Multifunctional Traits of Trichoderma afroharzianum ISO-02 and Trichoderma brevicrassum ISO-03 Promoting Wheat Growth...

Wheat as a major staple crop faces productivity constraints, especially in rain-fed and arid areas of Pakistan. Ecofriendly alternatives using indigenous plant growth promoting (PGP) microorganisms may help enhance crop performance. This study evaluated PGP traits of indigenous strains of two under-characterized Trichoderma species, that is, Trichoderma afroharzianum ISO-02 and Trichoderma brevicrassum ISO-03, using in vitro and in planta assays with cell-free culture filtrates (CFCF) or spore-based formulations. To the best of our knowledge, this is the first comparative study evaluating CFCF and spore-based formulations of strains of T. afroharzianum and T. brevicrassum on wheat growth. Briefly, ISO-02 produced higher levels of IAA (9.91 µg/mL) and ammonia (11.63 µg/mL) than ISO-03. Moreover, ISO-02 exhibited significantly higher phosphate (1.15 ± 0.01 mm) and zinc-solubilization indices (1.46 ± 0.03 mm), and produced pectinolytic enzymes and siderophores. The CFCF, or spore suspensions of ISO-02, both in plates and pots, produced significantly higher germination, with increased chlorophyll contents and growth parameters on a consistent basis at p ≤ 0.05. The results also suggested a role of extracellular metabolites in growth stimulation of wheat. The present study demonstrated multifunctional PGP traits of T. afroharzianum ISO-02 and T. brevicrassum ISO-03, supporting their potential application as sustainable biofertilizers specifically for wheat cultivation.