Engineering sheath blight resistance in elite indica rice cultivars using genes encoding defense proteins

Genetically transformed lines of the elite indica rice cultivars, ADT38, ASD16, IR50 and Pusa Basmati1, constitutively over-expressing rice tlp encoding a thaumatin-like protein, have been evolved for management of rice sheath blight disease. The incorporation of tlp transgene in the genomes of T₀ lines was ascertained by polymerase chain reaction and confirmed by Southern hybridization analyses. Expression of tlp in the putative transformants was confirmed by western blotting analysis. Stable inheritance of the transgene expression was studied up to T₂ generation by western blotting analysis. The putative transformants and their progenies expressing tlp showed enhanced resistance against the sheath blight pathogen, Rhizoctonia solani, when compared to the non-transformed plants. The use of rice chi11, encoding a chitinase, as a co-transgene along with tlp produced a tlp-chi11 co-transformant that showed enhanced resistance against R. solani than the ones that express tlp or chi11 transgene alone. In addition to sheath blight resistance, the tlp or chi11 transgenic lines displayed significant levels of protection against the rice sheath rot pathogen, Sarocladium oryzae.