Antilipase antibodies prevent infection of tomato leaves by Botrytis cinerea

The role of an inducible lipase (EC 3.1.1.3) during the early stages of host infection by Botrytis cinerea was studied. During growth in a liquid medium with apple cutin as the sole carbon source, B. cinerea produced a cutinase (18 kDa) and a lipase (60 kDa). The cutinolytic activity of the purified lipase was assayed. Using [H-3]cutin as substrate, the lipase showed strong cutinolytic activity at low concentrations of protein. Polyclonal antibodies raised against the lipase were purified and their immunological specificity demonstrated by immunoblotting. Lipase activity was inhibited in vitro by antilipase antibodies, and their addition with spore suspensions of B. cinerea to tomato leaves suppressed lesion formation. Although B. cinerea conidia germinated on the leaves in the presence of the antilipase antibodies, the germ tubes did not penetrate the cuticle. No immunological cross-reactivity was detected between the antilipase antibodies and any other cutinases produced by B. cinerea. These results suggest that lipase activity is required for the early stages of host infection. (C) 1998 Academic Press Limited.