APS Homepage

Poster: Diseases of Plants: Disease Detection & Diagnosis


Complete nucleotide sequences of a new bipartite begomovirus from Malvastrum sp. plants with bright yellow mosaic symptoms in South Texas
O. ALABI (1), C. Villegas (2), L. Gregg (3) (1) Dept. of Plant Pathology & Microbiology, Texas A&M University AgriLife Research & Extension Center, U.S.A.; (2) South Texas College, U.S.A.; (3) Texas A&M AgriLife Research and Extension Center, U.S.A.

Two isolates of a new bipartite Begomovirus, tentatively named as Malvastrum bright yellow mosaic virus (MaBYMV), were molecularly characterized from naturally-infected Malvastrum sp. plants showing bright yellow mosaic disease symptoms in South Texas. The host plant genus identity was determined by DNA barcoding of the non-coding trnH-psbA intergenic spacer region and the matK plastid gene. Restriction enzyme-digested rolling cycle amplification products from symptomatic plants were used as template in PCR to amplify complete virus genome segments with pairs of newly-designed abutting primers. The obtained ~2.7 Kb fragments were cloned and sequenced. Six complete DNA-A and five DNA-B genome sequences of MaBYMV obtained from the two isolates ranged in length from 2,608-2,609 nucleotides (nt) and 2,578-2,605 nt, respectively. Both genome segments share a 178-180 nt common region. In pairwise comparisons, complete DNA-A and DNA-B of MaBYMV were most identical (87-88% and 79-81%, respectively) and phylogenetically related to corresponding sequences of Sida mosaic Sinaloa virus-[MX-Gua-06]. Further analysis showed that MaBYMV is a putative recombinant virus, thus supporting the notion that malvaceous hosts may be influencing the evolution of several begomoviruses. The design of new diagnostic primers enabled the detection of MaBYMV in cohorts of Bemisia tabaci collected from symptomatic Malvastrum sp. plants, thus implicating whiteflies as potential vector of the virus.