[Heterologous expression and functional identification of a chitinase gene from wheat]

Chitinases are functional in plant defense against pathogens and also involved in plant development as well as human disease responses. In this study a chitinase gene, Wch2, from wheat was expressed transiently in tobacco leaves and stably in transgenic Arabidopsis thaliana plants to evaluate its heterologous expression and potential application. Western blot analysis revealed that the expressed wheat chitinase was about 30 kD as was expected (Fig.1) and had hydrolytic activity towards chitin polymers (Fig.2). Integration and expression of Wch2 gene in transgenic Arabidopsis were confirmed by PCR (Fig.3) and Western blot (Fig.4) analyses. Wch2 accumulated to a high level in transgenic plants without any detectable degradation. Transgenic plants expressing Wch2 displayed a much higher resistance to Fusarium oxysporum f. sp. matthiolae, a fungus infectious to Arabidopsis thaliana than the plants containing green fluorescence protein (GFP) (Fig.5). These results indicated that Wch2 was suitable for heterologous expression in different organisms and could be used for enhancement of plant resistance in genetic engineering. The Arabidopsis-Fusarium interaction may be one of the ideal plant-fungus interaction systems for the evaluation of antifungal proteins in planta.