Trichoderma longibrachiatum as a biostimulant of micropropagated banana seedlings under acclimatization.

The use of growth-promoting microorganisms with biostimulant characteristics is an important biological asset for the acclimatization of micropropagated seedlings. The present study aimed to evaluate the efficacy of the application of Trichoderma spp. on the promotion of the growth of micropropagated banana seedlings during acclimatization. The experiment was performed in an 8 × 6 completely randomized design using the following treatments: water, seedlings fertilized with controlled-release fertilizer, commercial biological inputs (A: T. asperellum, B/C: T. harzianum), and LPPC299 and LPPC300 strains. Plant height, pseudostem diameter, number of leaves, total leaf area, root length, fresh and dry mass of the plant, and accumulation of sodium, macronutrients, and micronutrients were evaluated 60 days after inoculation. Strains LPPC299 and LPPC300 were subjected to molecular identification by DNA sequencing of the ITS/5.8S locus. In vitro detection of growth promotion-related mechanisms and mycelial growth of biostimulants were performed using scanning electron microscopy. LPPC299 and LPPC300 had a greater similarity to T. longibrachiatum. LPPC299 was able to promote greater pseudostem diameter, number of leaves, and total leaf area in banana seedlings. T. asperellum (A) favored seedling performance in terms of fresh and dry mass of the plants. The strains were able to produce siderophores, indoleacetic acid, and catalase in vitro. Seedlings inoculated with the strains accumulated Mn, S (LPPC300), and Mg (LPPC299). LPPC299 from the banana rhizosphere was efficient in promoting performance in banana seedlings, showing its potential as a biostimulant for this crop.