microRNAs and Mechanical Stress

Abstract

Mechanical stress, one of the major abiotic stresses, significantly affects plant growth, survival, and reproduction. Recent studies showed that cytoplasmic calcium, reactive oxygen species, and phytohormones play important roles in mechanosensing and subsequent anatomical and morphological changes in plants exposed to mechanical stress. A large number of mechanical stress-responsive genes, particularly those involved in reaction wood formation in tree species, have been isolated and characterized. Importantly, a group of mechanical stress-responsive miRNAs was identified in Populus trichocarpa plants. They were predicted or experimentally validated to regulate genes encoding transcription factors, metabolism and cellular process-related proteins, and many functionun-known proteins. Analyses of miRNA expression patterns and target gene functions indicate that miRNAs play crucial regulatory roles in reaction wood formation. Recent results provide novel and useful information for fully elucidating the genetic and molecular mechanisms of plant responses to mechanical stress.