Understanding the basis of systemic resistance induced by Trichoderma in castor bean (Ricinus communis.L).

Abstract

Elicitors released by Trichoderma upon colonizing the root system is known to confer induced systemic resistance (ISR) in plants through altered transcriptome and proteome of the host plants thus enabling them to fight against the diseases. Seedling blight disease, caused by Phytophthora parasitica var nicotiana, and wilt disease, caused by Fusarium oxysporum f.sp ricini (F. o. r), are among the major diseases of castor which cause yield reduction up to 80%. Efficacy of Trichoderma in inducing systemic resistance against these diseases was studied using different strains of Trichoderma. Colonization of castor roots by Trichoderma induced resistance against both the diseases. When compared with untreated seedlings seedling blight disease severity was reduced by 85.7% in Trichoderma (Th4d strain)-treated seedlings and similar results were obtained with respect to wilt disease. ISR by Trichoderma was confirmed by studying the expression pattern of a few signature genes known to be up-regulated during ISR. To further understand the differentially expressed genes during ISR, we have adopted RNA sequencing technique in a time series experiment and the results have shown global changes in the gene expression pattern. ISR is being further characterized by comparing proteome and metabolomes in Trichoderma treated and untreated castor seedlings.