Enhanced Resistance To Rice Bacterial Blight Achieved By Vascular Specific Expression Of T4 Lysozyme

Bacterial blight caused by Xanthomonas oryzae pv. oryzae(Xoo) is one of the most serious rice diseases in the world. The pathogen normally enters the host through wounds or natural openings such as the water pores, multiplies and moves throughout the plant via vascular tissues. In this thesis a chimeric gene, p1300gdcsP:lys, was constructed by using a vascular specific promoter, gdcsP isolated from C3-C4 intermediate plant Flaveria anomala and T4 lysozyme gene (its product is able to cleave the peptidoglycan of bacterial cell walls and results). The chimeric gene was inserted into the binary vector pCambia1300 and introduced into the rice (Oryza saliva L.) cv. TP309 and FY516 by particle bombardment and Agrobacteriwn-mediated gene transfer. Sixty-five independent lines of transgenic rice plants (forty-five for TP309, twenty for FY516) were regenerated, and forty-four of these lines carried T4 lysozyme gene as shown by PCR and Southern analysis. A bacterial blight inoculation test revealed some plants carried the T4 lysozyme geneshowed enhanced resistance to Xoo CI (HLJ-72), CII (HB17) ,CIII (NX-42) at various levels, and two of them showed very high resistance to Xoo. Since gdcsP promoter showed no expression in the endosperm and late stage of mature leaves, the gdcsP:lys chimeric gene construct was extremely useful in applied use of controlling rice bacterial blight and free of the public concerns on biosafety.