Time-Frequency Domain for EEG in Treatment of Status Epilepticus". Computational and Mathematical Methods in Medicine 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/2684731.
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We developed a method to distinguish bursts and suppressions for EEG burst suppression from the treatments of status epilepticus, employing the joint time-frequency domain. We obtained the feature used in the proposed method from the joint use of the time and frequency domains, and we estimated the decision as to whether the measured EEG was a burst segment or suppression segment by the maximum likelihood estimation. We evaluated the performance of the proposed method in terms of its accordance with the visual scores and estimation of the burst suppression ratio. The accuracy was higher than the sole use of the time or frequency domains, as well as conventional methods conducted in the time domain. In addition, probabilistic modeling provided a more simplified optimization than conventional methods. Burst suppression quantification necessitated precise burst suppression segmentation with an easy optimization; therefore, the excellent discrimination and the easy optimization of burst suppression by the proposed method appear to be beneficial.
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Zhang, Na, Chengzhi Zhu, Zongzhuan Shen, Chengyuan Tao, Yannan Ou, Rong Li, Xuhui Deng, Qirong Shen e Francisco Dini-Andreote. "Partitioning the Effects of Soil Legacy and Pathogen Exposure Determining Soil Suppressiveness via Induced Systemic Resistance". Plants 11, n.º 21 (23 de outubro de 2022): 2816. http://dx.doi.org/10.3390/plants11212816.
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Beneficial host-associated bacteria can assist plant protection against pathogens. In particular, specific microbes are able to induce plant systemic resistance. However, it remains largely elusive which specific microbial taxa and functions trigger plant immune responses associated with disease suppression. Here, we experimentally studied this by setting up two independent microcosm experiments that differed in the time at which plants were exposed to the pathogen and the soil legacy (i.e., soils with historically suppressive or conducive). Overall, we found soil legacy effects to have a major influence on disease suppression irrespective of the time prior to pathogen exposure. Rhizosphere bacterial communities of tomato plants were significantly different between the two soils, with potential beneficial strains occurring at higher relative abundances in the suppressive soil. Root transcriptome analysis revealed the soil legacy to induce differences in gene expression, most importantly, genes involved in the pathway of phenylpropanoid biosynthesis. Last, we found genes in the phenylpropanoid biosynthesis pathway to correlate with specific microbial taxa, including Gp6, Actinomarinicola, Niastella, Phaeodactylibacter, Longimicrobium, Bythopirellula, Brevundimonas, Ferruginivarius, Kushneria, Methylomarinovum, Pseudolabrys, Sphingobium, Sphingomonas, and Alterococcus. Taken together, our study points to the potential regulation of plant systemic resistance by specific microbial taxa, and the importance of soil legacy on disease incidence and eliciting plant-defense mechanisms.
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Lin, Chuan, e Haomiao Zhai. "Analysis on Relationship between Accurate Poverty Alleviation and Stock Price Collapse Risk from the Perspective of Information Disclosure". Discrete Dynamics in Nature and Society 2021 (21 de dezembro de 2021): 1–14. http://dx.doi.org/10.1155/2021/1033499.
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Accurate poverty alleviation (APA) is crucial to building a well-off society in an all-round way. Companies and the capital market are implementers of APA. In the context of stock price collapse risk (SPCR), this paper verifies whether the APA by state-owned listed enterprises (SOLEs) could effectively suppress SPCR. Empirical results show that SOLEs engaging in APA and investing heavily in APA have a relatively low SPCR. This conclusion holds after the control of robustness and endogenous factors. Information disclosure system mediates the effect of APA on SPCR. Besides, APA suppresses SPCR more significantly in central state-owned enterprises (SOEs) and public welfare SOEs. Further analysis indicates that good institutional environment, strong poverty alleviation pressure, poverty experience of executives, and model of party organization governance can effectively enhance the influence of APA on SPCR. The research results suggest that SOLEs actively engaging in APA can effectively suppress SPCR by disclosing APA information. This is an organic manifestation of APA effectiveness in the capital market.
