Harnessing the Transcriptomic Resources of Millets to Decipher Climate Resilience and Nutrient Enrichment Traits

Abstract

Rich nutrients, climate resilience, and the economic importance of millets are believed to ensure food security for future generations. Millets have the habit of growing against abiotic stresses (particularly drought stress). Millets show much better climate resilience and nutrient supplementation properties compared to other major cereals. Understanding the molecular mechanisms of genes that respond to stresses and nutrient transport will help understand the tolerance mechanism and improve against both stresses. Genome sequences are currently available for two major (sorghum and pearl millet) and eight minor millets (foxtail millet, finger millet, kodo millet, barnyard millet, proso millet, job’s tear, fonio millet, and tef). Five minor millets (little millet, kodo millet, brown top millet, guinea millet, and raishan) do not have genome sequences to date. Transcriptome studies help to identify differentially expressed genes (DEGs), mine genes induced in a particular stress and develop several molecular markers for all plants, including millets. Some millets have reports on transcriptome datasets for plants exposed to various biotic and abiotic stresses and for nutritional traits. Unfortunately, the transcriptome datasets of millets have not been adequately leveraged to explore genes associated with traits such as climate resilience, nutrient enrichment, and crop improvement. This underutilization stems from a lack of high-resolution studies and limited exploration within the field. As a result, the potential insights and genetic understanding offered by these datasets remain largely untapped. Through this review, we plan to elucidate the current status of transcriptome resources on millets and draw future insights on the utilization of these resources. This review will motivate researchers to utilize the available transcriptome resources for millet improvement.