Isolation and Characterization of Pseudomonas chlororaphis Strain ST9; Rhizomicrobiota and in Planta Studies

The development of biotechnologies based on beneficial microorganisms for improvingsoil fertility and crop yields could help to address many current agriculture challenges, such asfood security, climate change, pest control, soil depletion while decreasing the use of chemicalfertilizers and pesticides. Plant growth-promoting (PGP) microbes can be used as probiotics in orderto increase plant tolerance/resistance to abiotic/biotic stresses and in this context strains belongingto the Pseudomonas chlororaphis group have shown to have potential as PGP candidates. In this studya new P. chlororaphis isolate is reported and tested for (i) in vitro PGP features, (ii) whole-genomesequence analysis, and (iii) its effects on the rhizosphere microbiota composition, plant growth, anddifferent plant genes expression levels in greenhouse experiments. Results showed that P. chlororaphisST9 is an efficient rice root colonizer which integrates into the plant resident-microbiota and affectsthe expression of several plant genes. The potential use of this P. chlororaphis strain as a plant probioticis discussed.