Cloning and expression of the cutinase A gene of Botrytis cinerea

Cutinase of Botrytis cinerea has been suggested to play an important role in penetration of host tissues. A protein fraction with cutin hydrolyzing activity was purified from culture filtrates of B. cinerea induced for cutinase activity. An 18-kDa protein in this fraction was identified as cutinase and the corresponding gene cutA was cloned. The gene is present in a single copy in the genome of B. cinerea strain SAS56 and its predicted amino acid sequence shows significant homology (31 to 35% identity) to other fungal cutinases. RNA blot analysis showed that cutA mRNA is induced in vitro by the cutin monomer 16-hydroxyhexadecanoic acid and repressed by glucose. The expression of cutA during infection of tomato leaves is low during early phases of infection, but high when the fungus has colonized the leaf and starts to sporulate.