First report of bean common mosaic virus (BCMV) infection of African yam bean (Sphenostylis stenocarpa) in Nigeria

Abstract African yam bean (Sphenostylis stenocarpa) is one of the underutilized crops that has the potential to help sustain food security in this era. In October 2021, more than 90% African Yam Bean (AYB) plants in the grain legumes field of the Institute of Agricultural Research and Training (IAR&T), Nigeria showed typical virus symptoms of mosaic and necrosis. To identify the virus leaf sasmples were subjected to ELISA and PCR tests. The symptomatic leaves were positive for anti-BCMV and anti-potyvirus antiseraand PCR to amplify a partial coat protein gene of BCMV yeilded a product of 469bp. The generated sequence was deposited in the GenBank and assigned NCBI GenBank Acc. No OL763314. The nucleotide sequence of the coat protein gene had 99% identitywith BCMV isolate TN2 (KY044818). The identities of the nucleotide and amino acid sequence of the CP gene of the isolated virus relative to those of other potyviruses were 31.3–99.1% and 43.8–66.8%, respectively. Phylogenetic analyses of the partial CP-nucleotide sequences grouped the Isolate from this study (BCMV-IART-AYB) and BCMV-TN2 in the same cluster with other BCMV strains of the peanut stripe (PSt) and the blackeye cowpea (BlC) strains. In this study, we charaterize Bean commom mosaic virus (BCMV) infecting AYB in Nigeria and show that it has low nucleotide and amino acid identity with an Isolate of cowpea-infecting BCMV in Nigeria.