Transformation Of Maize With Chitinase And β-1,3-Glucanase Gene For Resistance To Sheath Blight

Maize is the main gain crop and important industrial raw material in China, and it plays an important role in the national economy. Sheath blight is one of the most destructive diseases of the maize, and becomes one of the main factors limiting high production and high quality of corn. Chitinase and β-1,3-glucanase gene are two of broad spectrum fungal disease resistant genes, and there is a synergetic effect against fungal diseases between the two genes. The two genes were widely employed in plant genetic engineering for cultivating new cultivars of resistance to plant diseases and insect pests. At present many research results have been achieved.In this research, total RNA was extracted from phaseolus vulgaris and tobacco. The, phaseolus vulgaris chitinase gene and tobacco β-1,3-glucanase gene was acquired with Total RNA of phaseolus vulgaris and tobacco as template by RT-PCR. And on this basis, we constructed a fusion gene and a bivalent gene plant expression vectors which both contain chitinase and β-1,3-glucanase gene. Then, the fusion gene and bivalent gene vectors were introduced into immature embryo and embryonic callus induced by immature embryo of maize inbred lines A188and Z31via Agrobacterium tumefaciens-mediated method. Resistant calli were acquired after selecting on selection medium containing bialaphos. After that, the resistant calli were successively transferred to differentiation and regeneration media, and the regenerated plantlets were obtained. We acquired transgenic plants with high resistantance to sheath blight.The main results were summarized as follows:1. Construction of a fusion gene and a bivalent gene plant expression vector which both include chitinase and β-1,3-glucanase gene.2. Of all the45regenerated plantlets, there were33、25、27positive transgenic individuals identified by PCR assay for bar gene, chitinase gene, β-1,3glucanase gene, respectively. Of all the transgenic plantlets, there were20individuals which the three foreign genes had been integrated into the plant genome synchronously.3. The resistance of the transgenic plants to Rhizoctonia solani was tested using segment leaf in vitro inoculation. The results showed that the resistance to R. solani of most transgenic plants were higher than that of the control, untransformed plants, and some of them exhibited high resistantance to R. solani.4. At present, the seeds of To generation transgenic plants have been acquired and planted, and the work of T1generation transgenic plants herbicide selection is being carried out.