Cystathionine γ-lyase is an essential biocontrol-positive regulator of Trichoderma gamsii strain TC788.

Some Trichoderma strains have been widely used in agriculture due to their biological control functions against plant pathogens. However, only a few intracellular biocontrol-related factors of them were explored. In this study, T. gamsii strain TC788 was discovered possessing comprehensive antagonistic capacity to the fungal phytopathogen Rhizoctonia solani causing damping-off disease of pepper, in which cystathionine γ-lyase is proved to be an essential biocontrol positive regulator as evidenced by combined analyses of transcriptome and proteome, proteins interaction network, and gene homologous recombination. Overexpression of cystathionine γ-lyase significantly up-regulated expression levels of six pathway proteins and enzyme activities of secreted proteins associated with biocontrol. It also increased contents of cysteine and hydrogen sulfide in enriched pathway of cysteine and methionine metabolism, and improved concentration of the main volatile organic compound, 6‑pentyl‑2H‑pyran‑2‑one, by 4.18 times. Pot experiments further confirmed that overexpressed strain of TC788 enhanced inhibiting ability against R. solani, promoted growth indicators, and induced systemic resistance of pepper seedlings compared with wild type strain. This work provides theoretical bases of biocontrol effects performed by strain TC788 against the phytopathogen, and explores preliminarily interaction between the strain and pepper plant.