Decoding Volatile Organic Compounds' Signatures of 14 Trichoderma Isolates to Predict Antifungal Activity against Rice Pathogens through Integrated Chemical, Multivariate, and Computational Analyses.

Volatile organic compounds (VOCs) produced by Trichoderma spp. play a pivotal role in the biocontrol of phytopathogens. In this study, VOC profiles were characterized from 14 isolates representing eight Trichoderma species, and their antifungal activity was evaluated against Sclerotium oryzae and Rhizoctonia solani. The isolates CRRI-T5 (T. atroviride) and NRRI-T27 (T. reesei) were found to be the most potent isolates. VOCs of potent isolates were enriched in short-chain esters, alcohols, ketones, lactones, and monoterpenes. Orthogonal partial least-squares (OPLS) analysis showed that compounds 2-heptanone, 6-pentyl-α-pyrone (6-PP), p-dichlorobenzene, δ-dodecalactone, and 1-octanol were linked to inhibition of both pathogens. 6-PP showed the strongest antifungal effect against both S. oryzae and R. solani, with 3-methyl-1-butanol showing activity against S. oryzae. Molecular docking studies showed that these compounds could inhibit the activities of the enzymes trehalase, pectate lyase, and cytochrome P450 (CYP51). This integrated approach helped to identify antifungal VOCs of Trichoderma strains.