MicroRNAs for understanding and improving agronomic traits in oilseed Brassicas

Oilseed Brassicas are economically important crops, with Brassica napus, B. juncea, and B. rapa constituting prominent oilseed resources in the Indian subcontinent and across the world. Improving of oil yield, quality, and resistance to abiotic and biotic stresses in oilseed Brassicas warrants concerted efforts. Owing to quantitative nature, the genetic basis of these traits is complex, and can be significantly improved by incorporating the knowledge of precise genetic regulation of these traits. MicroRNAs (miRNAs) can act as attractive targets for crop improvement as they fine-tune gene expression by targeting genes negatively. Here we highlight the emerging evidences of miRNA-mediated regulation of genes controlling several development traits and stress-related traits in oilseed Brassicas. At least 13 miRNAs have so far been well elucidated in oilseed Brassicas using miRNA overexpression, mutation and target mimic approaches, in regulation of different agronomic traits. Further, at least 29 high-throughput small RNA profiling studies have proffered crucial miRNA-target pair candidates for further investigation. This knowledge so far remains unutilized in designing crop improvement programs in oilseed Brassicas. However, there are sufficient evidences to suggest that miRNAs as well as their target genes can be successfully employed in breeding as well as genome editing-mediated engineering of oilseed crops for improving their agricultural traits.