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Rosenzweig, Noah, James M. Tiedje, John F. Quensen, Qingxiao Meng e Jianjun J. Hao. "Microbial Communities Associated with Potato Common Scab-Suppressive Soil Determined by Pyrosequencing Analyses". Plant Disease 96, n.º 5 (maio de 2012): 718–25. http://dx.doi.org/10.1094/pdis-07-11-0571.
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Potato common scab, caused by Streptomyces spp., is an annual production problem for potato growers, and not effectively controlled by current methods. A field with naturally occurring common scab suppression has been identified in Michigan, and confirmed to have a biological basis for this disease suppression. This field and an adjacent scab nursery conducive to disease were studied using pyrosequencing to compare the two microbial communities. Total DNA was extracted from both the disease-conducive and -suppressive soils. A phylogenetically taxon-informative region of the 16S rRNA gene was used to establish operational taxonomic units (OTUs) to characterize bacterial community richness and diversity. In total, 1,124 OTUs were detected and 565 OTUs (10% dissimilarity) were identified in disease-conducive soil and 859 in disease-suppressive soil, including 300 shared both between sites. Common phyla based on relative sequence abundance were Acidobacteria, Proteobacteria, and Firmicutes. Sequences of Lysobacter were found in significantly higher numbers in the disease-suppressive soil, as were sequences of group 4 and group 6 Acidobacteria. The relative abundance of sequences identified as the genus Bacillus was significantly higher by an order of magnitude in the disease-conducive soil.
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Yang, Yanyan, Junnan Wu, Roland N. Perry e Koki Toyota. "Evaluation of Soil Suppressiveness of Various Japanese Soils against the Soybean Cyst Nematode Heterodera glycines and Its Relation with the Soil Chemical and Biological Properties". Agronomy 13, n.º 11 (16 de novembro de 2023): 2826. http://dx.doi.org/10.3390/agronomy13112826.
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This study aimed to evaluate the suppressive potential of different soils on soybean cyst nematodes (SCN) and to estimate the suppressive mechanism. Fifteen soils (designated as soil A to O) from different agricultural fields with varying organic inputs were added with SCN-infested soil and grown with a green soybean variety. The SCN density in the soil at 6 weeks of soybean growth was markedly different depending on the soils used, indicating a different level of disease suppressiveness. No significant correlation was observed between the SCN density and any of the soil physicochemical and biological characteristics tested. Then, to estimate a suppression mechanism, F-soil that showed the lowest density of SCN was added to the SCN-infested soil with or without streptomycin to kill bacteria and grown with soybean. SCN density was not increased by the addition of streptomycin, indicating that soil bacteria may not be involved in the suppressiveness of F-soil. In total, 128 fungal strains were isolated from the rhizosphere of F-soil and inoculated in a combination or singly in the SCN-infested soil. After repeated screenings, five strains were selected since the SCN density was consistently decreased by them. Sequence analysis showed that they were closest to Clonostachys rosea, Aspergillus niger, Aspergillus fumigatus, Fusarium oxysporum, and Cylindrodendrum alicantinum. All five strains significantly reduced the mobility of second-stage juveniles (J2). Further, C. rosea a2, A. niger a8, and F. oxysporum a25 significantly decreased hatching. Overall, the present study demonstrated that soil fungi played an important role in SCN suppression in F-soil.
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Alabouvette, Claude. "Fusarium wilt suppressive soils: an example of disease-suppressive soils". Australasian Plant Pathology 28, n.º 1 (1999): 57. http://dx.doi.org/10.1071/ap99008.
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Min, Yu Yu, e Koki Toyota. "Suppression of Meloidogyne incognita in different agricultural soils and possible contribution of soil fauna". Nematology 15, n.º 4 (2013): 459–68. http://dx.doi.org/10.1163/15685411-00002693.
