Plant growth-promoting bacteria in the rhizo- and endosphere of plants: Their role, colonization, mechanisms involved and prospects for utilization

• Published in: Soil biology & biochemistry 2010-05, Vol.42 (5), p.669-678
• Main Authors: Compant, Stéphane, Clément, Christophe, Sessitsch, Angela
• Format: Article
• Language: English
• Subjects: aerial parts; Agronomy. Soil science and plant productions; Biochemistry and biology; biofertilizers; Biological and medical sciences; biological control agents; Chemical, physicochemical, biochemical and biological properties; crops; endophytes; Endophytic bacteria; Fundamental and applied biological sciences. Psychology; literature reviews; microbial colonization; Microbiology; Physics, chemistry, biochemistry and biology of agricultural and forest soils; phytoremediation; Plant colonization; plant growth; plant growth-promoting bacteria; plant growth-promoting rhizobacteria; plants; rhizoplane; Rhizosphere bacteria; root inoculation; soil inoculation; Soil science; translocation (plant physiology)
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2009.11.024

In both managed and natural ecosystems, beneficial plant-associated bacteria play a key role in supporting and/or increasing plant health and growth. Plant growth-promoting bacteria (PGPB) can be applied in agricultural production or for the phytoremediation of pollutants. However, because of their capacity to confer plant beneficial effects, efficient colonization of the plant environment is of utmost importance. The majority of plant-associated bacteria derives from the soil environment. They may migrate to the rhizosphere and subsequently the rhizoplane of their hosts before they are able to show beneficial effects. Some rhizoplane colonizing bacteria can also penetrate plant roots, and some strains may move to aerial plant parts, with a decreasing bacterial density in comparison to rhizosphere or root colonizing populations. A better understanding on colonization processes has been obtained mostly by microscopic visualisation as well as by analysing the characteristics of mutants carrying disfunctional genes potentially involved in colonization. In this review we describe the individual steps of plant colonization and survey the known mechanisms responsible for rhizosphere and endophytic competence. The understanding of colonization processes is important to better predict how bacteria interact with plants and whether they are likely to establish themselves in the plant environment after field application as biofertilisers or biocontrol agents.