Complete DNA–A and DNA–B Nucleotide Sequences of Tomato leaf curl New Delhi virus–[Thailand: Kanchanaburi:Cucumber:2012] (ToLCNDV–[TH:KR:Cu:12]) Associated with Curling Leaf of Cucumber in Kanchanaburi Province

Abstract

Analysis of genome structure of begomovirus infecting cucumber showing curling leaf without yellow symptom from Kanchanaburi province was studied in this research. The causal pathogen has not been identified previously. Total DNA extraction was carried out and the begomovirus genome was amplified by rolling circle amplification (RCA), then cut with restriction enzymes; BamHI for DNA–A and KpnI for DNA–B. DNA sequencing demonstrated that DNA–A contained 2,738 bp in length which consisted of 8 open reading frames (ORFs) including AV1, AV2, AV3, AC1, AC2, AC3, AC4 and AC5 while DNA–B contained 2,690 bp which consisted of 2 ORFs including BC1 and BV1. Comparison of the DNA–A and DNA–B sequences in this study to those belonged to begomoviruses from GenBank database reveals a close genetic relationship to the begomovirus causing tomato leaf curl in India at 98 and 94%, respectively and a close relationship to ToLCNDV–[TH:Cuc:06] DNA–A (accession no. AB330079) and DNA–B (accession no. AB330080) isolated from cucumber in the previous report at 97.26% and 92.34%. The begomovirus in this study was designated Tomato leaf curl New Delhi virus – Thailand:Kanchanaburi:Cucumber:2012] (ToLCNDV–[TH:KR:Cu:12]). Analysis of the genetic relationship among begomoviruses reported from 1999–2012 reveals that there are two species infecting cucurbits including ToLCNDV and Squash leaf curl China virus (SLCCNV). These viruses do not infect other plants in Solanaceae and Leguminosae except ToLCNDV that was reported to infect Sauropus androgynous.