Synergia between Trichoderma harzianum and plant extracts for the generation of agroecological bioinoculants.

CALUMBY, R.; ; BUTASSI, E., ; SVETAZ, L.; ; SORTINO, M.; ; CHIESA, A., ; RIUS, S.; ; CAMPOS-BERMUDEZ, V. A.

Congreso; LVIII Annual Meeting of the Argentine Society for Biochemisty and Molecular Biology Research.; 2022

In order to reduce losses in crop productivity and ensure the quality of the grains, the control of diseasescaused by pathogens is one of the main factors to be considered. One of the strategies currently usedfor disease management is the use of synthetic agrochemicals, which is controversial due to their harmful effects in human health and the environment. In this sense, the use of natural agents and compounds for the biological control of plant diseases is increasingly in demand. Several beneficialmicroorganisms, such as Trichoderma, and different plant-derived extracts have individually shownantagonistic effects against different phytopathogenic organisms. In addition, some of them have shownthey have an impact on crop productivity. The aim of this work was to evaluate the synergistic effect of acoculture of Trichoderma and vegetal extracts in the reduction of plant diseases and tomato andsoybean growth promotion. For this purpose, three minimal media were prepared as follows: 1- vegetalextract of Larrea nitida Cav. (Zygophyllaceae); 2- strain of Trichoderma harzianum (1x106 conidia/mL); and3- a mix of the components used for the conditions 1 and 2. After incubation at 28°C under agitation for 7days, the cultures were vacuum filtered through a 0.20 µm membrane to eliminate the fungal biomass.The filtrates obtained were used to evaluate the antifungal activity against two fungal phytopathogens (Fusarium oxysporum and Diaporthe caulivora) and also to evaluate plant growth promotion byinoculating the filtrates in soybean and tomato seeds. Subsequently, chromatographic separation wascarried out to obtain the metabolic profile of the organic extractions. The results obtained indicated agreater inhibition of the growth of F. oxysporum and D. caulivora in the presence of the filtrate of T.harzianum in association with the plant extract, evidencing an activity-enhancing effect, compared tousing each component separately. Similar results were observed for the tests of plant growth promotionin soybean and tomato, showing greater germination of seeds, plant development and biomass of aerialparts. Regarding the metabolic profile, there were differences in the chromatographic pattern betweenthe Trichoderma filtrate alone and in the presence of plant extract, with some bands being observed withgreater intensity under ultraviolet light at 365 nm and others with less intensity under ultraviolet light at254 nm. These results show an enhancing effect of the activity of the consortium formed by Trichodermaand the plant extract for the control of phytopathogenic fungi, the promotion of plant growth, and theagronomic performance of tomato and soybean, suggesting its potential use as an agricultural bioinoculant.