Determination of Vegetative Compatibility Groups (VCGs) in Botrytis cinerea populations using Sulfate non utilizing mutant (sul)

In this research population structure of Botrytis cinerea (tel: Botryotinia fuckeliana) determined by vegetative compatibility groups (VCGs) using sulfate non utilizing mutants (sul). For this purpose 26 isolates of B. cinerea were collected from different hosts in Varamin county greenhouses. All isolates identified and purified by single spore method and cultured on BSM medium. In order to determine the vegetative compatibility groups, all isolates were cultured on Vogel's basal medium amended with sodium seleanate (1-3 gr/lit). Selenate is a toxic substance for fungi and it is an analogue for sulfate in fungal metabolic pathway. Selenate-resistant mutants were isolated from all strains as spontaneous, fast- growing sectors arising from restricted colonies on medium amended with sodium selenate. Sectors were sulphate non-utilizing (sul) mutants if grew as thin expansive colonies with little or no aerial mycelium on MM (minimal media), but similarly to the wild-type on L-methionine- amended MM medium. MM amended with potassium chromate also used for partial phenotyping of sul mutants. Mutants that grew on MM amended with potassium chromate were chromate-resistant. Also mutants with inability for growing on this medium were indicated as chromat sensitive. In order to evaluation of vegetative compatibility groups (VCGs), chromate resistance and chromate sensitive mutants were paired in all possible combinations. All plates were monitored for formation of dense aerial mycelia (prototrophic growth pattern) at the contact zone of each two isolates up to 30 days. Isolates were assigned in the same vegetative compatibility group if represented prototrophic growth pattern along their contact zone. Among 26 isolates of B. cinerea, 15 VCGs were determined. No correlations were observed between VCGs with hosts and geographic origins of isolates.