First report of Dicliptera yellow mottle virus (DiYMoV) infecting Dicliptera vahliana in Cuba

Recently, common weed plants such as Dicliptera sexagularis have been suggested as natural host reservoirs for geminiviruses, from which crop plants might be infected (Lotrakul et al., 2000). Leaves showing typical yellow mottle symptoms were collected from Dicliptera vahliana plants in the province of Havana, Cuba during 2000-2001. Healthy D. vahliana were inoculated using graft procedures and mechanically using sap and total DNA extracts from infected leaves collected in this region. Dicliptera yellow mottle symptoms were more efficiently reproduced using a graft procedure (15 infected/20 inoculated plants) than following mechanical inoculation (8 infected/20 inoculated plants). Symptoms reproduced by both inoculation procedures were similar to those showed by the source plants. The presence of a begomovirus was evident by Southern blotting with strong hybridization signals obtained using the DNA-A of Bean golden yellow mosaic virus-CU as a probe, under high stringency conditions. Total DNA was further analyzed by PCR using two degenerate primer sets: PAL1v 1978- PAR1c 715 and PAL1c1960- PAR1v 722 (Rojas et al., 1993). Fragments of approximately 1.4 kb and 1.2 kb were amplified and cloned. Sequences from three clones of each amplicon were obtained and the component A sequence was assembled. Fragments were compared with those for other begomoviruses using CLUSTAL W. From the deduced amino acid sequences of the coat protein (753 nt) and rep genes (1017 nt) and the complete DNA-A nucleotide squence, the highest percentages of identity were with DiYMoV (GenBank Accession No. AF139168) at 98%, 84.9% and 87.6% respectively. Common region (CR) analysis revealed a high percentage identity with BGMV-BZ (M88686) at 72.1%, TGMV-YV (K02029) at 69.3 % and DiYMoV at 66.7%. The iterative sequence GGTAGA (GGTAV) was identified in the CR of DiYMoV Cuban isolate, which has also been found in other begomoviruses e.g. ICMV, TYLCSV-Sic and TGMV-YV (Arguello-Astorga & Ruiz-Medrano, 2001). Thus, the virus isolated from Dicliptera vahliana plants affected by yellow mottle in the province of Havana, is a strain of DiYMoV, with the suggested acronym DiYMoV-CU.