- Committee for study of microbiomes associated with plants 

There are approximately 300,000 plant species on the earth, each hosting a wide range of microorganisms. The microbial community associated with plants can interact at different levels with its host, colonizing the surface of roots (rhizoplane), shoots (epiphytic community), internal plant tissues (endophytic community) or live in the soil region in contact with roots or under the influence of exudates of these plants (rhizospheric community). The diversity of microorganisms associated with plants is influenced by the species, genotype and physiological conditions of the plant and physicochemical properties of the soil. The abundance of different groups will vary over the different niches found in the plant and due to availability of nutrients, atmospheric conditions and competition with other members of this community. 

Microorganisms can provide benefits to their hosts, such as tolerance to temperature and salinity and protection against pathogenic microorganisms. They can also act in promoting plant growth by producing phytohormones such as indole acetic acid (IAA), solubilizing organic and inorganic phosphate and/or fixing atmospheric nitrogen. These bacteria are denominated Plant Growth-Promoting Rhizobacteria (PGPR) when associated with the root or rhizosphere. Several studies have been conducted in order to select PGPR for use as bioinoculants in different plants.

In addition to using traditional cultivation methods, essential for the development of bioinoculants, the use of molecular biology techniques has opened new perspectives for studying microbial communities. Considering our ability to isolate and grow only 1 to 10% of microorganisms in the laboratory, this strategy offers an alternative to exploitation of the metabolic potential of other microorganisms (99-90%). Even with the possibility to more accurately explore the ecological role of microbiota components, few plant species have been studied in relation to their community of associated microorganisms. Thus, it is also sought to consider the possibility of encountering new microorganisms of biotechnological interest among the thousands of plants in different environments and ecosystems.