Molecular characterization of common bean curly stunt virus: a novel recombinant geminivirus in China.

A new geminivirus was identified in common bean (Phaseolus vulgaris) showing severe stunt and leaf curling symptoms in Heilongjiang province of China, via sequencing and assembly of small RNAs. The genome of this geminivirus comprises 2,959 nucleotides (nt) and shares 21.77-54.97% nt sequence identity with other geminiviruses. The coat protein (CP) shares the highest amino acid (aa) sequence identity (23.5%) with that of sesame curly top virus (SeYMV; genus Turncurtovirus), whereas the C1 (Rep) shares the highest aa sequence identity (66.5%) with that of beet severe curly top virus (BSCTV; genus Curtovirus). This geminivirus neighbors the turncurtoviruses in phylogenetic trees based on the full genome sequence or the amino acid sequence of the Rep protein, but it forms a distinct clade in the phylogenetic tree based on the coat protein. Recombination analysis showed that parts of the C1 coding region of this geminivirus were recombined from a curtovirus or turncurtovirus. Based on these results, the name "common bean curly stunt virus" (CBCSV) is proposed for this virus.