Conserved miRNAs modulate the expression of potential transcription factors of isoflavonoid biosynthetic pathway in soybean seeds.

Despite the significant importance of soybean isoflavone, the regulatory mechanism of miRNAs during its biosynthesis is highly unexplored. In the present work, nine existing miRNAs along with their ten corresponding target genes were identified and validated in soybean for their possible role during isoflavonoid biosynthesis and accumulation. Temporal expression analysis at four key stages of seed development (35, 45, 55 and 65DAF) of all the miRNA-target pairs showed varying degree of differential accumulation in two soybean genotypes (NRC37: high isoflavone; and NRC7: low isoflavone). Differential expression of MYB65-Gma-miR159, MYB96-Gma-miRNA1534, MYB176-Gma-miRNA5030, SPL9-Gma-miRNA156, TCP3, TCP4-Gma-miRNA319, WD40-Gma-miRNA162, UDP-glucose: flavonoid 3-O-glucosyltransferase-Gma-miRNA396, and CHI3-Gma-miRNA5434 showed an important relationship with their targets in both the soybean genotypes across all the stages. Therefore, the finding of the present work would certainly increase our understanding of molecular regulation of isoflavone biosynthetic pathway mediated by the miRNA which would guide molecular breeder to develop isoflavone rich soybean cultivars.