New strains of Trichoderma with potential for biocontrol and plant growth promotion improve early soybean growth and development

Abstract

Aims Bioformulations with Trichoderma strains offer cost-effective and sustainable options for integrated disease management and plant nutrition. Therefore, this study aimed selected new isolates of Trichoderma with antagonistic and plant growth promotion abilities, including the effect of inoculation of isolates on the early development of soybean seedlings. Methods Trichoderma isolated from the soybean rhizosphere were screenings assessed their antagonistic activity against three phytopathogens, as well as their capability for indole-3-acetic acid (IAA) synthesis and phosphate solubilization. Three promising isolates were further examined for their tolerance to various in vitro conditions and agrochemicals. Single and co-inoculation experiments to assess their effects on growth, chlorophyll, carotenoids, proteins, flavonoids, and phenolic compounds during early soybean development. Results T. viride GT-8, T. reesei GT-31, and T. longibrachiatum GT-32 demonstrated antagonism against phytopathogens. GT-31 and GT-32 exhibited higher IAA synthesis (175.8 ± 2.4 µg/mL and 119.6 ± 11.2 µg/mL, respectively), while GT-8 showed superior phosphate solubilization (28.56 ± 0.4 µg P/mL). All three fungi displayed robust growth under various conditions and agrochemical treatments. Trichoderma inoculation significantly enhanced shoot and root growth, with co-inoculation resulting in even higher dry shoot and root weights, increasing by 50.3% and 48.8%, respectively, compared to non-inoculated seedlings. Trichoderma-inoculated plants also exhibited elevated chlorophyll, carotenoids, flavonoids, and phenolic compounds. Conclusion Overall, these findings highlight the potential of these novel Trichoderma isolates for formulating bioformulations that can enhance plant growth and offer benefits in soybean crops, providing a sustainable strategy for agriculture.