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.

Resistance to Puccinia recondita f. sp. tritici in 50 Mexican bread wheat cultivars

Abstract: Bread wheat (Triticum aestivum L.) cultivars derived from CIM-MYT germplasm are currently grown on a large area worldwide. Since limited information is available on genes for resistance to leaf rust in these wheats, the two main objectives of the study were to postulate the known Lr genes conferring low seeding reactions to 18 pathotypes of Puccinia recondita Roberge ex Desmaz. f. sp. tritici in 50 Mexican cultivars released between 1960 and 1988; and to evaluate the presence of additional adult-plant resistance

Endophytic fungi promote plant growth and mitigate the adverse effects of stem rot: an example of Penicillium citrinum and Aspergillus terreus

Abstract: Disease resistance is a highly desirable crop trait in the sustainable agricultural industry. Endophytic fungi with gibberellins-secreting potential are now widely known for their ability to stimulate plant growth, but their role in promoting disease resistance in plants has rarely been reported. We have studied the role of Penicillium citrinum LWL4 and Aspergillus terreus LWL5 in time-dependent manner on sunflower (Helianthus annuus L.) growth, disease resistance and their capacity for the regulation of hormone signaling networks involved in plant defense against the stem rot caused by Sclerotium rolfsii for 3, 6 and 12 days after treatment (DAT). Our results show that plant growth characteristics (i.e. shoot length, shoot diameter, shoot fresh/dry weight, transpiration, stomatal conductance, photosynthesis and chlorophyll content) were promoted in fungi-treated plants with or without the disease caused by Sclerotium rolfsii as compared to their respective controls in 3, 6 and 12 DAT. The negative impact...

Genome Wide Association Study of Seedling and Adult Plant Leaf Rust Resistance in Elite Spring Wheat Breeding Lines.

Abstract: Leaf rust is an important disease, threatening wheat production annually. Identification of resistance genes or QTLs for effective field resistance could greatly enhance our ability to breed durably resistant varieties. We applied a genome wide association study (GWAS) approach to identify resistance genes or QTLs in 338 spring wheat breeding lines from public and private sectors that were predominately developed in the Americas. A total of 46 QTLs were identified for field and seedling traits and approximately 20–30 confer field resistance in varying degrees. The 10 QTLs accounting for the most variation in field resistance explained 26–30% of the total variation (depending on traits: percent severity, coefficient of infection or response type). Similarly, the 10 QTLs accounting for most of the variation in seedling resistance to different races explained 24–34% of the variation, after correcting for population structure. Two potentially novel QTLs (QLr.umn-1AL, QLr.umn-4AS) were identified. Identification of novel genes or QTLs and validation of previously identified genes or QTLs for seedling and especially adult plant resistance will enhance understanding of leaf rust resistance and assist breeding for resistant wheat varieties. We also developed computer programs to automate field and seedling rust phenotype data conversions. This is the first GWAS study of leaf rust resistance in elite wheat breeding lines genotyped with high density 90K SNP arrays.

Functional roles of the pepper pathogen-induced bZIP transcription factor, CAbZIP1, in enhanced resistance to pathogen infection and environmental stresses

Abstract: Transcription factors often belong to multigene families and their individual contribution in a particular regulatory network remains difficult to assess. We identify and functionally characterize the pepper bZIP transcription factor CAbZIP1 gene isolated from pepper leaves infected with Xanthomonas campestris pv. vesicatoria. Transient expression analysis of the CAbZIP1–GFP fusion protein in Arabidopsis protoplasts revealed that the CAbZIP1 protein is localized in the nucleus. The N-terminal region of CAbZIP1 fused to the GAL4 DNA-binding domain is required to activate transcription of reporter genes in yeast. The CAbZIP1 transcripts are constitutively expressed in the pepper root and flower, but not in the leaf, stem and fruit. The CAbZIP1 gene is locally or systemically induced in pepper plants infected by either X. campestris pv. vesicatoria or Pseudomonas fluorescens. The CAbZIP1 gene is also induced by abiotic elicitors and environmental stresses. The CAbZIP1 transgenic Arabidopsis exhibits a dwarf phenotype, indicating that CAbZIP1 may be involved in plant development. The CAbZIP1 overexpression in the transgenic Arabidopsis plants confers enhanced resistance to Pseudomonas syringae pv. tomato DC3000, accompanied by expression of the AtPR-4 and AtRD29A. The transgenic plants also exhibit increased drought and salt tolerance during all growth stages. Moreover, the transgenic plants are tolerant to methyl viologen-oxidative stress. Together, these data suggest that the CAbZIP1 transcription factor function as a possible regulator in enhanced disease resistance and environmental stress tolerance.

Molecular genetics of race non-specific rust resistance in wheat

Abstract: Over 150 resistance genes that confer resistance to either leaf rust, stripe rust or stem rust have been catalogued in wheat or introgressed into wheat from related species. A few of these genes from the ‘slow-rusting’ adult plant resistance (APR) class confer partial resistance in a race non-specific manner to one or multiple rust diseases. The recent cloning of two of these genes, Lr34/Yr18, a dual APR for leaf rust and stripe rust, and Yr36, a stripe rust APR gene, showed that they differ from other classes of plant resistance genes. Currently, seven Lr34/Yr18 haplotypes have been identified from sequencing the encoding ATP Binding Cassette transporter gene from diverse wheat germplasm of which one haplotype is commonly associated with the resistance phenotype. The paucity of well characterised APR genes, particularly for stem rust, calls for a focused effort in developing critical genetic stocks to delineate quantitative trait loci, construct specific BAC libraries for targeted APR genes to facilitate robust marker development for breeding applications, and the eventual cloning of the encoding genes.