Influence of plant exudates on the ecology of Methylobacterium spp. during interaction with the host plant

Abstract

The genus Methylobacterium corresponds a group of methylotrophic Gram negative bacteria, which grow in pink pigmented colonies due the synthesis of carotenoids, being known as Pink pigmented facultative methylotrophic bacteria (PPFM). Bacteria belonging to this genus can be observed in association with different plant species, in which they can act as bio-control agents and/or growth promoters, through the production of plant regulators and the availability of nutrients. For this, it has been observed that the cross-talking between Methylobacterium and the host plant should be related to this interaction, probably through the root exudates of the plant, which select beneficial microorganisms. However, the molecular mechanisms involved are still unclear, especially those that determine the specificities in the bacterium-plant interaction. Thus, the aim of the present study is to analyze the growth of different Methylobacterium species under the influence of exudates produced by corn (Zea mays), soybean (Glycine max) and red pepper (Capsicum annuum) plants. For this, 5 species of Methylobacterium will be selected by an initial screening of competitiveness; these bacteria will be inoculated individually or in groups in the host plants. The colonization of the host plant by these bacteria will be evaluated by qPCR using specific primers for each isolate; the composition of the plant exudates will also be identified by gas-chromatography. On the other hand, the change in soil bacterial diversity in the presence of different selected bacteria will be evaluated by DGGE. Finally, through genome analysis of these bacteria, genetic mechanisms associated to competences and specificity will be evaluated. (AU)