Diversidade de fungos endofíticos de clones de seringueira e seu potencial para produção de enzimas extracelulares e biocontrole de fungos fitopatogênicos

Abstract

Endophytic fungi are microorganisms that inhabit the internal tissues of plants throughout their life cycle or part of it, without causing apparent damage to the host. These fungi are present in all plants studied so far, and are used in the biocontrol of phytopathogenic fungi, in the production of extracellular enzymes and secondary metabolites of biotechnological interest. Studies with species of the genus Hevea have shown a great diversity of endophytic fungi mainly associated with leaves. The aim of this study was to investigate the diversity of endophytic fungi from rubber tree clones and their potential for biocontrol of phytopathogens and production of extracellular enzymes. The fungi were isolated from healthy leaves of 3 rubber tree clones, the molecular identification of the isolates was done by sequencing the rDNA region (ITS). The selected endophytes were tested in double culture assays against phytopathogens C. cassiicola and Colletotrichum sp. and evaluated for the production of amylase, cellulase, lipase and protease. Data analysis was performed using the R software. 269 endophytic fungi belonging to 47 OTUs and 22 genera were isolated, with Colletotrichum and Diaporthe being the most abundant in the three clones. It was observed that clone C44 presented greater wealth and diversity in relation to the others. Of the endophytic fungi selected for the antagonism test, 85.29% inhibited C. cassiicola growth and 95.09% inhibited the growth of Colletotrichum sp. Isolates 158C and 1A (Cophinforma atrovirens and unidentified) showed greater efficiency in inhibiting the phytopathogens tested. The enzyme synthesis was positive for lipase (69.6%), amylase (67.6%), cellulase (33.3%) and protease (20.6%%). The best enzyme indices were observed for amylase and lipase, IE≥2. With this study it was possible to know the communities of endophytic fungi in the different clones. Clone C44 showed greater diversity and species richness. The isolates obtained from the rubber tree clones showed good antimicrobial and enzymatic potential, which can be extensively tested in the industry, as well as acting in the control of phytopathogens.