Nucleotide sequence of a Brassica napus endochitinase gene

Endochitinase (EC 3.2.1.14, chitinase), which catalyzes the hydrolysis of the beta -1,4-linkages of the N-acetyl-D-glucosamine of the fungal cell wall polymer chitin, is involved in inducible defenses of plants against potential pathogens. Here we report the nucleotide and deduced amino acid sequences of a genomic clone (BnCh25) encoding a class I endochitinase from Brassica napus cv Westar. The nucleotide sequence of the coding region of this B. napus chitinase is 86.5% homologous with an endochitinase from Arabidopsis thaliana, 70.0% with one from Nicotiana tabacum, and 69.1% with one from Phaseolus vulgaris. Furthermore, the B. napus gene presents the same expression pattern as an organ-specific basic chitinase gene from A. thaliana that was shown to be expressed at high constitutive level in roots, with lower levels in leaves and flowering shoots from healthy plants.