microRNA regulation of fruit development, quality formation and stress response

Fruits, as the reproductive organs of many higher plants, are an integral part of a balanced diet, providing rich nutrients and bioactive substances for our health. Over the years, the research on fruit development, quality formation and stress response has deepened, which sheds light on the regulatory mechanism and application of fruit quality improvement. Among the many regulatory factors, microRNAs (miRNAs) are a class of short non-coding RNAs, ranging from 20 to 24-nt, which post-transcriptionally regulate target gene expression. miRNAs and their functions have been extensively examined in plants especially in model species, and they play critical roles in the regulation of diverse biological processes in response to endogenous developmental signals and external environmental cues, respectively. In fruit crops, the function of miRNAs and their regulation have also been under intensive study. In particular, the novel roles of miRNAs that have not been revealed in the model annual species have been unraveling, which reflect the genetic, physiological, and developmental complexity of gene regulation in fruit crops. Here we review the current research progress achieved, specifically in fruit crops, with a focus on the function of miRNAs in the control of fruit development and quality as well as response to various stresses. The future prospects of miRNAs for quality-targeted fruit breeding are also discussed.