MicroRNA Networks in Plant-Microorganism Interactions

MicroRNA constitutes an important class of small RNAs that negative regulates post-transcriptionally protein-coding genes. MiRNA-guided gene regulation has been reported as essential for developmental processes and for plant proper responses to biotic and abiotic stresses. When plants are exposed to microorganisms, they resort to various strategies to either establish a beneficial association, or to fight against pathogenic infection. These strategies include changes in metabolic pathways and modifications in gene expression states, which can be achieved by the action of miRNA-guided complexes. Plants growing in tropical regions are exposed to numerous biotic factors and can show large differences in miRNA regulation when exposed to either pathogenic or beneficial microorganisms. Recent insights in this field have begun to shed light on the role played by miRNA in plant-microbe associations. Aiming to understand how plants sense the diverse microorganisms, we review here the current knowledge of the roles played by miRNAs during plant-microbe interactions, focusing in results of studies carried out with tropical plants.