A group from College of Plant Protection, Hainan University, Haikou, Hainan, China, etc. has reported that the 13 trichoderma strains are promising biocontrol agents and could be developed as biofertilizers and biological pesticides for agricultural applications.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8714372/
The 13 Trichoderma strains that significantly promoted the seed germination were further tested for their effect on root growth of watermelon, chili, eggplant, and tomato seedlings. In greenhouse experiment, all strains showed a promotion effect on root growth of chili seedlings, and among them, HL100 strain showed maximum increase 12.17% in root length compared to control. Three strains (GZ070, HL100, and HN059) significantly promoted the root growth of watermelon seedlings. HN059 strain showed maximum increase of 18.81% in root length compared to control. Trichoderma strains GZ070, HL100, HN059, JX013, XJ087, and NX043 strains and HL119, HN059, SC012, XJ035, SC098, and SC101 were found to promote the root growth of eggplant and tomato seedlings, respectively. The highest increase in root length of eggplant (40.99%) and tomato plants (34.68%) was recorded by GZ070 and SC098 strains, respectively.
Trichoderma grows rapidly and can quickly occupy the growth space of pathogenic fungi, which is one of the important mechanisms of their antimicrobial effect.
The production of cell wall-degrading enzymes (CWDEs) and volatile antibiotics is key parameters for Trichoderma as a biocontrol agent. It was found that 13 Trichoderma strains (PI > 85%) with excellent antagonism to pathogens could secrete chitinase and β-1,3-glucanase, which were closely related to the cell wall composition of pathogens. Therefore, Trichoderma can not only compete with pathogens for space and nutrition but also degrade the cell walls of pathogens, deform, or even digest the hyphae, and inhibit the growth of pathogens.
As references, some reports suggested that root colonization by Trichoderma strains could increase levels of defense-related plant enzymes, including various peroxidases, chitinases, β-1,3-glucanases, and the lipoxygenase-hydroperoxide lyase pathway. In cucumber, root colonization by strain T-203 causes an increase in phenolic glucoside levels in leaves; their aglycones (which are phenolic glucosides with the carbohydrate moieties removed) are strongly inhibitory to a range of bacteria and fungi.