Identification of a New Genetic Clade of Cowpea Mild Mottle Virus and Characterization of Its Interaction With Soybean Mosaic Virus in Co-infected Soybean

Abstract

Cowpea mild mottle virus (CPMMV; genus Carlavirus) can be a destructive pathogen of soybean but there is little information about its distribution on soybean in China. Here, we collected soybean plants with virus-like symptoms from 11 fields widely scattered within China, and used high-throughput sequencing to determine their virome. Most samples (8/11) were co-infected by the well-studied potyvirus soybean mosaic virus (SMV) and CPMMV, and the remaining three samples were singly infected with CPMMV. The near-complete genome sequences of the 11 CPMMV isolates were determined and phylogenetic analysis showed that they constituted a new genetic clade. One recombination event was detected among the CPMMV sequences, and the isolate CPMMV_JL_CC was identified as recombinant. In mechanical inoculation assays, co-infection by CPMMV and SMV resulted in an enhancement of disease symptoms, but decreased the expression level of the genomic RNAs and CP of CPMMV, without significantly affecting SMV accumulation. The interaction between these viruses needs further investigation.

The hypervariable N-terminal of soybean mosaic virus P1 protein influences its pathogenicity and host defense responses

“…In a previous study of SMV isolates from different soybean-growing areas in China, we identified isolate SMV_JL_GZL (SMV GZL ) that causes leaf crinkling of soybean and clusters separately from other Chinese SMV isolates in phylogenetic analyses (Wei et al 2021). We now report another SMV isolate, SMV_ZJ_NB (SMV NB ), which causes severer symptoms and accumulates virions in plants to a greater extent than SMV GZL .…”

“…SMV NB and SMV GZL isolates caused different symptoms on soybean SMV_ZJ_NB (SMV NB ), an isolate of SMV newly obtained from soybean in Ningbo, China, was compared with isolate SMV_JL_GZL (SMV GZL , GenBank Access no. MW354946.1) that had been obtained from northeast China through high-throughput sequencing (HTS) in a previous study (Wei et al 2021). Both isolates were inoculated to soybean cv.…”

“…Inoculation of soybean plants was performed as previously described (Wei et al 2021). Sap from symptomatic plants was used to inoculate a susceptible soybean variety (Dongnong 51).…”

Infectivity Assays for Soybean and Cowpea Mosaic Viruses and Their Management

“…A severe mosaic pattern appeared on healthy leaves of Cowpea seedling after the inoculation. The same mechanically inoculation process for other virus has been previously reported by (Ali et al, 2020;Wei et al, 2021). During the present study, the infected samples were collected, then an ELISA test was performed for the confirmation of SMV and CMV.…”

The C-Terminal Transmembrane Domain of Cowpea Mild Mottle Virus TGBp2 Is Critical for Plasmodesmata Localization and for Its Interaction With TGBp1 and TGBp3

“…It was first reported to infect cowpea in Ghana but was then found to infect legumes and other crops across the world (Brunt and Kenten, 1973). Recent studies have shown that CPMMV is also widely distributed in China, causing severe damage to soybean yields (Wei et al, 2021). The CPMMV genome has six ORFs, which encode an RNA-dependent RNA polymerase protein (RdRp), triple gene block proteins (TGBp1, p2, and p3), coat protein (CP), and a cysteine-rich protein with nucleic acid binding activity (CRP) (Menzel et al, 2010).…”