Genome-wide association study uncovers genomic regions associated with grain iron, zinc and protein content in pearl millet

Sci Rep. 2020 Nov 10;10(1):19473. doi: 10.1038/s41598-020-76230-y.

Abstract

Pearl millet hybrids biofortified with iron (Fe) and zinc (Zn) promise to be part of a long-term strategy to combat micronutrient malnutrition in the arid and semi-arid tropical (SAT) regions of the world. Biofortification through molecular breeding is the way forward to achieving a rapid trait-based breeding strategy. This genome-wide association study (GWAS) was conducted to identify significant marker-trait associations (MTAs) for Fe, Zn, and protein content (PC) for enhanced biofortification breeding. A diverse panel of 281 advanced inbred lines was evaluated for Fe, Zn, and PC over two seasons. Phenotypic evaluation revealed high variability (Fe: 32-120 mg kg-1, Zn: 19-87 mg kg-1, PC: 8-16%), heritability (hbs2 ≥ 90%) and significantly positive correlation among Fe, Zn and PC (P = 0.01), implying concurrent improvement. Based on the Diversity Arrays Technology (DArT) seq assay, 58,719 highly informative SNPs were filtered for association mapping. Population structure analysis showed six major genetic groups (K = 6). A total of 78 MTAs were identified, of which 18 were associated with Fe, 43 with Zn, and 17 with PC. Four SNPs viz., Pgl04_64673688, Pgl05_135500493, Pgl05_144482656, and Pgl07_101483782 located on chromosomes Pgl04 (1), Pgl05 (2) and Pgl07 (1), respectively were co-segregated for Fe and Zn. Promising genes, 'Late embryogenesis abundant protein', 'Myb domain', 'pentatricopeptide repeat', and 'iron ion binding' coded by 8 SNPs were identified. The SNPs/genes identified in the present study presents prospects for genomics assisted biofortification breeding in pearl millet.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Chromosome Mapping / methods
  • Chromosomes, Plant / genetics
  • Edible Grain / genetics*
  • Edible Grain / metabolism
  • Genome, Plant / genetics*
  • Genome-Wide Association Study / methods*
  • Genomics / methods
  • Genotype
  • Iron / metabolism*
  • Linkage Disequilibrium
  • Models, Genetic
  • Pennisetum / classification
  • Pennisetum / genetics*
  • Pennisetum / metabolism
  • Plant Breeding / methods
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Polymorphism, Single Nucleotide
  • Zinc / metabolism*

Substances

  • Plant Proteins
  • Iron
  • Zinc