Responses of the sugarcane rhizosphere microbiota to different levels of water stress

The production of sugarcane, a globally important crop, is likely to be impacted by changes in climate including higher average temperatures and decreased rainfall in regions such as the northeast and southeast of Brazil. This metatranscriptome study investigated the effect of water stress on the microbiota associated with the sugarcane rhizosphere, in order to obtain new information about plant-microbiota interactions and the ways that microorganisms could help plants to survive under adverse conditions. The results indicated that water stress increased the exudation of organic acids from the plant roots and changed the microbial gene expression in the rhizosphere. Decreased expression of genes related to growth and energy metabolism was mainly evident in samples submitted to eight days of water stress and was classified to the genera Sorangium and Rhodanobacter. Genes associated with functions such as flagella mobility, cell adhesion, and protein degradation showed increased expression in the same time period, with these transcripts classified to the genus Aequorivita. This genus also showed a positive correlation with the organic acids exuded by the plant. These results contribute to an understanding of the dynamics of the rhizosphere microbial community under normal and water stress conditions, indicating possible microbial groups that may play important roles in the maintenance of sugarcane under water stress.