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A total of 12 soils collected from different agricultural fields, having different backgrounds of organic input, were evaluated for their suppressive potential against Meloidogyne incognita. Second-stage juveniles (J2) of M. incognita were inoculated into the soils and their survival was evaluated. The number of M. incognita J2 5 days after inoculation differed depending on soil and was significantly lower in two soils, suggesting higher suppressiveness against M. incognita in these soils. This was confirmed by an experiment using tomato as a test plant, in which the gall formation was significantly lower in the two soils than in other soils. To estimate the contribution of below-ground biota to the suppressiveness, numbers of nematodes (predator, omnivore, bacterivore and fungivore) and other soil fauna such as tardigrades and rotifers, were counted. Some soil chemical and biological properties were also measured. Results from multiple linear regression analysis suggested that the number of rotifers, microbial activity, soil pH and total C may be involved in the suppression. The relationship between the suppressiveness and soil chemical and biological parameters is discussed.
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Mazzola, Mark, Jack Brown, Xiaowen Zhao, Antonio D. Izzo e Gennaro Fazio. "Interaction of Brassicaceous Seed Meal and Apple Rootstock on Recovery of Pythium spp. and Pratylenchus penetrans from Roots Grown in Replant Soils". Plant Disease 93, n.º 1 (janeiro de 2009): 51–57. http://dx.doi.org/10.1094/pdis-93-1-0051.
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Pythium spp. and Pratylenchus penetrans are significant components of the diverse pathogen complex that incites apple replant disease in Washington State. The structure of the Pythium population differs among orchard soils but is composed of multiple pathogenic species. Studies were conducted to determine the effect of brassicaceous seed meals and apple rootstock on the activity and composition of these pathogen populations. Brassicaceous seed meals differed in capacity to suppress Pythium numbers and apple root infection, as well as differentially transformed composition of the population recovered from apple roots. Brassica juncea seed meal (SM) was the sole seed meal examined to suppress Pythium numbers and root infection; however, a persisting population was always detected in which Pythium irregulare existed as the dominant or co-dominant species. In general, the Geneva series rootstocks were less susceptible to root infection by native populations of Pythium, whereas M26, MM106, and MM111 were highly susceptible. Apple rootstocks from the Geneva series consistently supported lower populations of P. penetrans than did Malling or Malling-Merton rootstocks. B. juncea SM was superior to Brassica napus SM or Sinapis alba SM in suppressing lesion nematode populations. Significant rootstock × seed meal interaction was detected, and nematode suppression in response to B. napus or S. alba SM was only observed when used in concert with a tolerant rootstock, while B. juncea SM suppressed lesion nematode root populations irrespective of rootstock. These findings demonstrate that utilization of brassicaceous seed meal amendments for replant disease suppression must employ an appropriate rootstock in order to achieve optimal disease control.
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Guo, Changqing, Hongmei Wang, Dianbo Zou, Yue Wang e Xiaori Han. "A novel amended nitrification inhibitor confers an enhanced suppression role in the nitrification of ammonium in soil". Journal of Soils and Sediments 22, n.º 3 (2 de janeiro de 2022): 831–43. http://dx.doi.org/10.1007/s11368-021-03118-3.
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Abstract Purpose Nitrification inhibitor plays an important regulatory role in inhibiting the nitrification of ammonium in soils. However, most of nitrification inhibitors lack the sustainable effects in suppressing the nitrification of ammonium. In this study, a novel DMS nitrification inhibitor was prepared and tested to explore its lasting effect of nitrification suppression in black soil. Materials and methods Both culture experiments and field trial were performed in black soils. Three kinds of nitrification inhibitors (NIs), dicyandiamide (DCD) with low bioactivity, 3,4-dimethylpyrazole phosphate (DMPP) with high bioactivity, and a novel 3,4-dimethylpyrazole sulfate zinc (DMS) with long half-life, were applied into soils, respectively, and the abundance changes of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were investigated; then, the accumulation changes of inorganic nitrogen, nitrogen use efficiency, and crop yields were furtherly evaluated. Results and discussions A novel DMS nitrification inhibitor with high activity and long half-life maintained a persistent effect of nitrification suppression, and remarkably increased the accumulation of ammonium nitrogen in soil, thus improving nitrogen use efficiency and crop yields. This study implies that lowering the nitrogen loss of nitrification-triggered in soil is of great importance for improving nitrogen use efficiency. Conclusions This study provided an insight into the sustainable nitrification suppression of a novel DMS nitrification inhibitor under excessive application of nitrogen fertilizer in black soils. Compared with improving the activity, reasonably prolonging the validity of nitrification inhibitors in soil is a more important strategy increasing the sustainable effects of nitrification inhibition, and the survival period of nitrification inhibitors in soil should be a crucial factor improving nitrogen use efficiency.
