Over-expression of the cloned rice thaumatin-like protein (PR-5) gene in transgenic rice plants enhances environmental friendly resistance to Rhizoctonia solani causing sheath blight disease

A 1.1-kb DNA fragment containing the coding region of a thaumatin-like prot ein (TLP-D34), a member of the PR-5 group, was cloned into the rice transfo rmation vector pGL2, under the control of the CaMV 35S promoter. The Indica rice cultivars, 'Chinsurah Bore III, 'IR72', and 'IR51500' were transforme d with the tip gene construct by PEG-mediated direct gene transfer to proto plasts and by biolistic transformation using immature embryos. The presence of the chimeric gene in T-0, T-1, and T-2 transgenic plants was detected b y Southern blot analysis. The presence of the expected 23-kDa TLP in transg enic plants was confirmed by Western blot analysis and by staining with Coo massie Brilliant Blue. Bioassays of transgenic plants challenged with the s heath blight pathogen, Rhizoctonia solani. indicated that over-expression o f TLP resulted in enhanced resistance compared to control plants.