Chemical study of the secondary metabolites produced by endophytic microorganisms isolated from banana, pear and guava

Abstract

Microorganisms can leave associated with many vegetal source without causing any apparent disease symptoms. In general, in these cases, these microorganisms are referred as mutualistic stage endophyte. However, these same microorganisms may become phytopatogens when the immunologic system of the host plant is not able to control its development. Although only a few studies have been done on the biochemical aspects of these different stages of plant-microorganisms associations, it has been observed that the microorganism’s metabolism may be active and producing chemicals that are accumulated in the host tissue. These chemicals may show many different effects in humans according the type/specie of the producing microorganism. The present master level project, proposed for the student Lívia Soman de Medeiros, has as the main goal an study of the production of secondary metabolites by endophytic microorganisms found in banana (Musa paradisiaca), pear (Pyrus sp) and guava (Psidium guajava). The literature shows some works with these plants. However those studies deal with other organs such as leaf and roots, in more agronomic than chemistry point of view. The present work proposal is intended to study the microbiology/chemistry of the edible part of the fruits. Our main objective is to isolate endophytic microorganisms; to verify their potential for the production of secondary metabolites in artificial culture medium and medium containing fruit pulp; to investigate the antibiotic properties of these constituents; and finally, to check whether these compounds are present in the edible fruits. In preliminary studies, the microbiot of these fruits was sampled and a few assays in order to find a good cultivation condition as well as a few chemical analyses were already done. The development of the project will require intense use of diverse chromatographic techniques, mass spectrometry and NMR spectroscopy. The establishment of a good background in these organic analyses and in the interpretation and contextualization of the results is the main educative aim in the MS project proposed for the student Lívia S. de Medeiros. (AU)