Complex nature of infection associated with yellow vein mosaic disease in Bhendi (Abelmoschus esculentus)

Abstract

Abelmoschus esculentus (Bhendi) is a traditional vege-table crop widely cultivated and consumed commonly in India. Yellow vein mosaic disease (YVMD) caused by Bhendi yellow vein mosaic virus (BYVMV) is a major constraint for Bhendi cultivation in India. To study the nature of infection in the field, we collected leaves which showed typical YVMD in Madurai (9 plants) and carried out rolling circle amplification (RCA) for plant #6. Intriguingly, the digestion of RCA product did not yield expected fragments. This sug-gests that there may be new viruses due to recombina-tion or mutation or mixed infection. However, on digesting the RCA product of plant #1 with SacI, monomers of 2.7 and 1.3 kb were released and each was cloned into the pOK12 vector. Sequenced RCA digested products showed mixed infection by BYVMV DNA A, Okra enation leaf curl virus (OELCuV) DNA A, beta, alphasatellite with the nanovirus origin of replication. Consequently, mixed infection was also confirmed by Southern hybridization and qPCR in all the analysed plant samples. In the mixed infection of BYVMV and OELCuV, we examined high level of OELCuV DNA A accumulation.