Abstract
Protein synthesis involved in halo formation on cellulose membranes by appressoria in Colletotrichum lagenarium was investigated and role of halo formation in the penetration into cellulose membranes was clarified. The prosperity and decay of a polypeptide with molecular weight of 95K daltons (P-95), which was synthesized only when appressoria were formed, correlated with those of appearance of haloes on the cellulose membranes and cellulose digestion activity. This fact indicates that the P-95 is closely associated with cellulase, which presumably causes halo formation around the penetration sites. Appressoria formed in the presence of cycloheximide did not form haloes and penetration hyphae, but the penetration peg was observed at the site of contact of the appressorium with membranes. After removal of cycloheximide, these appressoria could elongate penetration hyphae into cellulose membranes in the presence of nutrient. Moreover, halo formation was suppressed when mature appressoria were incubated in the presence of nutrient, whereas the elongation of penetration hyphae was not affeted. These findings suggest that chemical dissolution of cellulose membranes, which causes halo formation, is dependent upon de novo protein synthesis during morphogenesis of appressoria and plays a significant role in supplying nutrient necessary for the formation of penetration hyphae.
