Transcriptomic profiling of Arabidopsis Thaliana responses to Stutzerimonas stutzeri, chlorella vulgaris, and mixed consortium inoculation under salt stress.

Plants, constantly exposed to dynamic environmental conditions, encounter various abiotic stresses that significantly affect their growth and development. In response, plants initiate complex physiological and molecular adjustments, including altered gene expression. One of the most influential factors in mitigating stress impacts is the plant-microbe interaction. Among these, plant growth-promoting rhizobacteria (PGPR) are well-studied for their ability to enhance plant resilience. More recently, microalgae have emerged as potential members of the plant microbiome, although their roles remain comparatively underexplored. This study investigates the transcriptomic responses of Arabidopsis thaliana to inoculation with the PGPR strain Stutzerimonas stutzeri, the green microalgae Chlorella vulgaris, and a consortium of both microorganisms under salt stress conditions. Through RNA-seq analysis, we identified a set of core genes commonly regulated across all inoculation treatments, including SALT OVERLY SENSITIVE 3 (SOS3), the potassium channel AKT2, and CBL-INTERACTING PROTEIN KINASE 5 (CIPK5), suggesting a shared stress-mitigation mechanism. Additionally, we identified genes uniquely regulated in response to the S. stutzeri-C. vulgaris consortium. These included components of the ethylene signaling pathway (EIN3/EIL1), detoxification-associated genes such as β-GLUCOSIDASE (BGLU22), and transcription factors linked to stress response, notably NAC6 and MYB12. Together, these findings provide insight into the specific and overlapping transcriptomic changes induced by bacterial, algal, and combined inoculations, contributing to our understanding of plant-microbe interactions under salt stress.