Application of Trichoderma species increases plant salinity resistance: a bibliometric analysis and a meta-analysis

Purpose: Soil salinization has become increasingly serious recently, leading to a significant decline in crop yields. Application of Trichoderma species can enhance plant salinity resistance and thus achieve greater yields. However, there are few relevant studies. Here, we conducted a bibliometric analysis of relevant articles to reveal the current research status, and then carried out a meta-analysis to investigate the potential mechanisms. Methods: We analyzed the relevant databases using bibliometric analysis and meta-analysis. Results: The bibliometric analysis revealed that there are relatively few studies on the enhancement of plant salt resistance through Trichoderma species. The meta-analysis revealed that inoculation with Trichoderma under salt stress significantly changed morphological indicators, physiological indicators and enzyme activity in plants. Moreover, through subgroup analysis, we also found that when plants experienced moderate salinity (4–8 dS m⁻¹) and medium-term (2–4 weeks) salt stress, the application of Trichoderma species had the greatest promoting effects. Inoculation with Trichoderma was more effective on plants that were monocotyledons or C₄ plants. Among the various Trichoderma strains, T. hamatum had the best inoculation effect. Conclusions: Trichoderma species can promote plant growth under salt stress and improve plant salinity resistance through three main pathways: (1) promoting the development of the roots to absorb more nutrients and water, (2) increasing the activity of antioxidant enzymes to scavenge excess reactive oxygen species, and (3) enhancing the performance of Photosystem II to improve plant photosynthetic capacity. Moreover, through subgroup analysis, we also found that inoculation with Trichoderma species can be affected by various factors, such as salinity, duration of salinity, plant groups, photosynthetic type, and Trichoderma species.