Severe southern soybean crinkle leaf disease (SSCLD) reduces soybean seed yield by approximately 40%. Identifying the genes that control SSCLD is crucial for breeding resistant varieties and elucidating the molecular mechanisms underlying SSCLD infection. In this study, recombinant inbred lines (RILs, n = 236) derived from a cross between Nannong1138-2 (NN1138-2) and Zhengxiaodou (ZXD) were used as experimental materials. A field trial employing a randomized block design was conducted in four environments across two locations, Nanning (2019–2021) and Du’an (2020) in Guangxi, to identify the disease severity grades of SSCLD in the field. QTLs controlling SSCLD were detected via a genetic map constructed using 3255 SLAF (specific locus amplified fragment) markers from the recombinant inbred lines. RT‒qPCR was used to analyze candidate gene expression at major effect loci. The results revealed that eight SSCLD-associated QTLs were identified on chromosomes 3, 6, 12, and 17. Notably, the qw12-1 locus on chromosome 12 was detected across three developmental stages in three of the four environments, explaining 10. 18–58. 20% of the phenotypic variation. RT‒qPCR analysis of 12 disease resistance-related genes within the qw12-1 interval revealed that GLYMA₁2G233000 and GLYMA₁2G239200 presented significantly higher expression in crinkled leaf lines than in normal leaf lines during the V5 (fifth trifoliolate stage), R2 (full bloom stage), and R6 (full seed stage) stages. These genes were prioritized as potential prime candidates for SSCLD resistance genes. This research provides foundational data for the fine mapping of qw12-1 and cloning SSCLD-related genes, advancing our understanding of the molecular mechanisms underlying SSCLD.
Chen et al. (Wed,) studied this question.