Rice domestication-associated miRNA 397 targets laccases to facilitate lignin biosynthesis and yield-related traits [RNA-seq]

MicroRNAs (miRNAs) are a class of 21 nt non-coding small RNAs (sRNAs) produced from endogenously expressed MIR genes. MiRNAs are mostly involved in development and disease resistance. To know the involvement of miRNAs during domestication of rice, sRNA sequencing of two wild species (O. nivara and O. rufipogon), one landrace (O. sativa chomala) and one cultivated species of rice (O. sativa indica Pusa Basmati-1) was carried out. Analysis of sRNA datasets revealed a surprisingly higher abundance of 22nt sRNAs originating from a loci on Chromosome 2 in wild rice species. This locus codes for a 22 nt miRNA named as miR397. Studies in Arabidopsis and O. sativa japonica nipponbare have shown that miR397 targets a group of proteins called laccases, which are involved in secondary metabolite (lignin) production. The expression of these targets also differs across the species shown through RNA-Seq analysis. Although a functional significance of this interaction between the miRNA and laccase has not been understood. In the current study we attempt to explain the functional relevance of the miRNA in domestication of rice. Overall design: We have performed RNA seq analysis using reproductive tissues (flagleaf and panicle) of various rice species. Libraries were prepared from total RNA isolated from the tissues mentioned.