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Shrivastava, Mansi, Sarfaraz Alam e L. K. Dwivedi. "Hijack and exploitation of host SOCS proteins: An immunosuppressive deception of the viruses". South Asian Journal of Experimental Biology 3, n.º 6 (4 de janeiro de 2014): 314–18. http://dx.doi.org/10.38150/sajeb.3(6).p314-318.
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The suppressors of cytokine signaling (SOCS) are a cytoplasmic protein family that completes a negative feedback loop to attenuate signal transduction from cytokines through the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. They work as a natural precaution to pre-vent excessive immune responses that could cause collateral damage to body tissues. But viruses use SOCS proteins to suppress the proportionate immune response also so that a vulnerable environment can be developed in host body to let them grow freely. In several cases, an increased expression of SOCS proteins has been reported in virus infected individuals, which is believed to be induced by the viruses to inhibit the anti-proliferative and antiviral activity of cytokines (Interferon) of host body. Viruses including HIV hijack the expression of SOCS proteins and manipulate them in a way where they support the onset of antigens in host body by suppressing the cell sig-nalling of immune response. Detailed mechanism of the same and an alter-native way to stop viral infection by restoring the normal SOCS expression is discussed in the present review.
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Elliott, Joanne, Michelle B. Hookham e James A. Johnston. "The suppressors of cytokine signalling E3 ligases behave as tumour suppressors". Biochemical Society Transactions 36, n.º 3 (21 de maio de 2008): 464–68. http://dx.doi.org/10.1042/bst0360464.
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Many studies have suggested that E3 ubiquitin ligases can behave as either oncogenes or tumour suppressor genes and, recently, it has become clear that the SOCS (suppressor of cytokine signalling) E3 ligases fit this mould. While most cancer-associated E3s regulate the cell cycle or DNA repair, the SOCS proteins inhibit growth factor responses by degrading signalling intermediates such as JAKs (Janus kinases) via the SOCS-box-associated ECS (Elongin–Cullin–SOCS) E3 ligase. Clinical studies have found that (epi)genetic (mutation or methylation) phenomena can occur in many solid tumours and a growing number of clinical findings reveal post-translational modifications that disrupt SOCS function in haematological malignancy. In the present review, we provide a summary of the functions of the SOCS E3s and propose the potential use of members of this family as diagnostic markers and therapeutic targets in cancer.
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O’Connor, Patrick, Maria Manjarrez e Sally E. Smith. "The fate and efficacy of benomyl applied to field soils to suppress activity of arbuscular mycorrhizal fungi". Canadian Journal of Microbiology 55, n.º 7 (julho de 2009): 901–4. http://dx.doi.org/10.1139/w09-035.
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A systematic application of the fungicide benomyl was used to follow up the suppression of arbuscular mycorrhizal (AM) colonization and to determine its fungitoxic activity and persistence at different depths. Repeated applications of benomyl reduced AM colonization mainly in the upper 0–4 cm layer of the treated soils. Furthermore, AM colonization decreased with soil depth. The activity and persistence of this fungicide was reduced over small changes in depth in the first 10 cm of the soil profile beneath a semiarid herbland at Brookfield Conservation Park (South Australia). Repeated applications of the fungicide only slightly increased the levels of toxicity in the soils, probably because of biodegradation of the fungicide in soils with a recent history of exposure to the fungicide. The decline in fungicide activity at depth was correlated with a decline in the suppressive effect of the fungicide on the activity of AM fungi.
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Goh, Yit Kheng, Muhammad Zarul Hanifah Md Zoqratt, You Keng Goh, Qasim Ayub e Adeline Su Yien Ting. "Determining Soil Microbial Communities and Their Influence on Ganoderma Disease Incidences in Oil Palm (Elaeis guineensis) via High-Throughput Sequencing". Biology 9, n.º 12 (27 de novembro de 2020): 424. http://dx.doi.org/10.3390/biology9120424.
