Enhanced resistance to Botrytis cinerea and Rhizoctonia solani in transgenic broccoli with a Trichoderma viride endochitinase gene

摘要

A endochitinase gene (Tch ) from the fungus Trichoderma viride was introduced into broccoli (Brassica oleracea var. italica) by Agrobacterium-mediated transformation. Sixty-eight putative transformants were obtained and the presence of the Tch gene was conifrmed by both PCR and Southern blot analysis. RT-PCR analysis showed an accumulation of the transcript encoding the endochitinase protein in the transgenic plants. Using real-time quantitative PCR, the expression proifling of endochitinase gene was analyzed. Primary transformants and selfed progeny were examined for expression of the endo-chitinase using a lfuorometric assay and for their resistance to the pathogenic fungi Botrytis cinerea and Rhizoctonia solani. The endochitinase activities in T0 in vitro plants, T0 mature plants and T1 mature plants were correlated with leaf lesions, and the transgenic line T618 had high endochitinse activities of 102.68, 114.53 and 120.27 nmol L–1 MU min–1 mg–1 protein in the three kinds of plants, respectively. The endochitinase activity showed a positive correlation with the resistance to the pathogens. Most transgenic T0 broccoli had increased resistance to the pathogens of B. cinerea and R. solani in leaf assays and this resistance was conifrmed to be inheritable. These ifndings suggested that expression of the Tch gene from T. viride could enhance resistance to pathogenic fungi in Brassica species.