Assessing nutritional and genetic variations within foxtail millet (Setaria italica) landraces collected from indigenous communities across the Philippines

Nelzo C Ereful; Jose Arnel O Reyes; Don Emanuel M Cardona; Roneil Christian S Alonday; Nel Oliver B Mateo; Huw Jones; Lesley Boyd; Evelyn F Delfin

doi:10.1016/j.heliyon.2023.e22964

Assessing nutritional and genetic variations within foxtail millet (Setaria italica) landraces collected from indigenous communities across the Philippines

Heliyon. 2023 Dec 1;9(12):e22964. doi: 10.1016/j.heliyon.2023.e22964. eCollection 2023 Dec.

Authors

Nelzo C Ereful¹, Jose Arnel O Reyes¹, Don Emanuel M Cardona², Roneil Christian S Alonday¹, Nel Oliver B Mateo¹, Huw Jones³, Lesley Boyd³, Evelyn F Delfin¹

Affiliations

¹ Institute of Plant Breeding, College of Agriculture and Food Science, University of the Philippines Los Baños, Laguna, 4031, Philippines.
² Philippine Genome Center for Agriculture, Livestock, Forestry and Fisheries, Office of the Vice Chancellor for Research and Extension, University of the Philippines Los Baños, Laguna 4031 Philippines.
³ National Institute of Agricultural Botany, 93 Lawrence Weaver Road, Cambridge, United Kingdom C3 0LE, UK.

Abstract

Unknown to many, the Philippines is host to a few remaining accessions of the underutilised and understudied cereal foxtail millet (Setaria italica (L.) P. Beauv.). We collected together accessions of this crop from different eco-geographical locations within the Philippines, along with a few accessions from Lanyu, Taiwan, to undertake a study of their nutritional value and genetic diversity. All accessions were field-grown in 2022, dry season (DS) at the Institute of Plant Breeding (IPB) Experiment Station, Los Baños, Laguna, Philippines. The accessions were tested for micronutrients, including Zn and Fe, nitrogen as a proxy for protein, β-carotene, phytic acid, and a number of phenolic compounds with known nutritional potential. Of the 20 accessions tested, the accessions Bayaras and GB61438 had the highest level of Zn (107.1 mg/kg) and Fe (70.52 mg/kg), respectively, higher than levels found in traditional rice varieties. For β-carotene the highest concentration was found in the accession Balles (∼10 μg/g). Twelve phenolic compounds were detected, with catechin, syringic acid, ferulic acid and kaempferol having the highest concentrations. To assess the genetic diversity, we sequenced a set of eight samples selected from among the accessions to a depth of at least 25-fold using whole-genome re-sequencing. Analysis of the population structure, using genome-wide, high-quality SNPs, showed modest diversity among the accessions, with two unadmixed groups. The accessions are monophyletic relative to their earliest common ancestor, with the very light brown accessions emerging earlier than the light brown and reddish-brown varieties. Analysis of zinc-regulated, iron-regulated transporter-like protein (ZIP) transporters within the foxtail millet reference sequence, var. Yugu1 identified 17 putative ZIP transporters. Variant calling identified SNPs primarily within 3' and 5' regions, and introns, indicating variation between foxtail millet accessions within regulatory gene regions rather than in structural proteins. The local foxtail millet accessions, therefore, represent a potential alternative source of nutrients which may help in addressing malnutrition in the Philippines.

Keywords: Foxtail millet; Iron; Nutrient composition; Whole genome re-sequencing; Zinc; β-carotene.