Enhanced sheath blight resistance in transgenic rice expressing an endochitinase gene from Trichoderma virens

Abstract

The 42-kDa endochitinase (cht42) gene from the mycoparasitic fungus, Trichoderma virens, driven by CaMV 35S promoter, was introduced into rice by Agrobacterium-mediated transformation. Eight transgenic plants harboring single copies of complete T-DNA were identified by Southern blot analysis. Homozygous transgenic plants were identified for five lines in the T₁ generation by Southern blot analysis. Homozygous T₂ plants constitutively accumulated high levels of the cht42 transcript, showed 2.4- to 4.6-fold higher chitinase activity in total leaf extract and 1.6- to 1.8-fold higher chitinase activity in the extracellular fluid. Infection assays performed on the homozygous T₂ plants with Rhizoctonia solani showed up to 62% reduction in the sheath blight disease index.