Transcriptional regulation of plant sugar transporter genes by beneficial rhizobacteria

In their natural environment, plants live in close interaction with complex populations of microorganisms, including rhizobacteria species commonly referred to as ‘Plant Growth Promoting Rhizobacteria’ (PGPR). A growing body of evidence demonstrates the importance of sugar transport in plant pathogen resistance and in plant-microorganism mutualistic symbioses. Using an <i>in vitro</i> experimental system, including the model plant species <i>Arabidopsis thaliana</i>, two PGPR strains (<i>Pseudomonas simiae</i> PICF7 and <i>Burkholderia phytofirmans</i> PsJN) and a non-PGPR strain (<i>Escherichia coli</i>), we conducted a comprehensive set of phenotypic and gene expression analyses to explore the role and regulation of sugar transporter genes in plant-PGPR interactions. In physical contact with the seedling roots, or solely <i>via</i> the emission of bacterial volatile compounds, the two PGPR strains tested improved the growth and development of the Arabidopsis seedlings and altered the expression of several plant sugar transporter genes. Our results also revealed both conserved and strain-specific transcriptional regulation mechanisms.