CLONING，SEQUENCE ANALYSIS AND INDUCED EXPRESSION STUDIES OF A CHITINASE GENE M-CHITINASE FROM MULBERRY (MORUS L.)

A full-length cDNA sequence coding for Chitinase in mulberry, which we designated M-chitinase (GenBank accession number: HQ117891) was cloned based on mulberry expressed sequence tags (ESTs) isolated from the cDNA library. Its full open reading frame was obtained by RACE and RT-PCR. Sequence analysis showed that the M-chitinase gene is 1392 bp in length and contains a 60 bp 5’-UTR (un translated region) and a 255 bp 3’-UTR. Its open reading frame (ORF) is of 1077 bp long, encoding 358 amino acids with a predicted molecular weight of 38.52KDa and an isoelectric point of 4.466. Homology analysis revealed that M-chitinase gene in mulberry is highly conservative with other species including N. khasiana, Zea mays and Zea Diploperennis. Phylogenetic analysis based on M-chitinase gene with other 19 species revealed that mulberry shows closer relationship with Nicotiana gossei, Nicotiana tabacum, Capsicum annuum and Arabis blepharophylla. The results of semi quantitative RT-PCR analysis showed that the mRNA transcriptional level of M-chitinase in the young leaf was changed significantly under the conditions of signal transduction mechanism underlying the stress response in mulberry.