Abstract

Trichoderma species are environmentally vital due to their plant growth-promoting effects, including nutrient supply enhancement, plant pathogen suppression, and plant defense promotion. Biogenic volatile organic compounds (VOCs) emitted by Trichoderma spp. have recently gained recognition for their potential role in biological control and plant growth promotion. This study evaluated the performance of Trichoderma-VOCs in plant growth promotion and suppression of plant pathogens. Ten rhizosphere Trichoderma strains with dual antagonistic effects and distinct morphological features were identified. These strains exhibited varying capacities in plant growth-promoting traits. Six plant pathogenic fungi were exposed to VOCs emitted by Trichoderma strains, revealing significant antifungal activity. Specifically, T. atroviride-VOCs and T. asperellum-VOCs completely inhibited C. destructans and A. panax. Exposure to Trichoderma-VOCs increased Raphanus sativus plant biomass by 39.8-210% and suppressed phytopathogens by 16.7-100%. VOC emission profiles of T. harzianum were analyzed using GC-MS. The results showed that Trichoderma-VOCs exhibited significant (P < 0.05) antifungal properties against all tested pathogenic fungi. Specifically, T. atroviride-VOCs decisively inhibited Alternaria panax, Botrytis cinerea, Cylindrocarpon destructans, and Sclerotinia nivalis. The presence of Trichoderma-VOCs emitted by different strains enhanced seed germination and growth. Analysis of VOC emission profiles revealed varying levels of compounds, including cyclopentasiloxane, decamethyl, cyclotetrasiloxane, and octamethyl, in T. harzianum KNU1 strain. The results highlight the potential of VOCs as a biocontrol resource against deleterious rhizosphere microorganisms and underscore the importance of Trichoderma-VOCs emissions in regulating plant growth and development. This study explored the role of volatile compounds produced by Trichoderma strains in promoting plant growth and their potential application in biological control.

Keywords: volatile organic compounds, plant growth-promotion, fungi, environment, agriculture.