Identification of New Alleles for Resistance to Soybean Mosaic Virus in Soybean

Abstract

Soybean mosaic virus (SMV) is one of the most prevalent viral diseases in all major soybean [Glycine max (L.) Merr.] growing areas worldwide, causing substantial yield losses and seed quality deterioration in soybean. Seven strain groups of SMV (G1–G7) in the United States and three resistance loci (Rsv1, Rsv3, and Rsv4) have been identified in soybean. The objective of this research was to screen diverse soybean germplasm in attempt to identify new alleles for SMV resistance. A total of 253 soybean accessions collected from 26 countries were screened with six SMV strains in the greenhouse. The results showed that 157 accessions were susceptible to all six tested SMV strains, 75 accessions were resistant to some of strains, while 21 accessions were resistant to all strains tested. Among the resistant accessions, seven showed complete resistance to six strains and presumably carried Rsv1‐h, Rsv4, or combinations of Rsv1, Rsv3, and Rsv4; 14 showed resistance or early seedling stage resistance to six strains and presumably carried the Rsv4 allele; 50 accessions exhibited similar reaction patterns to known alleles: two Rsv1, 22 Rsv1‐k, 16 Rsv1‐y, one Rsv1‐t, and nine Rsv3 Twenty‐five accessions showed distinct reaction patterns and presumably carry new alleles. The resistant accessions identified in this study will be valuable germplasm resources for breeding SMV resistance.

Two Tightly Linked Genes for Soybean Mosaic Virus Resistance in Soybean

“…Among the seven U.S. strains of SMV, the G1 is the least, and G7 is the most virulent strain. The Rsv1 is the most common in SMV-resistant soybean germplasm, and most diverse multiallelic locus with 10 indentified alleles (Li et al, 2010;Shakiba et al, 2012;Zheng et al, 2005). The Rsv1 is the most common in SMV-resistant soybean germplasm, and most diverse multiallelic locus with 10 indentified alleles (Li et al, 2010;Shakiba et al, 2012;Zheng et al, 2005).…”

“…SMV-G1 is also the most prevalent and predominant in nature (Cho and Goodman, 1979). The Rsv5 (Rsv1-y) is also the most common R-gene in soybean germplasm collection (Li et al, 2010;Shakiba et al, 2012;Zheng et al, 2005); therefore, there is a possibility that the Rsv1 and Rsv5 are the earliest resistance genes that confer resistance to the less aggressive SMV strains (Table 1). The SMV-G1 strain and the Rsv1 gene must have gone through a long course of co-evolution in nature, which led to emergence of new and more aggressive strains and other resistance genes.…”

The evolution of soybean mosaic virus: An updated analysis by obtaining 18 new genomic sequences of Chinese strains/isolates

“…Among the cultivars, 12 ('Essex','Lee68','PI96983','Suweon97','Raiden','Tousan50','Kwanggyo','Marshall','Ogden','York','L29', are currently employed in the U.S.A. to distinguish strains G1-G7 (Li et al, 2010a;Shakiba et al, 2012) and eight (NN1138-2, 8101, Youbian30, Davis, Zaoshu18, Kwanggyo, Qihuang No. 1, and Kefeng No.…”

Identification of a New Allele at the Rsv3 Locus for Resistance to Soybean Mosaic Virus in PI 61944 Soybean Accession

“…The SMV causes disease symptoms characterized as stunting, reduction of seedling viability and vigor, seed-coat mottling, flower abortion, seed size reduction, and reduction of pod set and seed number (Ross, 1983;Buss et al, 1989;Hill et al, 1987;Gunduz et al, 2004). The intermediate strains expressed noticeable symptoms: G2 produced necrosis on Marshall, G3 produced necrosis on Marshall and Ogden, G4 produced necrosis in York and Davis, G5 produced mosaic symptoms in York and Davis and necrosis in Kwanggyo and Raiden, and G6 produced necrosis in Marshall and Kwanggyo (Li et al, 2010). The SMV strains were categorized into seven strain groups of virulence (G1-G7) ( Table 1): G1 was the least virulent strain, which did not infect any of the cultivars with known resistance, and G7 was the most virulent strain that infected all cultivars and caused necrosis or mosaic symptoms.…”

“…Susceptible symptoms allow ample virus replication and systemic viral movement in plants. The Rsv1 locus was identified in the soybean line PI 96986 (Rsv1) and provides resistance to the least and susceptibility to the most virulent strains, and ten resistance alleles (Rsv1, Rsv1-t, Rsv1m, have been identified at this locus (Table 1) Li et al, 2010). The virus and mosaic symptoms move and spread to new leaves as they develop further.…”