Selection of endophytes as antagonists of Colletotrichum gloeosporioides in açaí palm

Abstract

Foliar endophytic fungi may share the same habitat of phytopathogens and develop a key role in plants defense. Colletotrichum gloeosporioides is the causal agent of anthracnose in açaí palms (Euterpe precatoria Mart.), affecting severely the leaflets of this plant. Here, we report the first investigation on the fungal endophytic community associated with the leaflets of E. precatoria in native and cultivated habitats in the Western Amazonia, using culture-dependent method. We also identified potential C. gloeosporioides-antagonist foliar endophytic fungi using dual culture and açaí leaflets detached assays. Our data revealed that the composition of the fungal community in E. precatoria was influenced by cultivation system of these plants, and the native plants sampled exhibited higher levels of fungal diversity compared to the cultivated plants. The morphotype Colletotrichum sp. 11, probably a latent pathogen (C. gloeosporioides), was the most abundant endophyte species and was obtained from all samples of planted açaí palms. A total of 151 endophytes were able to inhibit in vitro growth of C. gloeosporioides, indicating different kinds of antagonism such as competition, mycoparasitism and antibiosis. Among the endophytic fungi tested in the detached leaflet assay, Ramichloridium sp., recovered from native E. precatoria, showed a greater ability in the control of anthracnose. Altogether, this study suggests that the Ramichloridium sp. isolate can be a promising candidate for the biological control of C. gloeosporioides and that E. precatoria can host endophytic fungi that help in the defense against phytopathogenic fungi.