Transcriptomic responses of sugarcane to drought stress are modulated by bacterial synthetic communities

Drought intensification due to climate change poses a significant constraint on global sugarcane production, as the crop requires substantial water for optimal growth. Synthetic Communities (SynComs) have the potential to enhance drought resilience, yet their application and mechanisms of action remain unclear, particularly in sugarcane. In this study, transcriptomic analysis was employed to investigate how SynComs modulate responses to drought stress in sugarcane. Five potential SynComs (SC) were evaluated, and SC3 was selected for detailed gene expression analysis based on its relatively higher microbial diversity and community evenness as indicated by the Shannon diversity and Pielou's evenness indices, together with its ability to promote sugarcane growth and physiological processes. SC3 was associated with increased plant height, phosphorus uptake, and osmoprotectant content compared with the other SynComs. Transcriptomic analysis revealed differences in signal transduction: in SC3-inoculated plants, MAPK signaling was prominent, whereas in control plants, signaling relied more on plant hormones. Additionally, differences in energy allocation and secondary metabolite production as defense responses to drought stress were observed. SC3-treated plants allocated energy to maintaining lipid membrane integrity and lignification, while control plants focused on antioxidant activity via flavonoids. These results indicate that bacterial SynCom inoculants can modulate drought stress responses. Overall, the findings highlight the potential of SynComs as a sustainable microbial strategy for enhancing crop performance under drought stress.