Comprehensive In Vitro Evaluation of the Biocontrol Potential of Trichoderma virens Against Selected Phytopathogenic Fungi: Integration of Interaction Dynamics and Best-Fit Mathematical Modeling

Abstract

In the context of plant disease management, biocontrol is often used as an environmentally friendly alternative to synthetic chemical pesticides. The genus Trichoderma is known for its ability to suppress various plant diseases caused by pathogenic fungi through antagonism, competition, and induced resistance. This research attempt was to evaluate the mechanisms employed by Trichoderma virens isolate (KP985643.1) in controlling three plant pathogenic fungi (Fusarium oxysporum, Colletotrichum gloeosporioides, and Lasiodiplodia theobromae) under in vitro conditions, along with the selection of the best-fitting mathematical models for their interactions. The biocontrol potential of T. virens against the selected plant pathogenic fungi was evaluated using the dual culture method. Further biocontrol mechanism was identified using the analysis of volatile and non-volatile compounds and the hyphal growth patterns. In addition to that the results of the dual culture method were used to analyse the best-fitting growth models for each pathogenic fungus separately for two conditions which were in the absence of T. virens and in the presence of T. virens. These mathematical models of microbial growth serve as powerful tools for predicting the future performance of fungal biocontrol agents in managing plant diseases under diverse environmental conditions. Such predictive capabilities are crucial for optimizing field applications, improving consistency in biocontrol outcomes, and supporting the development of sustainable, environmentally friendly plant disease management strategies in agricultural systems. Results of the dual culture experiment demonstrated a significant growth control of L. theobromae and F. oxysporum and a moderate growth control of C. gloeosporioides by T. virens. Considering the growth models, the best fitted models were given by Gompertz, Exponential, and Exponential, respectively, for C. gloeosporioides, F. oxysporum, and L. theobromae in the absent condition of T. virens. In the present condition of T. virens, the best-fitted models were given by Brody, Exponential, and Brody respectively for L. theobromae, C. gloeosporioides, and F. oxysporum. The increase in volatile production was not uniform across all pathogens. For instance, the highest VOC production showed against F. oxysporum, suggesting that T. virens may be more efficient at preventing F. oxysporum from producing volatile compounds. Among many VOCs, ethanol and 6-Pentyl-2H-6-Pentyl-2H-pyran-2-one production were the highest when T. virens controlled the growth of F. oxysporum. However, non-volatile compounds produced by T. virens significantly controlled the growth of L. theobromae, with a moderate inhibition of F. oxysporum. It was further observed the ability of T. virens to inhibit the growth of L. theobromae through the production of coiling structures. Results of the present study clearly indicated the potential of T. virens in controlling the tested phytopathogenic fungi by employing a combination of mechanisms including the production of volatile and non-volatile compounds and hyphal interactions.