Diversidade e produção de ácido abscísico por fungos endofíticos associados a Goniorrhachis marginata Taub. E Cavanillesia arborea K. Shum

Abstract

The endophytic fungi are microorganisms that settle the inner part of the plant tissues in at least one phase of their development and establish a relationship that apparently is not harmful to the hosts. The interaction with endophytic fungi is present in most of the plant species and has influence in their biological mechanisms as the production of secondary metabolites and the defense against herbivores and pathogens. There are some perspectives that the endophytic fungi can occur widely in rain forests due to the high diversity of plant species and to the several kinds of vegetation present in these places. This paper aimed to evaluate the endophytic fungi diversity associated with Goniorrhachis marginata and Cavanillesia arborea and their abscisic acid production (ABA) throughout the foliage cycle of the two species of trees. The endophytic fungi were isolated from leaves of 10 individuals of both species and grouped into morphospecies. The ABA production by the fungi was detected by liquid chromatography (HPLC). From the leaf material collected from C arborea and G. marginata it was obtained the total of 179 isolated endophytic fungi grouped into 31 morphospecies. The abundance of endophytic fungi isolated was significantly higherin mature leaves over young leaves for both tree species, corroborating with other studies. The fungi community of C.arborea differed from the fungi community isolated from G. marginata. The same was observed in relation to the fungi community isolated from young and mature leaves of the two tree species, demonstrating that there was an influence of temporal variation in these communities. Regarding the ABA production, from the 33 morphospecies characterized in this study, 15 produced this phytohormone. The production of ABA by the endophytic fungi may be related to a colonization strategy used by the analyzed fungi, as it has already been demonstrated in other studies, with the ABA increasing concentrations, the leaves become more susceptible to infection and perennial colonization