Soybean Cytochrome b5 Is a Restriction Factor for Soybean Mosaic Virus

Abstract

Soybean mosaic virus (SMV) is one of the most destructive viral diseases in soybeans (Glycine max). In this study, an interaction between the SMV P3 protein and cytochrome b5 was detected by yeast two-hybrid assay, and bimolecular fluorescence complementation assay showed that the interaction took place at the cell periphery. Further, the interaction was confirmed by co-immunoprecipitation analysis. Quantitative real-time polymerase chain reaction analysis revealed that GmCYB5 gene was differentially expressed in resistant and susceptible soybean plants after inoculation with SMV-SC15 strain. To test the involvement of this gene in SMV resistance, the GmCYB5 was silenced using a bean pod mottle virus (BPMV)-based vector construct. Results showed that GmCYB5-1 was 83% and 99% downregulated in susceptible (NN1138-2) and resistant (RN-9) cultivars, respectively, compared to the empty vector-treated plants. Silencing of GmCYB5 gene promotes SMV replication in soybean plants. Our results suggest that during SMV infection, the host CYB5 protein targets P3 protein to inhibit its proliferation. Taken together, these results suggest that CYB5 is an important factor in SMV infection and replication in soybeans, which could help soybean breeders develop SMV resistant soybean cultivars.

Soybean 40S Ribosomal Protein S8 (GmRPS8) Interacts with 6K1 Protein and Contributes to Soybean Susceptibility to Soybean Mosaic Virus

“…After SMV infection, SMV virions would robustly replicate and accumulate in soybean susceptible cultivars, while a small amount of SMV could be detected in the inoculated leaves of soybean resistant cultivars at the early stage of infection. Although the resistant cultivar showed extreme resistance to viruses, a slower host response allows a certain degree of virus replication and movement before conferring virus arrest [53,54]. After SMV infection, the expression of GmRPS8 was induced at the early stage of infection in the resistant Kefeng No.1 plants, while significantly upregulated in the susceptible Nannong 1138-2 plants (Figure 1), indicating that the expression of GmRPS8 was related to SMV replication.…”

Decades of Genetic Research on Soybean mosaic virus Resistance in Soybean

“…Results indicated that a single dominant gene, designated as Rsc15, conferred the SMV resistance, and it was located between Sat_213 and Sat_286 with distances of 8.0 and 6.6 cM, respectively. The candidate gene Glyma.18g154900 in RN-9 encodes the cytochrome protein GmCYB5 targeting the P3 protein of SMV to inhibit its proliferation (Luan et al, 2019) [183]. This novel resistance gene has never been found in germplasm infected by American SMV strains.…”

Overexpression of a Cinnamyl Alcohol Dehydrogenase-Coding Gene, GsCAD1, from Wild Soybean Enhances Resistance to Soybean Mosaic Virus

“…The Rsv4 locus can resist all the SMV strains at the seedling stage but often produces systemic symptoms in mature plants [ 14 ]. To date, several anti-SMV genes have been cloned, including GmPEX14 [ 15 ], GmAKT2 [ 16 ], GmPP2C3a [ 17 ], GmCnx1 [ 18 ], GmeEF1a [ 19 ], GmSN1 [ 20 ], GmKR3 [ 21 ], GmCYB5 [ 22 ], GmF3H1, GmF3H2 and GmFNSII-1 [ 23 ], GmST1 [ 24 ], Rsc4-3 [ 25 ], GmPAP2.1 [ 26 ] and GmCAL [ 27 ]. The functional mechanisms of these anti-SMV genes are mainly through regulating immune responses via increasing the contents of phytohormones (ABA or SA) or secondary metabolites (e.g., isoflavone) or R genes’ recognition of viral-encoded protein to interfere with the replication or movement of SMV in the soybean host cells.…”