Comprehensive Analysis of Soybean Mosaic Virus P3 Protein Interactors and Hypersensitive Response-Like Lesion-Inducing Protein Function

Hexiang Luan,Wenlin Liao,Xin Chen,Haijian Zhi,Xiaoyan Cui,Haopeng Niu

doi:10.3390/ijms20143388

Abstract

Soybean mosaic virus (SMV) is one of the most prevalent and important pathogens of soybean, which produces 11 proteins, and the third protein, P3, was suggested to be involved in virus movement and replication, as well as host infection. During the virus infection, host proteins are essential in the virus cycle. However, there is no comprehensive report on the network of host proteins that interact with P3. Fifty-one interactors were identified by using the P3 protein as the bait against the SMV SC15 strain-challenged soybean cDNA library. These proteins were classified into five groups, including transport and protein transport-related proteins, defense and disease-related proteins, photosynthesis proteins, cellular metabolic proteins, and unknown proteins. Among these proteins, the protein defined as hypersensitive response-like lesion-inducing (HRLI) appeared multiple times and showed strong affinity with P3, which indicated its important role in SMV infection. Thus, it was chosen for further investigation. Phylogenetic classification showed that paralog proteins GmHRLI-1 and GmHRLI-2 clustered together and shared 90% homologous identity. Bimolecular fluorescence complementation (BiFC) assay was carried out to confirm the interaction, and fluorescence was detected at the cell periplasmic as well as at the nucleus. Subcellular localization showed that GmHRLI was localized to the cell periplasmic, while the co-localization of GmHRLI and P3 signals was also observed in the nucleus, suggesting that GmHRLI could interact with P3 and promoted the translation of P3 to the nucleus. Moreover, the gene expression of GmHRLI was abundant in the roots, leaves, and flowers, and could be induced by SMV infection, suggesting its involvement in SMV infection. Our results together lay the foundation to explore the mechanisms of P3 in the HR process and the HRLI protein function in SMV response.

Highlights

Soybean is an important resource of oil all over the world
The soybean mosaic virus (SMV) P3 was amplified from cDNA produced from the soybean leaf tissue inoculated with the soybean SC15 strain using the primer with Sfi I endonuclease sequence (Figure 1A)
The recombinant vector was validated by restriction enzyme digestion, which showed that the P3 fragment was released from the construct after Sfi I digestion (Figure 1B), indicating that the P3 was inserted into the bait vector

Summary

Introduction

The potyvirus soybean mosaic virus (SMV) is one of the most widely distributed viral pathogens and an important disease that affects soybean [Glycine max (L.)] production [1]. SMV infection has been reported to cause 15–30% loss of yield [2]. SMV infection results in leaf wrinkling, mosaic symptoms, and necrosis in soybean, and reduces the chlorophyll content in the chloroplast. Based on the phenotypic reaction on a set of differential soybean cultivars, SMV isolates have been classified into seven strains in North America (G1–G7) [5,6], and 21 strains in China (SC1-SC21) [7,8]. Genetic mapping has identified three resistance genes (Rsv, Rsv, Rsv4) that provide resistance against North American strains and a series of genes (Rsc, Rsc, Rsc, Rsc14) that provide resistance against strains from China [9,10,11,12]

Methods

Results

Conclusion