Researchers identified the molecular basis of soybean seed coat color

Gene silencing is the process by which the activity of the genes is regulated so that a particular gene's expression can be prevented.

- Priyanka Kumari, Anshul watts

Small non-coding RNAs such as micro-RNA (22 nucleotide length) and small interfering RNA (siRNA; 21-24 nucleotide length) suppress the gene expression by degradation of corresponding messenger RNA (mRNA) molecules. These small RNAs can be produced either endogenously or exogenously provided to the cell. These small RNAs are processed by Dicer-like enzyme (DCL) and then RNA-induced silencing complex (RISC) assembly is formed with the help of argonaute (AGO) protein. Further, they target their complementary mRNAs and then either silence its expression by partial (by miRNA) or complete degradation the target mRNA (by siRNA). It has also been reported that siRNA also leads to the production of secondary siRNA, which are 21 nucleotides (nt) in length. These secondary siRNAs further amplify the silencing process. SiRNAs which are of 22 nt length, is processed by DCL2 while 24 and 21 nt siRNA are processed by DCL3 and DCL4 enzymes respectively. Various functions have been assigned for 21 and 24 nt siRNAs; however, much has not been known about 22 nt siRNAs. Recently these 22 nt siRNA have been identified in various functions such as environmental stress and nutrient deficiency (Wu et al. 2020).

Seed coat color in soybean