Characterization of Bc-hch, the Botrytis cinerea homolog of the Neurospora crassahet-c vegetative incompatibility locus, and its use as a population marker

The Botrytis cinerea homolog (Bc-hch) of Nc-het-c and Pa-hch (vegetative incompatibility loci of Neurospora crassa and Podospora anserina respectively) was cloned and sequenced. The gene structure of Bc-hch is very close to those of Nc-het-c and Pa-hch. A PCR-RFLP approach on a 1171 bp fragment was used to screen polymorphism at this locus among 117 natural isolates of B. cinerea. Restriction patterns by the restriction enzyme HhaI fell into two allelic types. Moreover, haplotypes at the Bc-hch strictly corresponded to the resistance phenotypes to fenhexamid, a novel Botryticide. The use of Bc-hch as a population marker thus reveals a new structuring of B. cinerea natural populations into two groups (I and II). This result was confirmed by genic differentiation tests performed with five other markers on a sample of 132 B. cinerea isolates from the French region of Champagne.