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Basal stem rot (BSR), caused by Ganoderma boninense, is the most devastating oil palm disease in South East Asia, costing US$500 million annually. Various soil physicochemical parameters have been associated with an increase in BSR incidences. However, very little attention has been directed to understanding the relationship between soil microbiome and BSR incidence in oil palm fields. The prokaryotic and eukaryotic microbial diversities of two coastal soils, Blenheim soil (Typic Quartzipsamment—calcareous shell deposits, light texture) with low disease incidence (1.9%) and Bernam soil (Typic Endoaquept—non-acid sulfate) with high disease incidence (33.1%), were determined using the 16S (V3–V4 region) and 18S (V9 region) rRNA amplicon sequencing. Soil physicochemical properties (pH, electrical conductivity, soil organic matter, nitrogen, phosphorus, cation exchange capacity, exchangeable cations, micronutrients, and soil physical parameters) were also analyzed for the two coastal soils. Results revealed that Blenheim soil comprises higher prokaryotic and eukaryotic diversities, accompanied by higher pH and calcium content. Blenheim soil was observed to have a higher relative abundance of bacterial taxa associated with disease suppression such as Calditrichaeota, Zixibacteria, GAL15, Omnitrophicaeota, Rokubacteria, AKYG587 (Planctomycetes), JdFR-76 (Calditrichaeota), and Rubrobacter (Actinobacteria). In contrast, Bernam soil had a higher proportion of other bacterial taxa, Chloroflexi and Acidothermus (Actinobacteria). Cercomonas (Cercozoa) and Calcarisporiella (Ascomycota) were eukaryotes that are abundant in Blenheim soil, while Uronema (Ciliophora) and mammals were present in higher abundance in Bernam soil. Some of the bacterial taxa have been reported previously in disease-suppressive and -conducive soils as potential disease-suppressive or disease-inducible bacteria. Furthermore, Cercomonas was reported previously as potential bacterivorous flagellates involved in the selection of highly toxic biocontrol bacteria, which might contribute to disease suppression indirectly. The results from this study may provide valuable information related to soil microbial community structures and their association with soil characteristics and soil susceptibility to Ganoderma.
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Toyota, Koki, Koko Yamamoto e Makoto Kimura. "Mechanisms of suppression ofFusarium oxysporumf. sp.raphaniin soils so-called suppressive to fusarium-wilt of radish". Soil Science and Plant Nutrition 40, n.º 3 (setembro de 1994): 373–80. http://dx.doi.org/10.1080/00380768.1994.10413315.
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N, RAJAGOPAL, VELAYUDHAM K, RAJENDRAN P e RADHAMANI S. "EFFICIENCY OF DUAL CROPPING OF GREEN MANURES WITH MAIZE ON WEED MANAGEMENT". Madras Agricultural Journal 85, september (1998): 393–95. http://dx.doi.org/10.29321/maj.10.a00765.
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Two field experiments were conducted at Tamil Nadu Agricultural University, Coimbatore during rabi. 1994 and Kharif, 1995 to investigate the weed suppressing effect of green manures grown with maize as dual crop. The results revealed that raising cowpea as a dual crop with maize at a spacing of 60 x 20 cm not only suppresses the weed growth but also supplies nutrient to the crop, resulting in highest grain yield, (62 q/ha) net return (Rs. 12,006/ha) and BC ratio (2.06) compared to 43.6 q/ha, Rs. 6376/- and 1.55 respectively under sole cropping of maize.
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Gatch, Emily W., e Lindsey J. du Toit. "Limestone-Mediated Suppression of Fusarium Wilt in Spinach Seed Crops". Plant Disease 101, n.º 1 (janeiro de 2017): 81–94. http://dx.doi.org/10.1094/pdis-04-16-0423-re.
