Hakyung Kwon, Moon Young Kim, Xuefei Yang & Suk-Ha Lee

Theoretical and Applied genetics; April 2024; vol. 137; article 85

Key message

A stable QTL qSW_Gm10 works with a novel locus, qSW_Gm01, in a synergistic manner for controlling slow-wilting traits at the early vegetative stage under drought stress in soybean.

Abstract

Drought is one of the major environmental factors which limits soybean yield. Slow wilting is a promising trait that can enhance drought resilience in soybean without additional production costs. Recently, a Korean soybean cultivar SS2-2 was reported to exhibit slow wilting at the early vegetative stages. To find genetic loci responsible for slow wilting, in this study, quantitative trait loci (QTL) analysis was conducted using a recombinant inbred line (RIL) population derived from crossing between Taekwangkong (fast-wilting) and SS2-2 (slow-wilting). Wilting score and leaf moisture content were evaluated at the early vegetative stages for three years. Using the ICIM-MET module, a novel QTL on Chr01, qSW_Gm01 was identified, together with a previously known QTL, qSW_Gm10. These two QTLs were found to work synergistically for slow wilting of the RILs under the water-restricted condition. Furthermore, the SNP markers from the SoySNP50K dataset, located within these QTLs, were associated with the wilting phenotype in 30 diverse soybean accessions. Two genes encoding protein kinase 1b and multidrug resistance-associated protein 4 were proposed as candidate genes for qSW_Gm01 and qSW_Gm10, respectively, based on a comprehensive examination of sequence variation and gene expression differences in the parental lines under drought conditions. These genes may play a role in slow wilting by optimally regulating stomatal aperture. Our findings provide promising genetic resources for improving drought resilience in soybean and give valuable insights into the genetic mechanisms governing slow wilting.

See https://link.springer.com/article/10.1007/s00122-024-04585-1

Fig. 7

Identifcation of Glyma.10G019000 as a putative candidate gene for qSW_Gm10. a DNA sequence variants (upper) and amino acid change (lower) of Glyma.10G019000. In the gene structure (the upper diagram), yellow rounded rectangle, blue rectangle and black line represent CDS, UTR and intron, respectively. For the protein structure (the lower diagram), fve transmembrane regions, two ABC_membrane domains and two ATPases associated with a variety of cellular activities (AAA) domains are detected from the TMHMM v2.0 program, Pfam and SMART database, respectively. b Phylogenetic tree of homologs of Glyma.10G019000 in Arabidopsis and soybean. c Gene structure of Glyma.10G019000 and its homologs d Expression level of Glyma.10G019000 and its paralogs under control and drought condition. The expression level of Arabidopsis orthologs of Glyma.10G019000 is not shown