R_SC3K of soybean cv. Kefeng No.1 confers resistance to soybean mosaic virus by interacting with the viral protein P3

Abstract

Soybean mosaic virus (SMV) is one of the most devastating viral pathogens of soybean (Glycine max (L.) Merr). In total, 22 Chinese SMV strains (SC1–SC22) have been classified based on the responses of 10 soybean cultivars to these pathogens. However, although several SMV‐resistance loci in soybean have been identified, no gene conferring SMV resistance in the resistant soybean cultivar (cv.) Kefeng No.1 has been cloned and verified. Here, using F2‐derived F3 (F2:3) and recombinant inbred line (RIL) populations from a cross between Kefeng No.1 and susceptible soybean cv. Nannong 1138‐2, we localized the gene in Kefeng No.1 that mediated resistance to SMV‐SC3 strain to a 90‐kb interval on chromosome 2. To study the functions of candidate genes in this interval, we performed Bean pod mottle virus (BPMV)‐induced gene silencing (VIGS). We identified a recombinant gene (which we named RSC3K) harboring an internal deletion of a genomic DNA fragment partially flanking the LOC100526921 and LOC100812666 reference genes as the SMV‐SC3 resistance gene. By shuffling genes between infectious SMV DNA clones based on the avirulent isolate SC3 and virulent isolate 1129, we determined that the viral protein P3 is the avirulence determinant mediating SMV‐SC3 resistance on Kefeng No.1. P3 interacts with RNase proteins encoded by RSC3K, LOC100526921, and LOC100812666. The recombinant RSC3K conveys much higher anti‐SMV activity than LOC100526921 and LOC100812666, although those two genes also encode proteins that inhibit SMV accumulation, as revealed by gene silencing in a susceptible cultivar and by overexpression in Nicotiana benthamiana. These findings demonstrate that RSC3K mediates the resistance of Kefeng No.1 to SMV‐SC3 and that SMV resistance of soybean is determined by the antiviral activity of RNase proteins.

Development of an NLR-ID Toolkit and Identification of Novel Disease-Resistance Genes in Soybean

“…Broad-spectrum resistance refers to the resistance of a cultivar or a gene to two or more pathogens or the majority of races/isolates of the same pathogen [ 54 , 55 ]. Soybean is an important economic oil crop, but it is susceptible to various viruses [ 56 ]. Therefore, the mining of broad-spectrum resistance genes is of great significance.…”

WGCNA Reveals Hub Genes and Key Gene Regulatory Pathways of the Response of Soybean to Infection by Soybean mosaic virus

“…Based on the interaction between viruses and plants, the types of plant resistance to viruses are thought to include dominant resistance and recessive resistance [14,15]. To our knowledge, approximately 34 single dominant resistance loci for SMV located on six chromosomes have been identified and reported in soybean: chromosome 02 (Rsv4, RSC5, RSC6, RSC7, RSC8, RSC10, RSC17, RSC18A, RSC3(w), RkSC13, Rsc13, RSC9, and Rsc3k) [16][17][18][19][20][21], chromosome 03 (qTsmv-13) [22], chromosome 06 (RSC15, RSC18) [2,20], chromosome 11(RSMV-11) [23], chromosome 13 (Rsv1, Rsv5, RSC3Q, RSC11, RSC12, RSC14Q, RSC18B, RSC20, RSC-pm, RSC-ps, Rsv1-r, RSC15ZH, qSMV13, and Rsvg2) [20,[24][25][26][27][28], and chromosome 14 (Rsv3, RSC4, and rySC13) [20,29]. Among the above five resistance loci, for which gene cloning and functional analysis have been completed, Glyma.14g204700 on Rsv3 [30], Rsc4-3 on Rsc4 [31,32], GmCAL on Rsc8 [33], GmST1 on Rsvg2 [28], and a recombinant gene on Rsc3k are involved in soybean resistance to SMV [17].…”