P-418 - Investigating the Molecular Mechanisms via which the Plant Growth-Promoting Bacterium, Azospirillum brasilense, Improves Growth in Salt-Stressed Rice

Major food crops, such as rice and maize, display severe yield losses (30-50%) under salt stress. Therefore, it is necessary to implement sustainable agricultural strategies, such as exploiting beneficial plant-microbe associations, for increased crop yields. Plants develop associations with beneficial microbes, including plant growth-promoting bacteria (PGPB). PGPB like Azospirillum brasilense improves plant growth via multiple mechanisms, including protection against biotic and abiotic stresses. However, little is known about the molecular mechanisms by which A. brasilense mitigates salt stress. Previously, we reported A. brasilense inoculation improves rice growth under high salt concentrations (100 mM and 200 mM NaCl).  We hypothesized that A. brasilense inoculation would regulate the expression of rice genes involved in salt-stress response, and nutrient and ion transport, among others. Using RNA sequencing, we identified the transcriptomic changes in salt-stressed rice upon A. brasilense inoculation after seven days. To identify the early transcriptomic changes in salt-stressed rice upon A. brasilense inoculation, recently we completed an RNA-seq experiment and are currently analyzing the results. In this study, we expect to identify differentially expressed genes in salt-stressed rice involved in the initial perception and response to A. brasilense. Our findings will provide essential insights into salt stress mitigation in rice by A. brasilense.