A cluster of miRNAs regulate MYB repressors to promote anthocyanin accumulation in grapes (RNA-Seq)

MicroRNAs are a class of endogeneously expressed non-coding small, ~21nt RNAs involved in the negative regulation of gene expression. In plants, miRNAs are known to play a critical role in developmental and metabolic pathways, as they predominantly target transcription factors. Studies in Arabidopsis and apple have shown that few microRNAs and small interfering (si) RNAs target MYB transcription factors, which are key regulators of phenylpropanoid pathway. However, it is not well-understood how miRNAs mediate regulation of MYBs to produce secondary metabolites such as anthocyanins and flavonoids. Here we show that, a cluster of abundant miRNAs target MYB transcription factors in anthocyanin rich fruits such as grapes. Using RNA-sequencing we establish that grape varieties with high anthocyanin content express abundant MYB-targeting miRNAs resulting in differential expression of MYB proteins among grape varieties, thereby regulating the phenylpropanoid pathway. Overall design: RNA-Seq of three cultivars of grapes with varying levels of anthocyanin.

12

Tirumalai V, Swetha C, Nair A, Pandit A, Shivaprasad PV