Investigating the secondary metabolism of Brasilonema (Cyanobacteria: Scytonemataceae)

Abstract

Brasilonema is a cyanobacterial genus in which the only known oxyphotobacteria known to infect plants are classified. The study of genomes from micro-organisms of this genus may bring several contributions, including a better understanding of the diversity of cyanobacterial secondary metabolism and the possible role of their bioactive molecules. Previously, as part of the project "Comparative genomics of Brasilonema (Cyanobacteria, Scytonemataceae) strains for the identification of genes related to Eucalyptus grandis leaf infection" (FAPESP #2015/146005), a considerable number of gene clusters predicted as involved in secondary metabolism have been identified in the genomes from two Brasilonema spp. strains. The aim of this research proposal is to analyze the secondary metabolites produced by strains B. octagenarum UFV-E1 and B. sennae CENA114 and to identify putative gene clusters encoding enzymes involved in their biosynthesis. For this purpose, cells from UFVE1 and CENA114 cultures will be grown in liquid BG-110 medium for three weeks and used for the production of raw extracts, which will have their capacity of inhibiting microbial pathogen strains tested. Positive extracts will be fractioned and subjected to liquid chromatography/mass spectrometry analyses for structural identification. The characterized molecules will then be correlated to predicted clusters containing genes for their putative biosynthetic enzymes. It is expected that novel molecules and/or new variants of known molecules produced by Brasilonema strains are found and successfully assigned to their putative biosynthetic pathways.