Ilex paraguariensis hosts root-Trichoderma-spp. with plant-growth-promoting traits: characterization as biological control agents and biofertilizers

LOPEZ, A.C.; GIORGIO, E. M.; VERESCHUK, L.M.; ZAPATA, P.D.; LUNA, M.F.; ALVARENGA, A. E.

CURRENT MICROBIOLOGY

SPRINGER

Lugar: Berlin; Año: 2023

0343-8651

In this study, the role of native plant growth-promoting microorganisms (PGPM) as bio-inoculants was assessed as an alternative to improve Ilex paraguariensis St. Hil. growth in the nursery. Fourteen Trichoderma strains isolated from yerba mate roots were evaluated in vitro for their potential as biological control agents (BCA) and PGPM. The PGPM properties were evaluated through the strain’s antagonistic activity against three fungal pathogens (Alternaria sp., F. oxysporum, and F. solani) plus the production of extracellular cell-wall–degrading enzymes such as chitinase, β-1,3-glucanase, and cellulase. These results were used to calculate different PGPM indices to select the strains with the optimal properties. Four Trichoderma strains: T. asperelloides LBM193, LBM204, LBM206, and Trichoderma sp. LBM202, were selected based on their indirect and direct PGPM properties used in an inoculation assay on yerba-mate plants under greenhouse conditions. A highly significant positive effect of bio-inoculation with the native isolates was observed in one-year-old seedlings. The plants treated with Trichoderma exhibited a greater height, chlorophyll content, and dry weight; those treated with LBM193 manifested the best results. Yerba mate plants treated with LBM202 exhibited a healthy appearance and were more vigorous, showing potential for plant growth promotion. In conclusion, the rhizosphere of yerba-mate in the Misiones region was found to have a reservoir of Trichoderma species that increases the yield of this crop in the nursery and protects those individuals from adverse biotic influence and abiotic agents. This could represent a promising sustainable strategy to improve yerba mate growth in low-fertility soils.