Occurrence of a lipase in spores of Alternaria brassicicola with a crucial role in the infection of cauliflower leaves.
Alternaria brassicicola is a pathogen that penetrates directly through the host cuticle thanks to several serine esterases, according to our findings. Among these, an 80-kDa lipase (E.C 3.1.1. 3) was detected by SDS-PAGE and immunoblotting in the water washings of ungerminated spores. The purified lipase cross-reacted with Botrytis cinerea anti-lipase antibodies, which were reported to inhibit the in vitro lipase activity. Anti-lipase antibodies were added to a conidial suspension of A. brassicicola prior to inoculation. As a result, blackspot lesions were reduced by 90% on intact cauliflower leaves, but not on leaves from which surface wax had been removed. Spore surface-bound lipase is thought to interact closely with epicuticular leaf waxes for adhesion and/or penetration of the fungal propagules during the early stages of host-parasite interactions.
Berto
P
P
Université des Sciences et Technologies de Lille, Laboratoire de Cryptogamie-Phytopathologie, F-59655, Villeneuve d' Ascq, France.
Comménil
P
P
Belingheri
L
L
Dehorter
B
B
D000528:Alternaria / Q000201:enzymology* / Q000472:pathogenicity / Q000502:physiology; D000908:Antibodies, Fungal / Q000276:immunology; D001937:Brassica / Q000382:microbiology*; D004591:Electrophoresis, Polyacrylamide Gel; D004950:Esterases / Q000276:immunology / Q000378:metabolism; D005656:Fungal Proteins / Q000276:immunology / Q000378:metabolism; D015151:Immunoblotting; D008049:Lipase / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D013172:Spores, Fungal / Q000201:enzymology*
D000908:Antibodies, Fungal; D005656:Fungal Proteins; D004950:Esterases; D008049:Lipase