Harnessing finger millet to combat calcium deficiency in humans: challenges and prospects

Puranik S, Kam J, Sahu PP, Yadav R, Srivastava RK, Ojulong H and Yadav R (2017) Harnessing Finger Millet to Combat Calcium Deficiency in Humans: Challenges and Prospects. Front. Plant Sci. 8:1311. doi: 10.3389/fpls.2017.01311Humans require more than twenty mineral elements for healthy body function. Calcium (Ca), one of the essential macromineral, is required in relatively large quantities in the diet for maintaining a sound overall health. Young children, pregnant and nursing women in marginalized and poorest regions of the world, are at highest risk of Ca malnutrition. Elderly population is another group of people most commonly affected by Ca deficiency mainly in the form of osteoporosis and osteopenia. Improved dietary intake of Ca may be the most cost-effective way to meet such deficiencies. Finger millet [Eleusine coracana (L.) Gaertn.], a crop with inherently higher Ca content in its grain, is an excellent candidate for understanding genetic mechanisms associated with Ca accumulation in grain crops. Such knowledge will also contribute towards increasing Ca contents in other staple crops consumed on daily basis using plant-breeding (also known as biofortification) methods. However, developing Ca-biofortified finger millet to reach nutritional acceptability faces various challenges. These include identifying and translating the high grain Ca content to an adequately bioavailable form so as to have a positive impact on Ca malnutrition. In this review, we assess some recent advancements and challenges for enrichment of its Ca value and present possible inter-disciplinary prospects for advancing the actual impact of Ca-biofortified finger millet.publishersversionPeer reviewe

Genomic and phenotypic characterization of finger millet indicates a complex diversification history

Advances in sequencing technologies mean that insights into crop diversification can now be explored in crops beyond major staples. We use a genome assembly of finger millet, an allotetraploid orphan crop, to analyze DArTseq single nucleotide polymorphisms (SNPs) at the whole and sub‐genome level. A set of 8778 SNPs and 13 agronomic traits was used to characterize a diverse panel of 423 landraces from Africa and Asia. Through principal component analysis (PCA) and discriminant analysis of principal components, four distinct groups of accessions were identified that coincided with the primary geographic regions of finger millet cultivation. Notably, East Africa, presumed to be the crop's origin, exhibited the lowest genetic diversity. The PCA of phenotypic data also revealed geographic differentiation, albeit with differing relationships among geographic areas than indicated with genomic data. Further exploration of the sub‐genomes A and B using neighbor‐joining trees revealed distinct features that provide supporting evidence for the complex evolutionary history of finger millet. Although genome‐wide association study found only a limited number of significant marker‐trait associations, a clustering approach based on the distribution of marker effects obtained from a ridge regression genomic model was employed to investigate trait complexity. This analysis uncovered two distinct clusters. Overall, the findings suggest that finger millet has undergone complex and context‐specific diversification, indicative of a lengthy domestication history. These analyses provide insights for the future development of finger millet

Genome-wide association study reveals the genetic architecture of grain calcium accumulation in finger millet

Calcium (Ca) is an essential macromineral and required in relatively large dietary quantities for maintaining a sound overall health. Therefore, significant progress is needed for biofortification of staple crops to enhance grain Ca content. Among all cultivated cereals, finger millet [Eleusine coracana (L.) Gaertn.], has the highest concentration of Ca (350mg/100g) in its grains and can serve as an excellent sustainable candidate for Ca biofortification. With the aim to identify genomic loci underlying grain Ca content, we performed genome-wide association (GWA) analysis utilizing a world collection of finger millet germplasm. Grain Ca contents showed very high variability among the collection with distinct differences observed among African, Asian, European and American genotypes. Large-scale genotyping-by sequencing was employed and 154238 bialleleic, polymorphic SNPs with a MAF ? 1 % across the genotypes were employed for GWA mapping. Associations were done by fitting three statistical models. After correction for population structure and family relatedness, loci showing strong associations with grain Ca content have been identified. This is the first GWA study based on large-scale SNP genotyping in finger millet for grain Ca content. The novel genomic loci identified can facilitate positional cloning of underlying causal genes. These results will facilitate further improvement of finger millet and also other staple crops. Such crops will be a tremendous boost for smallholder farmers, agriculture sectors, and food industries which will help to reduce the burden of Ca deficiency.Non peer reviewe