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Fusarium wilt of spinach is caused by the soilborne fungus Fusarium oxysporum f. sp. spinaciae and occurs in most regions of spinach production. The disease is favored by acid soils and warm temperatures, and the fungus can survive extended periods as chlamydospores or by asymptomatic colonization of the roots of nonhost plant species. The 10- to 15-year rotation required to minimize losses to Fusarium wilt is the primary constraint on spinach seed production in the maritime Pacific Northwest, the only region of the United States suitable for this cool-season, daylength-sensitive crop. Raising soil pH with agricultural limestone (97% CaCO3) results in a transitory, partially suppressive effect on spinach Fusarium wilt. A field trial was completed from 2009 to 2012 to assess the potential for annual applications of agricultural limestone at 0, 2.24, and 4.48 tons/ha for 3 years prior to a spinach seed crop to improve Fusarium wilt suppression compared with the level of suppression attained from a single limestone amendment at 4.48 tons/ha. Three proprietary female spinach lines were planted that ranged from highly susceptible to partially resistant to Fusarium wilt. Three successive annual applications of limestone at 4.48 tons/ha reduced midseason wilt incidence by an average of 20%, increased spinach biomass by 33%, and increased marketable spinach seed yield by 45% compared with plots amended once with the same rate of limestone in the spring of planting. The suppressive effect increased with increasing rate of limestone amendment, with the greatest difference observed when limestone was applied at between 0 and 2.24 tons/ha annually for 3 years. The effects on seed yield were greatest for the partially resistant female line, followed by the moderately susceptible and highly susceptible female lines. Overall, the results demonstrate that annual applications of agricultural limestone on acid soils of the maritime Pacific Northwest of the United States can enhance suppression of spinach Fusarium wilt, potentially reducing the required rotation interval by as much as 50%, thereby doubling the capacity for spinach seed production in the United States.
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Zhou, Cheng, Zhongyou Ma, Xiaoming Lu, Lin Zhu e Jianfei Wang. "Phenolic Acid-Degrading Consortia Increase Fusarium Wilt Disease Resistance of Chrysanthemum". Agronomy 10, n.º 3 (12 de março de 2020): 385. http://dx.doi.org/10.3390/agronomy10030385.
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Soil microbial community changes imposed by the cumulative effects of root-secreted phenolic acids (PAs) promote soil-borne pathogen establishment and invasion under monoculture systems, but the disease-suppressive soil often exhibits less soil-borne pathogens compared with the conducive soil. So far, it remains poorly understood whether soil disease suppressiveness is associated with the alleviated negative effects of PAs, involving microbial degradation. Here, the long-term monoculture particularly shaped the rhizosphere microbial community, for example by the enrichment of beneficial Pseudomonas species in the suppressive soil and thus enhanced disease-suppressive capacity, however this was not observed for the conducive soil. In vitro PA-degradation assays revealed that the antagonistic Pseudomonas species, together with the Xanthomonas and Rhizobium species, significantly increased the efficiency of PA degradation compared to single species, at least partially explaining how the suppressive soil accumulated lower PA levels than the conducive soil. Pot experiments further showed that this consortium harboring the antagonistic Pseudomonas species can not only lower PA accumulation in the 15-year conducive soils, but also confer stronger Fusarium wilt disease suppression compared with a single inoculum with the antagonistic bacteria. Our findings demonstrated that understanding microbial community functions, beyond the single direct antagonism, facilitated the construction of active consortia for preventing soil-borne pathogens under intensive monoculture.
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Starr, Robyn, e Douglas J. Hilton. "SOCS: suppressors of cytokine signalling". International Journal of Biochemistry & Cell Biology 30, n.º 10 (outubro de 1998): 1081–85. http://dx.doi.org/10.1016/s1357-2725(98)00067-3.
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Watson, Tristan T., Tom A. Forge e Louise M. Nelson. "Pseudomonads contribute to regulation ofPratylenchus penetrans(Nematoda) populations on apple". Canadian Journal of Microbiology 64, n.º 11 (novembro de 2018): 775–85. http://dx.doi.org/10.1139/cjm-2018-0040.
