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Plant disease resistance

About: Plant disease resistance is a research topic. Over the lifetime, 12952 publications have been published within this topic receiving 381820 citations. The topic is also known as: plant innate immunity.


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Journal ArticleDOI
TL;DR: It is shown that transgenic virus resistance in sugarcane (Saccharum spp. hybrid) is based on posttranscriptional gene silencing, and increased DNA methylation was observed in the transcribed region of the CP transgenes in most of these plants, indicating that an RNA-mediated, homology-dependent mechanism is at the base of the virus resistance.
Abstract: RNA-mediated, posttranscriptional gene silencing has been determined as the molecular mechanism underlying transgenic virus resistance in many plant virus-dicot host plant systems. In this paper we show that transgenic virus resistance in sugarcane (Saccharum spp. hybrid) is based on posttranscriptional gene silencing. The resistance is derived from an untranslatable form of the sorghum mosaic potyvirus strain SCH coat protein (CP) gene. Transgenic sugarcane plants challenged with sorghum mosaic potyvirus strain SCH had phenotypes that ranged from fully susceptible to completely resistant, and a recovery phenotype was also observed. Clones derived from the same transformation event or obtained after vegetative propagation could display different levels of virus resistance, suggesting the involvement of a quantitative component in the resistance response. Most resistant plants displayed low or undetectable steady-state CP transgene mRNA levels, although nuclear transcription rates were high. Increased DNA methylation was observed in the transcribed region of the CP transgenes in most of these plants. Collectively, these characteristics indicate that an RNA-mediated, homology-dependent mechanism is at the base of the virus resistance. This work extends posttranscriptional gene silencing and homology-dependent virus resistance, so far observed only in dicots, to an agronomically important, polyploid monocot.

174 citations

Journal ArticleDOI
TL;DR: A large S. chilense introgression spanning markers from C2_At2g39690 to T0834 in LA2779-derived advanced breeding lines resistant to both TYLCV and ToMoV is identified, suggesting the possible coexistence and linkage of resistance alleles at both Ty-1 and Ty-3 loci in these lines.
Abstract: Resistance to begomoviruses including bipartite Tomato mottle virus (ToMoV) and monopartite Tomato yellow leaf curl virus (TYLCV) has been introgressed to cultivated tomato (Solanum lycopersicum) from S. chilense accessions LA1932, LA2779, and LA1938. Previous research demonstrated that three regions on chromosome 6 were associated with the resistance, two of which were required for a line to provide a high level of resistance. In the present study, we identified a large S. chilense introgression spanning markers from C2_At2g39690 to T0834 in LA2779-derived advanced breeding lines resistant to both TYLCV and ToMoV. A begomovirus resistance locus, Ty-3, was mapped to the marker interval between cLEG-31-P16 and T1079 on the long arm of chromosome 6. In addition to the Ty-3 locus, the large introgression also spans the Ty-1 region near the Mi gene, suggesting the possible coexistence and linkage of resistance alleles at both Ty-1 and Ty-3 loci in these lines. In contrast, LA1932-derived advanced breeding lines possess a much shorter introgression from cLEG-31-P16 to C2_At5g41480, which also carries a begomovirus resistance locus that is probably allelic at the Ty-3 locus. The PCR-based markers tightly linked to the Ty-3 locus as well as the markers near the Ty-1 region have been used in our breeding program for efficient selection of begomovirus resistance in the past three growing seasons and will be useful resources for tomato breeders around the world.

