Deciphering the biocontrol strategies of Trichoderma yunnanense TM10 against Fusarium oxysporum f. sp. cepae, the causal agent of wilt disease in shallots (Allium cepa var. aggregatum)

The fungal genus <i>Trichoderma</i> has demonstrated significant potential for agricultural applications, particularly as a plant growth promoter and biocontrol agent against various phytopathogens. This study evaluated <i>Trichoderma yunnanense</i> TM10 as a biocontrol agent against <i>Fusarium oxysporum</i> f. sp. <i>cepae</i> (Foc) in shallots through both <i>in vitro</i> and <i>in vivo</i> assays. <i>In vitro</i> assays demonstrated that <i>T. yunnanense</i> TM10 effectively inhibited the growth of Foc through several mechanisms, including mycoparasitism, antibiosis, and competition for space between TM10 and Foc. Gas chromatography-mass spectrometry analysis identified eight volatile organic compounds exhibiting antimicrobial potential, while liquid chromatography-mass spectrometry analysis revealed eighteen non-volatile organic compounds with antifungal properties against Foc. <i>In vivo</i> assays showed that TM10 reduced disease severity by approximately 53.5 % and improved plant physiological characteristics, as shown by increased chlorophyll content, carotenoids, phenolic content, and antioxidant enzyme activity. Morphological improvements were also evident, with greater root and leaf elongation, higher biomass accumulation, and a higher number of leaves compared to pathogen-infected control plants. These findings suggest that <i>T. yunnanense</i> TM10 controls Foc through multiple mechanisms while promoting plant health, making it a promising and sustainable biocontrol agent for managing <i>Fusarium</i> wilt in shallots.