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Inoculation with antagonistic soil microorganisms has shown potential to suppress replant disease of apple in orchard soils. Pseudomonas spp. may have the potential to reduce Pratylenchus penetrans populations on apple. Pseudomonas spp. were isolated from the rhizosphere of sweet cherry and screened for antagonistic characteristics. Two highly antagonistic Pseudomonas isolates, P10-32 and P10-42, were evaluated for growth promotion of apple seedlings, suppression of P. penetrans populations, and root colonization in soil from three orchards. During the isolate screening, Pseudomonas fluorescens P10-32 reduced in vitro growth of fungal pathogens, had protease activity, had capacity to produce pyrrolnitrin, suppressed P. penetrans populations, and increased plant biomass. Pseudomonas fluorescens P10-42 reduced in vitro growth of fungal pathogens, had protease activity, suppressed P. penetrans populations, and increased plant biomass. In potted orchard soil, inoculating apple with P. fluorescens P10-32 suppressed P. penetrans populations in one of the three soils examined. Inoculation with P. fluorescens P10-42 improved plant growth in two of the soils and suppressed P. penetrans abundance in one soil. In one of the soils, P. fluorescens P10-42 was detected on the roots 56 days postinoculation. Overall, we conclude that Pseudomonas spp. play a role in suppressing P. penetrans on apple in orchard soil.
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Pinsky, Benjamin A., Chitra V. Kotwaliwale, Sean Y. Tatsutani, Christopher A. Breed e Sue Biggins. "Glc7/Protein Phosphatase 1 Regulatory Subunits Can Oppose the Ipl1/Aurora Protein Kinase by Redistributing Glc7". Molecular and Cellular Biology 26, n.º 7 (1 de abril de 2006): 2648–60. http://dx.doi.org/10.1128/mcb.26.7.2648-2660.2006.
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ABSTRACT Faithful chromosome segregation depends on the opposing activities of the budding yeast Glc7/PP1 protein phosphatase and Ipl1/Aurora protein kinase. We explored the relationship between Glc7 and Ipl1 and found that the phosphorylation of the Ipl1 substrate, Dam1, was altered by decreased Glc7 activity, whereas Ipl1 levels, localization, and kinase activity were not. These data strongly suggest that Glc7 ensures accurate chromosome segregation by dephosphorylating Ipl1 targets rather than regulating the Ipl1 kinase. To identify potential Glc7 and Ipl1 substrates, we isolated ipl1-321 dosage suppressors. Seven genes (SDS22, BUD14, GIP3, GIP4, SOL1, SOL2, and PEX31) encode newly identified ipl1 dosage suppressors, and all 10 suppressors encode proteins that physically interact with Glc7. The overexpression of the Gip3 and Gip4 suppressors altered Glc7 localization, indicating they are previously unidentified Glc7 regulatory subunits. In addition, the overexpression of Gip3 and Gip4 from the galactose promoter restored Dam1 phosphorylation in ipl1-321 mutant cells and caused wild-type cells to arrest in metaphase with unsegregated chromosomes, suggesting that Gip3 and Gip4 overexpression impairs Glc7's mitotic functions. We therefore propose that the overexpression of Glc7 regulatory subunits can titrate Glc7 away from relevant Ipl1 targets and thereby suppress ipl1-321 cells by restoring the balance of phosphatase/kinase activity.
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Lee, Choong-Eun, e Seol-Hee Kim. "Down-regulation of ROS-mediated T cell signaling leading to IL-4 production by SOCS targeting ATFII and STAT6 (163.6)". Journal of Immunology 188, n.º 1_Supplement (1 de maio de 2012): 163.6. http://dx.doi.org/10.4049/jimmunol.188.supp.163.6.
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Abstract Suppressors of cytokine signaling (SOCS) have emerged as multiple role players in the regulation of immune signaling pathways. We have recently reported that SOCS1 suppresses ROS-mediated T cell apoptosis through the induction of thioredoxin which down-regulates intracellular ROS levels and protects protein tyrosine phosphatases (Oncogene 28:3145, 2009). In the present study we have investigated the role of SOCS in ROS-mediated T cell differentiation leading to Th1/Th2 cytokine production. Both in Jurkat T cell lines and mouse splenocytes, mild oxidative stress stimulated TCR-mediated cytokine production toward Th2 differentiation: A prominent induction of IL-4 gene expression was noted without notable effects on IFN-r. Such ROS-stimulated TCR signaling for IL-4 induction was mediated by activation of Jak1/STAT6 and p38/ATFII. Introduction and overexpression of SOCS1 and SOCS3 in Jurkat T cells significantly reduced ROS/TCR-mediated IL-4 gene induction with a concomitant inhibition on ATFII and STAT6 pathways. Under this condition SOCS substantially attenuated TCR/H2O2 -induced intracellular ROS levels, suggesting that ROS-scavenging function of SOCS affects TCR signaling leading to IL-4 gene expression. Since we have previously identified human thioredoxin as a Th1-inducing factor in T cells (BMC Immunol 9:64, 2008), the role of thioredoxin in SOCS-mediated down-regulation of Th2 response in conjunction with the regulation of NADPH-oxidase system is under investigation.
