Abstract: The chitinase gene was cloned and its function was further analyzed by genetic transformation, aiming at exploring the role of chitinase gene in resisting fungal diseases in peanut.The DNA (1 779 bp) and cDNA (795 bp) of peanut chitinase gene were obtained successfully by PCR and RT-PCR amplification, with the genomic DNA and cDNA of peanut variety Huayu 23 as templates respectively.The sequence alignment result between DNA and cDNA showed that peanut chitinase gene contained three exons and two introns, conforming to "GT……AG" rule in intron splicing. The cDNA coding sequence contained 795 bp, coded for a 265-amino acid protein, and was named by Ah-Chi, which was registered in NCBI (GenBank accession No. HQ439775). As determined by Blast analysis, the Ah-Chi protein had homology with proteins from Oryza sativa (83%), Zea mays (83%), Medicago sativa (72%), Glycine max (58%) and Arabidopsis thaliana (49%). The over-expression vector pCAMBIA1301-Ah-Chi was constructed successfully by substituting Gus of pCAMBIA1301 for Ah-Chi, and then was transformed into peanut embryonic leaflets explants by Agrobacterium EHA105 mediated transformation. The regenerated plants were then obtained by grafting and transplanting those regenerated somatic embryo seedlings.These transgenic positive plants were further screened and verified by PCR amplification, and the increased expression level of Ah-Chi was confirmedin transgenic plants by RT-PCR amplification. Cercosporidium personatum was inoculated to the detached leaves of transgenic and non-transgenic plants. Seven days later, it was found that the non-transgenic plants showed more serious leaves' browning and necrosis than transgenic plants, which indicated that the disease resistance of transgenic plants were enhanced.

Key words: Peanut, Chitinase gene, Genetic transformation, Disease resistance, Cercosporidium personatum

CLC Number: 

• Q785