Abstract
Plant chitinases are well known as pathogenesis-related (PR) proteins because of their antifungal activity.Although higher plants have several chitinase isozymes, it would not be reasonable to assume that all chitinase isozymes function as the antifungal protein.To elucidate the physiological functions of plant chitinases, we analyzed mRNA levels of three chitinase isozymes (AtChiA,AtChiB,AtChiV) in Arabidopsis thaliana on various growth stages or under some stress conditions.Chitinase activities in roots and siliques were higher than those in other organs from setting seed.Allosamidin inhibited the chitinase activities from roots, rosettes, and shoots, indicating that these organs contained family 18 chitinase.By RT-PCR using specific primers for each chitinase isozymes, we found that AtChiB and AtChiV were expressed through the entire growth stages in all organs.On the other hands, AtchiA was not expressed in any organs under normal growth conditions, but expressed by exposure to injury, ethephon, and NaCl stresses.
