Project description:Cooperation involving Plant Growth-Promoting Rhizobacteria results in improvements of plant growth and health. While pathogenic and symbiotic interactions are known to induce transcriptional changes for genes related to plant defense and development, little is known about the impact of phytostimulating rhizobacteria on plant gene expression. In this context, this study aimed at identifying genes significantly regulated in rice roots upon Azospirillum inoculation, considering possible favored interaction between a strain and its original host cultivar. Genome-wide analyses of root gene expression of Oryza sativa japonica cultivars Cigalon and Nipponbare were performed, by using microarrays, seven days post inoculation with A. lipoferum 4B (isolated from Cigalon roots) or Azospirillum sp. B510 (isolated from Nipponbare) and compared to the respective non-inoculated condition.
Project description:Enterobacter sp. SA187 is a plant growth-promoting bacterium (PGPB) that promotes growth of the crop plant alfalfa under saline irrigation and desert farming conditions. SA187 also enhances salt tolerance of the model plant Arabidopsis thaliana under in vitro conditions. In the present study, we used a transcriptomic approach to elucidate the mechanisms underlying plant growth promotion by SA187 under salt stress. Compared to free-living SA187, a massive metabolic reprogramming of SA187 occurs upon association with Arabidopsis. This effect was largely independent of the plant growth condition (non-salt or salt stress). Our data revealed pronounced changes in gene expression of proteins involved in cell signaling, chemotaxis, flagella biosynthesis, quorum sensing and biofilm formation. Also, upon plant interaction, a complete reprograming of nutrients acquisition and the central carbon metabolism of SA187 was observed. Moreover, in accordance with the previously identified role of bacterially produced 2-keto-4-methylthiobutyric acid (KMBA) in mediating salt stress tolerance, the sulfur metabolism of SA187 was strongly induced. Overall, our results give a deep insight into the metabolic and signaling pathways involved in the transition from free-living to a plant-associated PGPB life style of SA187.
Project description:Small RNAs are the non-coding RNAs known to regulate various biological functions such as stress adaptation, metabolism, virulence as well as pathogenicity across wide range of bacteria, mainly by controlling mRNA stabilization or regulating translation. Identification and functional characterization of sRNAs that has been carried out in various plant growth promoting bacteria have shown to help the bacterial cell cope up with environmental stress. Till now no study has been carried out to uncover these regulatory molecules in diazotrophic alpha-proteobacterium Azospirillum brasilense Sp245. RNA-Seq is a suitable approach for expression-based sRNA identification in bacteria.
