A NOVEL CHITINASE IN RICE (ORYZA-SATIVA L.) DETECTED FROM HUSK PROTEINS AND ITS GENE LOCUS

A unique protein which was induced in husk of rice strongly under high temperature (in greenhouse) and weakly under low temperature (out-of- doors) was found in a survey with two-dimensional electrophoresis, The N-terminal 16-amino-acid sequence of this rice husk protein (RHP) sho wed a significant homology with chitinases in other plant species and a complete identity with a peptide deduced from a partial sequence of registered cDNA clone SS2594 in the library of the Rice Genome Researc h Program, Japan, Thus, the deduced amino-acid sequence for SS2594 was identified as a kind of chitinases. The aminoacid sequence for SS2594 has a unique structure among other chitinases reported for rice, It i s concluded that RHP is translated from the gene for SS2594 and a prod uct of a new locus, Chi-4 (S12594) in rice, On the basis of RFLP linka ge analysis, the gene Chi-4 was located on chromosome 4.