MicroRNA-mediated regulation of agronomically important seed traits: a treasure trove with shades of grey!

Abstract

Seed development is an intricate process with multiple levels of regulation. MicroRNAs (miRNAs) have emerged as one of the crucial components of molecular networks underlying agronomically important seed traits in diverse plant species. In fact, loss of function of the genes regulating miRNA biogenesis also exhibits defects in seed development. A total of 21 different miRNAs have experimentally been shown to regulate seed size, nutritional content, vigor, and shattering, and have been reviewed here. The mechanism details of the associated regulatory cascades mediated through transcriptional regulators, phytohormones, basic metabolic machinery, and secondary siRNAs are elaborated. Co-localization of miRNAs and their target regions with seed-related QTLs provides new avenues for engineering these traits using conventional breeding programs or biotechnological interventions. While global analysis of miRNAs using small RNA sequencing studies are expanding the repertoire of candidate miRNAs, recent revelations on their inheritance, transport, and mechanism of action would be instrumental in designing better strategies for optimizing agronomically relevant seed traits.

Keywords:

• microRNA
• seed
• seed quality
• seed size
• seed shattering
• seed vigor
• seed development

Acknowledgments

The authors thank Dr Ira Vashisht and Ms Rashmi Maurya for their useful comments.

Disclosure statement

The authors declare that they have no conflicts of interest.

Additional information

Funding

N. D. acknowledges financial assistance from the Department of Science and Technology (DST), Government of India as DST-INSPIRE Faculty award [DST/INSPIRE/04/2017/002597]. R. S. acknowledges the support from grant number BT/BI/03/004/2003(C) of the Government of India, Ministry of Science and Technology, Department of Biotechnology, Bioinformatics division and research grant from Science and Engineering Research Board (SERB), Department of Science and Technology (DST), Government of India [ECR/2016/001581].