173 citations

Journal ArticleDOI
TL;DR: AvrStb6 is the first avirulence gene to be functionally validated in Z. tritici, contributing to the understanding ofAvirulence in apoplastic pathogens and the mechanisms underlying GFG interactions between Z.Tritici and wheat.
Abstract: Zymoseptoria tritici is the causal agent of Septoria tritici blotch, a major pathogen of wheat globally and the most damaging pathogen of wheat in Europe. A gene-for-gene (GFG) interaction between Z. tritici and wheat cultivars carrying the Stb6 resistance gene has been postulated for many years, but the genes have not been identified. We identified AvrStb6 by combining quantitative trait locus mapping in a cross between two Swiss strains with a genome-wide association study using a natural population of c. 100 strains from France. We functionally validated AvrStb6 using ectopic transformations. AvrStb6 encodes a small, cysteine-rich, secreted protein that produces an avirulence phenotype on wheat cultivars carrying the Stb6 resistance gene. We found 16 nonsynonymous single nucleotide polymorphisms among the tested strains, indicating that AvrStb6 is evolving very rapidly. AvrStb6 is located in a highly polymorphic subtelomeric region and is surrounded by transposable elements, which may facilitate its rapid evolution to overcome Stb6 resistance. AvrStb6 is the first avirulence gene to be functionally validated in Z. tritici, contributing to our understanding of avirulence in apoplastic pathogens and the mechanisms underlying GFG interactions between Z. tritici and wheat.

173 citations

Journal ArticleDOI
TL;DR: A cleaved amplified polymorphic sequence (CAPS) marker is developed that is associated with the presence or absence of the Sr2 gene in 115 of 122 diverse wheat lines and provides breeders with a selection tool for one of the most important disease resistance genes of wheat.
Abstract: The stem rust resistance gene Sr2 has provided broad-spectrum protection against stem rust (Puccinia graminis Pers. f. sp. tritici) since its wide spread deployment in wheat from the 1940s. Because Sr2 confers partial resistance which is difficult to select under field conditions, a DNA marker is desirable that accurately predicts Sr2 in diverse wheat germplasm. Using DNA sequence derived from the vicinity of the Sr2 locus, we developed a cleaved amplified polymorphic sequence (CAPS) marker that is associated with the presence or absence of the gene in 115 of 122 (95%) diverse wheat lines. The marker genotype predicted the absence of the gene in 100% of lines which were considered to lack Sr2. Discrepancies were observed in lines that were predicted to carry Sr2 but failed to show the CAPS marker. Given the high level of accuracy observed, the marker provides breeders with a selection tool for one of the most important disease resistance genes of wheat.

173 citations

Journal ArticleDOI
TL;DR: Treatment with any of the cinnamyl-alcohol dehydrogenase inhibitors decreased the frequency of lignified necrotic host cells and concomitantly led to increased fungal growth, pointing to a causal relationship between the formation of lIGNin precursors and the resistance of wheat to stem rust.
Abstract: When highly resistant wheat (Triticum aestivum L.) varieties are infected by an avirulent race of the stem rust fungus (Puccinia graminis Pers. f. sp. tritici Erics. and E. Henn.), penetrated host cells undergo rapid necrotization. This hypersensitive cell death is correlated with cellular lignification which efficiently restricts further fungal growth. Three competitive inhibitors of phenylalanine ammonia-lyase, the first enzyme of the general phenylpropanoid pathway and, thus, of lignin biosynthesis, namely α-aminooxyacetate, α-aminooxy-β-phenylpropionic acid, and (1-amino-2-phenylethyl)phosphonic acid, and two highly specific irreversible suicide inhibitors of the lignification-specific enzyme cinnamyl-alcohol dehydrogenase, namely N(O-aminophenyl)sulfinamoyl-tertiobutyl acetate and N(O-hydroxyphenyl)sulfinamoyl-tertiobutyl acetate, were applied to genetically resistant wheat plants prior to inoculation with stem rust. Treatment with any of these inhibitors decreased the frequency of lignified necrotic host cells and concomitantly led to increased fungal growth. The cinnamyl-alcohol dehydrogenase inhibitors were generally more effective than the phenylalanine ammonia-lyase inhibitors, occasionally allowing some sporulation to occur on the resistant wheat leaves. These results clearly point to a causal relationship between the formation of lignin precursors and the resistance of wheat to stem rust.

172 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023377
2022756
2021410
2020438
2019526
2018640