Genomic Polymorphism Identifies a Subtilisin‐Like Protease near the Rhg4 Locus in Soybean

Abstract

Soybean [Glycine max (L.) Merr.] germplasm PI 437654 exhibits broad resistance to soybean cyst nematode (Heterodera glycines Ichinohe, SCN). Probes derived from PI 437654 bacterial artificial chromosome (BAC) clone 15G19 at the Rhg4 locus detected a restriction fragment length polymorphism (RFLP) between resistant and susceptible germplasms. Detailed RFLP analysis using restriction fragments from BAC clone 15G19 associated the polymorphism with an 8‐kb BamHI fragment containing the promoter region and partial coding sequence of a novel soybean subtilisin‐like protease, GmSUB1 Complete sequence of GmSUB1 was determined (GenBank ). Regulatory elements for root gene expression, pathogen response, coordinated multiple‐gene expression, and a novel 90‐bp direct repeat were identified. GmSUB1 shows 74% similarity to Arabidopsis thaliana AIR3. Hybridization analyses indicate that PI 437654 contains only full‐length copies of GmSUB1, whereas susceptible germplasm ‘Williams 82’ contains both full‐length and truncated copies of the gene. A 4‐fold increase in GmSUB1 copy number, and a corresponding 2‐ to 3‐fold increase in steady state GmSUB1 mRNA levels, was observed in PI 437654 compared with Williams 82. Localization and polymorphism of GmSUB1 within the Rhg4 resistance region, and increases in GmSUB1 gene copy number and expression in PI 437654 compared with Williams 82 infers a functional role in the pathogen response. GmSUB1 is believed to be secreted into the extracellular matrix, and may function in reorganization of cell wall components during plant development and in the defense response.

Identification and mapping of quantitative trait loci (QTL) conferring resistance to Fusarium graminearum from soybean PI 567301B

“…RALF peptides are present throughout the plant kingdom and have been shown to cause a loss of root growth inhibition in tomato seedlings (Pearce et al 2010 ). Two genes encoding subtilisin-like proteases are also located within the region, which have a predicted function in recognition of cell wall components during the plant development and in the plant defense responses (Nelsen et al 2004 ). Another candidate for a defense response is a gene encoding a brassinosteroid-regulated protein, which regulates the gene expression and promotes elongation in soybean (Zurek and Clouse 1994 ).…”

Structural Features of the Endogenous CHS Silencing and Target Loci in the Soybean Genome

“…4). Th e 5000 bases on the complementary strand of BAC77G7-a from base 55,688 to 60,687 exhibit a 99% sequence identity with the 5′ end of the GenBank entry AY277949, a soybean subtilisin-like protease (GmSUB1, Nelsen et al, 2004). However, relative to the 11 exons that constitute the 9471 bases of the full-length AY277949, the homologous sequence on BAC77G7-a extends from the 5′ untranslated region (UTR) until part of the fourth intron only.…”

“…Furthermore, it appears that relative to AY277949 (GmSUB1), both the full-length and the truncated subtilisin on our two BAC clones carry an identical insertion of 814 bases in the 5′ UTR (bases 39,874-40,688 on BAC27P17 and bases 59,273-60,087 on BAC77G7-a). Th is insertion could probably be explained by a varietal diff erence in the sequences of subtilisin since GmSUB1 is from the PI437654 line (Nelsen et al, 2004) and not Williams.…”

Understanding Root Rot Disease in Agricultural Crops

“…In addition, there were three rapid alkanization factor (RALF) genes that can initiate a signal transduction pathway and two genes coding for subtilisin-like proteases. Subtilisin proteases are believed to be secreted into the extracellular matrix and function to reorganize cell wall components during defense response [113,314]. A subsequent study identified four differentially expressed genes that mapped to this QTL located on chromosome 8.…”