A high throughput functional expression assay system for a defence gene conferring transgenic resistance on rice against the sheath blight pathogen, Rhizoctonia solani

Should fruits of transgenic research on engineering resistance against crop diseases reach needy farmers, such resistance needs to be characterised thoroughly. Assessment of transgenic resistance conferred by over-expression of defence genes under field conditions or in greenhouse is a time-consuming process. It becomes often necessary, though laborious, to screen a huge population of putative transgenic lines for their resistance against a target disease. Most standard evaluation systems (SES) available for individual plant–pathogen interactions are applicable only to field conditions, and there has been a constant need for evolving a rapid laboratory method for assessment of efficacy of defence genes deployed against plant diseases. In this paper, we describe a high throughput, yet simple method for functional assessment of a rice chitinase gene chi11 known to confer resistance against Rhizoctonia solani, the rice sheath blight (ShB) pathogen. Accuracy of this method as compared with a SES already available for assessing field performance of test-varieties against ShB is discussed.