Introduction Leaf rust, caused by Puccinia triticina, inflicts 10-50% yield losses in bread wheat, with newly emerging virulent pathotypes overcoming major Lr genes and rendering the cultivars susceptible. The identification of genetic loci conferring resistance to wheat leaf rust, coupled with the development of molecular markers and the incorporation of resistant alleles into breeding programs, represents the most sustainable and cost-effective strategy for disease management. Methods The present study, employed a recombinant inbred line population derived from (PBW343/W8627) was utilized to map QTLs for leaf rust resistance at seedling and adult plant stages. The RIL population along with its parents was evaluated at seedling and adult plant stages against most prevalent and virulent pathotypes at seedling and adult plant stages for the two crop seasons (2021-22 and 2022-23). Result Analysis of variance revealed significant differences among the RILs across years. For QTL mapping, genotyping was conducted using 3.9K DArT SNPs leading to the identification of two QTLs: QLr.iiwbr.2B.1 (2B) explaining phenotypic variance of 13.26% with a LOD score 8 and QLr.iiwbr.5B.1 (5B) explaining 14.91% with LOD score 3.91 for all stage resistance (ASR) as well as one QTL for adult plant resistance (APR), QLr.iiwbr.6B.1 (PVE 14.21%). Further, in silico analysis revealed a putative candidate gene encoding for Annexin (TraesCS5B02G201700) which plays an important role in disease resistance in wheat. Discussion The study identified new QTLs associated with leaf rust resistance, providing valuable sources to accelerate the development of durable rust resistant sources. Further, characterization of these QTLs will strengthen their utility in rust resistance breeding.
Wheat (Triticum aestivum L.) is an economically important cereal crop. Its genetic diversity is a prerequisite for successful breeding for resistance to leaf and stem rust, as well as for other important traits. Therefore, the main objective of the study was to determine the level of genetic diversity of a file of 185 wheat accessions chosen to represent a wide range of resistance levels to leaf and stem rusts. They were evaluated at two locations in three years (2023–2025) for leaf and stem rust resistance by means of visual evaluation and fungus content using real-time PCR. BLUP values were then computed from these multi-environmental data. In addition, data on other traits such as heading time, plant height, and grain quality were collected. In the PCA, grain quality variables represented the first factor, explaining 41% of the total variability. Rust resistance was mainly associated with the second and the third factor. Population analysis revealed primary two (K = 2) and secondary six (K = 6) clusters, computed by using 13,274 DArT markers. The correlation between genotype and phenotype data was high (R = 0.89) when all traits were analyzed, and lower (R = 0.58) when only leaf and stem rust resistance variables were considered. Genetic diversity was also studied through an association analysis between markers and phenotypic traits using GLMs and MLMs. As a result, 300 statistically significant marker-trait associations (MTAs) were identified (p ≤ 3.77 × 10−6). Of these MTAs, 180 were associated with rust resistance variables and 120 with other traits. A BLAST search of rust resistance MTAs identified 128 putative genes; 47 of them can be taken for candidate genes related to fungal resistance. The results show that association analysis can help to explain the genetic diversity of selected wheat accessions, and that leaf and stem rust resistance are complex traits involving many non-specific resistance genes.
Leona Leišová-Svobodová, Stanislav Ježek, O. Veškrna et al.· Agronomy· 0 citations
Soybean root rot caused by Fusarium graminearum is an important soil-borne disease. It hinders seedling establishment and ultimately reduces soybean yield. Resistant germplasm and reliable molecular markers are therefore needed for resistance breeding. In this study, 336 soybean accessions were evaluated for resistance to F. graminearum root rot using the disease severity index (DSI), which ranged from 5.71 to 100.00 across the association panel. Genome-wide association analysis was performed using resequencing-based single nucleotide polymorphism (SNP) data with mixed linear model (MLM) and Fixed and random model Circulating Probability Unification (FarmCPU) models, which detected 117 and 113 candidate resistance-associated SNPs, respectively. Among these, 105 shared SNPs were used to define candidate genomic intervals containing 247 annotated genes. Based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, functional annotation, and allelic-effect analysis, six candidate genes and their associated exonic SNPs were prioritized. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed infection-responsive expression patterns for all six candidate genes, with Glyma.17g202500 and Glyma.18g266700 showing stronger induction in the resistant accession. Two SNPs in these genes were converted into Kompetitive allele-specific PCR (KASP) assays. KASP-S17_32244510 and KASP-S18_55105706 were successfully developed for genotype screening, with screening efficiencies of 73.08% and 74.29%, respectively. These findings identify useful genetic targets and molecular markers for improving soybean resistance to root rot caused by F. graminearum.
These findings uncover new QTLs for PM resistance in strawberry, including on fruit, and provide validated strategies for breeding disease-resistant cultivars.
Alexandre Prohaska, Pol Rey-Serra, J. Bénéjam et al.· Horticulture Research· 0 citations