Molecular characterization and race identification of f. sp. infecting tomato in India.

Fourteen isolates of were isolated from wilt affected tomato samples collected from 10 different states of India. Characterization of the fungal cultures based on morphology and sequencing of ITS rDNA revealed that they belonged to f.sp. (). Pathogenicity assay on two susceptible tomato cultivars showed all the 14 isolates were pathogenic and categorized in high-, moderate- and low-virulent groups. Differential host assay on Bonny Best (no resistant gene), UC82-L (harboring ), Fla.MH1 (harboring and ) and I3R-1 (harboring , and ) tomato genotypes and PCR amplification with race-specific primers indicated that all the isolates infecting tomato in India were belonging to race 1. Molecular diversity analysis based on ISSR markers revealed the presence of 3 distinct groups of isolates. Abundant diversity was observed among the isolates in harboring the virulence-related genes (endo-polygalacturonase gene and tomatinases) and toxin production (fumonisin). However, presence of does not correlate with virulence and the isolates carrying tomatinase 4 () in combination with other tomatinase genes were of virulent group. Detection of fumonisin gene in six isolates of infecting tomato indicated their toxigenic nature.