Microarray-based Analysis of Tomato miRNA Regulated by Botrytis cinerea

Botrytis cinerea Pers.:Fr. is an important pathogen in tomato plants that causes stem rot of tomatoes grown indoors for an extended period. MicroRNAs (miRNAs) have recently been reported as a class of gene expression regulators linked to stress responses; however, data on the role of miRNAs in plant responses to biotic stresses are still limited. In this study, three Botrytis stress-responsive miRNAs were identified using microarray analysis and the effects of Botrytis infection were surveyed in tomatoes. Two downregulated miRNAs and one upregulated miRNA were detected. These stress-responsive miRNAs regulated metabolic, morphological, and physiological adaptations of tomato seedlings at the post-transcriptional level. The presence of stress-related elements in the miRNA promoter regions further supports our results. These findings extend the current view about miRNAs as ubiquitous regulators under stress conditions.