Potencial controle biológico de fitopatógenos por Trichoderma Harzianum P49P11

Abstract

The study of new biological control microorganisms aims to obtain a product with a specific action and with greater capacity to control plant diseases and the pests, but that lowers the economic and environmental impacts caused by pesticides. The Trichoderma harzianum P49P11 strain, isolated from Amazonian soil, had its enzymatic potential evaluated in biomass degradation processes, it is well known that genus can generate bioactive compounds and controlling characters of other microorganisms. Thus, the study aimed to identify the biological control of phytopathogen by T. harzianum P49P11 strain. Lytic enzymes were evaluated by cultivating the strain in 6 different selective media for 3 days at 28ºC, after this period showed growth, characterizing the enzymatic production, however there was no formation of enzymatic halo to quantify the enzymatic activity. In Potato Dextrose Agar medium, the Biological Control Agent Co-cultivated against 17 phytopathogens, presented an inhibition of 50% for Colletotrichum sp. FP9 (65.7%), Fusarium oxysporum bean FP11 (55.8%), Phytophthora sojae FP13 (75%) and Lasiodiplodia euphorbicola FP16 (56.3%), highlighting the inhibition of the FP13 strain (75%) by the ACB during work, characterizing the second most inhibited phytopathogen in this work. Co-cultivation in Czapek medium inhibited the Fusarium oxysporum ATTCC 2163 FP4 (51.7%), Alternaria alternata FP7 (52.1%), Fusarium proliferatum FP8 (51.8%) and Fusarium oxysporum bean FP11 (51.7%), Phytophthora sojae FP13 (54.5%) and Rhizopus microsporus FP14 (83.3%). Highlighting the inhibitory action of ACB on the FP 14 strain that reached the highest inhibition during the work, however, may have occurred during the adaptation of the phytopathogen strain to the Czapek medium. For MeOH/EtOAc extraction, the P49P11 strain was grown in Potato Dextrose liquid medium for 7 days at 28 ° C, pH 5 and stirring at 120 rpm to obtain fermentation broth. After this cultivation time, the broth was centrifuged under 10,000 rpm and the supernatant was collected for extraction. Amberlite® XAD-16 resin was used for the extraction of the possibly bioactive compounds in the fermentation broth, the extract being eluted with 1: 1 MeOH/EtOAc for evaluation of inhibition. The phytopathogens inhibited in the previous tests were not responsive to the extract. However, the performance of the controlling strain T. harzianum P49P11 is highlighted for strains FP 14 and FP 13, being a candidate strain of Phytophthora sojae and for future testing with the ACB strain.