Plant growth promotion by rhizobacteria of guarana.

Abstract

The Guarana is the most important cultivated plant in the Amazonian region. Its use is not restricted to the inhabitants of the region, since it handles several economic sectors such as pharmaceuticals, cosmetics and especially the soft drinks industry and other sectors of the food industry.The fruit contains stimulants such as caffeine, that print to Guarana a high exploration potential, since this is one of the most widely consumed stimulant in the world. Despite its importance, this culture is a little studied, and of which little is known about its genetics and microbial interactions. The plant growth promoting rhizobacteria in plants (RPCPs) are bacteria that live in the rhizosphere, in the region of the soil under the root, and that promote plant associated growth. The introduction of these rhizobacteria in the soil brings direct benefits to agricultural production and, at the same time, an alternative crop with less use of agricultural inputs. This research project aims at the isolation of bacteria from the rhizosphere of Guarana and then their identification by sequencing the 16s rDNA. The same will also be evaluated for potential to promote plant growth by increasing the availability of nutrients or by producing inhibitors of pathogens. Phosphate solubilization, siderophore, indole acetic acid (IAA) and biological nitrogen fixation tests will be performed with the rhizobacteria. Then the isolates with the potential to promote plant growth will be inoculated seedlings in the greenhouse. Finally, will perform a monitoring of the Guarana plant colonization and cross-colonization of other cultures of economic interest (such as soy and sugarcane) by growth promoting bacteria using a biomarker (the gene of GFP-Green Fluorescence Protein) and qPCR technique. Results obtained previously allowed to observe the production of compounds related to plant growth promotion by rhizobacteria of guarana. More than 100 isolates have been identified and evaluated for phosphate solubilization and nitrogen fixation. This work is part of a project entitled "Microorganisms associated to guarana with agricultural and biotechnology potential, especially for the control of anthracnose" (Process n. 09/53376-2) which was approved by FAPESP(Research Support Foundation of the São Paulo) in partnership with FAPEAM (Research Support Foundation of the Amazon).