Localization , Accumulation , and in Rye ( Secale cereale ) Seed AntifungalActivity of Chitinases

In order to understand a physiologi¢ al role of chitinases in rye, the localization and accumulatien of rye seed chitinase-a and -c (RSC-a and -c) in the seeds were studied by imm"nochemical methods. An antiserum specific to the chitin-binding domain (CB-domain), whicb is an N-terminal part of RSC-a, and an antiserum specific to the catalytic region of RSC-a and RSC-c were used. An immunoblot analysis detected both RSC-a and RSC-c in the endosperm of the rye seed. Immunohistochemical staining indicated that RSC-a was localized in only the aleurone cells, whereas RSC-c existed at least in the starchy elldosperm and was also likely to exist in the aleuTone ce]Js. It was found by ELISA and an immunoblot ana]ysis that RSC-a and -c accumu]ated in the seed during the later stage of deyelopment. Both chitinases and the Cat-domain exhibited antifungal activity toward 7)"ichoderma species, while tlte CBdomain did not. Obseryation of the inhibition of hyphal growth of the 7L species suggests that the two chitinases acted in different ways.