WHO IS INSIDE THERE? THE ENDOPHYTIC MICROBIOTA FROM MACAW PALM AND ITS POTENTIAL APPLICATIONS FOR SUSTAINABLE MANAGEMENT

The macaw palm is a native Brazilian tree, globally significant due to its production of large quantities of oil. With the expansion of the crop, plant health problems have been arisen in commercial fields, all of unknown etiology. Using beneficial microorganisms, such as endophytic fungi, to control plant pathogens and promote plant growth can be an important tool in the sustainable management of macaw palms. However, the beneficial microbiota associated with macaw palm has not yet been investigated. This study aimed to elucidate the etiology of the main disease affecting macaw palms in the field and to survey root endophytic fungi associated with the crop with potential sustainable management applications. Plant pathogens were isolated from symptomatic macaw palm tissues, and Koch's postulates were performed to identify the causal agent of the main disease. Endophytic fungi were isolated, subjected to dual culture tests to select plant pathogen antagonists, and inoculated into maize seeds to screen for plant growth promoters. The root and basal stem rot disease affecting macaw palms was identified, and its causal agent is Phytophthora palmivora. A total of 250 endophytic fungi were discovered, three of which demonstrated high inhibition ability (up to 82%) of P. palmivora. Biometric data from maize indicated that at least 10 of the tested endophytic fungi have the potential to promote plant growth. The best isolates were identified and do not belongs to plant pathogenic species, making viable the studies for the development of bio-inputs. Furthermore, we discovered that macaw palms harbor many new taxa of dark septate endophytes, which are fungi able to reduce abiotic stress in plants. The next steps include plant growth promotion tests in macaw palms and the description of new fungal taxa associated with macaw palms. The insights from this study are fundamental for developing biological technologies applicable to crop management.