Vegetos

Abstract

Molecular screening detected the presence of Tomato yellow leaf curl virus (TYLCV) in tomato cultivars grown at Buyeo tomato experiment station (BTES) and in tomato samples collected from two farmer green houses (FGHs). A number of cultivars viz. BT07203, BT08205, Summer King, Madison, and Rapito exhibited tomato yellow leaf curl symptoms with a variable disease incidence (1.37 to 66.86%). Maximum disease incidence 66.86% was found in Rapito cultivar while the least incidence of 1.37% was found in the Madison cultivar. Doterong TY Winner, Minichal and Blackiss cultivars and root stock cultivars (Ganmaune, BT06302, BT07302 and BT10301-2) did not show any visible symptoms of TYLCV. Both FGH samples (cherry tomatoes) showed very mild symptoms. In a whitefly transmission analysis, TYLCV inoculated tomato plants showed leaf curl symptoms similar to naturally infected plants three weeks post-inoculation. None of the other test plant species viz. chilli, potato cantaloupe, cucumber, and sweet potato showed any visible symptoms. PCR analysis of these test plants with a CP gene degenerate primers resulted in positive amplification (∼775 bp) in tomato, chilli, potato, cantaloupe, and cucumber but no such amplicon was resulted with sweet potato sample. Some apparently asymptomatic samples viz. Doterong TY winner Minichal and root stock cultivars Ganmaune, BT6302 and BT7302 were also found positive in PCR analysis. Only Blackiss and BT1031-2 cultivars (root stock) were found negative in PCR analysis. CP gene amplicons (∼775bp) obtained from 6 isolates (four BTES and one each from both FGHs were cloned and sequenced and data was deposited in GenBank. In BLASTn and phylogenetic analysis, of all six isolates (four selected from BTES and one each from both farmer green houses) shared highest (99–100%) sequence identity and close relationships with various TYLCV isolates reported from South Korea and abroad. During the study, a degenerate primer pair designed based on the CP gene sequences of TYLCV, TbLCV, and SPLCV was found to be broad spectrum begomovirus detection. In PCR analysis, primer pair amplified ToLCNDV, AEV, BYVMV, and ICMV. The primers set may be employed to detect various begomoviruses.