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Masuzaki, Ryota, Tatsuo Kanda, Reina Sasaki, Naoki Matsumoto, Kazushige Nirei, Masahiro Ogawa, Seth J. Karp, Mitsuhiko Moriyama e Hirofumi Kogure. "Suppressors of Cytokine Signaling and Hepatocellular Carcinoma". Cancers 14, n.º 10 (22 de maio de 2022): 2549. http://dx.doi.org/10.3390/cancers14102549.
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Cytokines are secreted soluble glycoproteins that regulate cellular growth, proliferation, and differentiation. Suppressors of cytokine signaling (SOCS) proteins negatively regulate cytokine signaling and form a classical negative feedback loop in the signaling pathways. There are eight members of the SOCS family. The SOCS proteins are all comprised of a loosely conserved N-terminal domain, a central Src homology 2 (SH2) domain, and a highly conserved SOCS box at the C-terminus. The role of SOCS proteins has been implicated in the regulation of cytokines and growth factors in liver diseases. The SOCS1 and SOCS3 proteins are involved in immune response and inhibit protective interferon signaling in viral hepatitis. A decreased expression of SOCS3 is associated with advanced stage and poor prognosis of patients with hepatocellular carcinoma (HCC). DNA methylations of SOCS1 and SOCS3 are found in HCC. Precise regulation of liver regeneration is influenced by stimulatory and inhibitory factors after partial hepatectomy (PH), in particular, SOCS2 and SOCS3 are induced at an early time point after PH. Evidence supporting the important role of SOCS signaling during liver regeneration also supports a role of SOCS signaling in HCC. Immuno-oncology drugs are now the first-line therapy for advanced HCC. The SOCS can be potential targets for HCC in terms of cell proliferation, cell differentiation, and immune response. In this literature review, we summarize recent findings of the SOCS family proteins related to HCC and liver diseases.
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Ghini, Raquel, e Marcelo Augusto Boechat Morandi. "Biotic and abiotic factors associated with soil suppressiveness to Rhizoctonia solani". Scientia Agricola 63, n.º 2 (abril de 2006): 153–60. http://dx.doi.org/10.1590/s0103-90162006000200007.
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Crop management may modify soil characteristics, and as a consequence, alter incidence of diseases caused by soilborne pathogens. This study evaluated the suppressiveness to R. solani in 59 soil samples from a microbasin. Soil sampling areas included undisturbed forest, pasture and fallow ground areas, annual crops, perennial crops, and ploughed soil. The soil samples were characterized according to abiotic variables (pH; electrical conductivity; organic matter content; N total; P; K; Ca; Mg; Al; H; S; Na; Fe; Mn; Cu; Zn; B; cation exchange capacity; sum of bases and base saturation) and biotic variables (total microbial activity evaluated by the CO2 evolution and fluorescein diacetate hydrolysis; culturable bacterial, fungal, actinomycetes, protozoa, fluorescent Pseudomonas and Fusarium spp. communities). The contribution and relationships of these variables to suppression to R. solani were assessed by path analysis. When all samples were analyzed together, only abiotic variables correlated with suppression of R. solani, but the entire set of variables explained only 51% of the total variation. However, when samples were grouped and analyzed by vegetation cover, the set of evaluated variables in all cases accounted for more than 90% of the variation in suppression of the pathogen. In highly suppressive soils of forest and pasture/fallow ground areas, several abiotic variables and fluorescein diacetate hydrolysis correlated with suppression of R. solani and the set of variables explained more than 98% of suppressiveness.