Agrobacterium-mediated transformation of indica rice with chitinase gene for enhanced sheath blight resistance

Four rice indica genotypes of local importance were transformed with RC7, rice chitinase cDNA clone through Agrobacterium-mediated gene transfer method using mature seed derived calli as explants. The putative hygromycin resistant calli showed varied level of regeneration efficiency ranging from 2.0 to 7.6 %. The stable integration and expression of RC7 was confirmed through polymerase chain reaction (PCR) and Western analysis. Transformation efficiency ranged from 0.9 to 5.2 %. The expression of RC7 (35 kDa chitinase) in different tissues of transgenic plant (root, sheath and leaf) was proved through Western analysis and in terms of increased chitinase activity. The inheritance of transgene was studied through PCR and Western analysis in transgenic plants of Pusa Basmati 1. Bioassays with transgenic plants of local cultivars exhibited enhanced resistance up to 33.3 % to rice sheath blight pathogen Rhizoctonia solani under glasshouse conditions. Enhanced expression or 3- to 4-fold increased activity of chitinase in transgenic plants was correlated with sheath blight resistance.