MicroRNAs meet with quantitative trait loci: Small powerful players in regulating quantitative yield traits in rice.

MicroRNAs (miRNAs) are small noncoding RNAs which regulate various functions related to growth, development, and stress responses in plants and animals. Rice, Oryza sativa, is one of the most important food crops of the world. In rice, a number of quantitative trait loci (QTL) controlling yield-related traits have been identified. Some of them are actually controlled by miRNAs, which control various yield-related quantitative traits in rice. On one hand, many of these miRNAs are found to regulate more than one yield-related traits, such as tillering, grain size, and branch number of a panicle. On the other hand, a rice yield-related trait is usually controlled by multiple miRNAs, for example, grain size being controlled by miR156, miR167, miR396, miR397, and miR1432. In rare case, a single miRNA may specifically regulate only one yield-related trait, such as, miR444 regulating rice tillering. In this review, we focus on the functions of miRNAs in controlling yield-related quantitative traits in rice, including panicle grain number, grain weight/size, panicle length and branching, tiller number per plant, spikelet number, seed setting rate, and leaf inclination, and discuss how to modulate the expression of these miRNAs using modern molecular biology tools to promote grain yield. This article is categorized under: RNA in Disease and Development > RNA in Development.