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Molecular characterization of viruses in country beans (Lablab purpureus) in Bangladesh

Mohammad Rahman: Washington State University

<div>Country bean (<em>Lablab purpureus </em>L., family<em> Fabaceae</em>) is a widely cultivated legume vegetable for human consumption as a source of protein, carbohydrate, and other essential nutrients in South Asian countries. Viral diseases are one of the major constraints limiting the production of country beans in Bangladesh. During a survey of farmers’ fields in Gazipur and Comilla regions, leaves showing bright yellow mosaic symptoms were analyzed to profile viruses present in symptomatic plants. Total RNA from symptomatic leaves were subjected to Next-Generation Sequencing (NGS) using Illumina HiSeq 2000 platform. The quality filtered 125-basepair paired-end reads were assembled <em>de novo</em> into contigs using the CLC Genomics workbench 8.0 software and annotated against the viral Ref Seq database in GenBank by BLASTN program to identify viral sequences present in symptomatic samples. The results indicated the presence of sequences highly similar to <em>Bean common mosaic necrosis virus</em> (BCMNV) in symptomatic samples collected from two distinct geographic regions in Bangladesh. In pair wise comparisons, the coat protein (CP) sequences showed 100% identity between the two BCMNV isolates and showed 93-94% identity at the amino acid level with CP sequences of BCMNV isolates reported from the US and East Timor. Phylogenetic analysis of CP sequences showed that BCMNV isolates from Bangladesh formed a separate clade distinct from virus isolates characterized from the US and East Timor.</div>