DNA Analysis Confirms Macroptilium lathyroides as Alternative Host of Bean golden yellow mosaic virus.

The leguminous weed Macroptilium lathyroides is considered a potential host of the Bean golden yellow mosaic virus (BGYMV; BGMV = Mesoamerican isolates). To determine if M. lathyroides could be a host for BGYMV, an infectivity cycle was established between this weed and Phaseolus vulgaris. Virus transmission was carried out using the whitefly, Bemisia argentifolli, as a vector. Inoculated plants of both species were examined for symptoms such as mosaic, stunting, and leaf distortion. P. vulgaris and M. lathyroides showed golden yellow mosaic symptoms during all infectivity cycle stages. Symptomatic plants of both species were tested for BGYMV using polymerase chain reaction (PCR) and nucleotide sequence analysis. Two degenerate primers sets were used for PCR to detect viral DNA: PAL1v1978/PAR1c715 and PCRc2/PBL12039. PCR analysis using primers PCRc2/PBL12039 amplified viral DNA for component B from both plant species. Nucleotide sequence analysis revealed a 93% identity between the virus isolated from M. lathyroides and the Puerto Rican isolate of BGYMV. These results confirmed that M. lathyroides could serve as an alternative host of BGYMV and that an infectivity cycle of BGYMV could possibly occur between P. vulgaris and M. lathyroides in Puerto Rico.