Genome-Wide Association Mapping of Grain Micronutrients Concentration in Aegilops tauschii

Abstract

Bread wheat is an important and the most consumed cereal worldwide. However, people with predominantly cereal-based diets are increasingly affected by micronutrient deficiencies, suggesting the need for biofortified wheat varieties. The limited genetic diversity in hexaploid wheat warrants exploring the wider variation present in wheat wild relatives, among these Aegilops tauschii, the wild progenitor of the bread wheat D genome. In this study, a panel of 167 Ae. tauschii accessions was phenotyped for grain Fe, Zn, Cu, and Mn concentrations for 3 years and was found to have wide variation for these micronutrients. Comparisons between the two genetic subpopulations of Ae. tauschii revealed that lineage 2 had higher mean values for Fe and Cu concentration than lineage 1. To identify potentially new genetic sources for improving grain micronutrient concentration, we performed a genome-wide association study (GWAS) on 114 non-redundant Ae. tauschii accessions using 5,249 genotyping-by-sequencing (GBS) markers. Best linear unbiased predictor (BLUP) values were calculated for all traits across the three growing seasons. A total of 19 SNP marker trait associations (MTAs) were detected for all traits after applying Bonferroni corrected threshold of -log10(P-value) ≥ 4.68. These MTAs were found on all seven chromosomes. For grain Fe, Zn, Cu, and Mn concentrations, five, four, three, and seven significant associations were detected, respectively. The associations were linked to the genes encoding transcription factor regulators, transporters, and phytosiderophore synthesis. The results demonstrate the utility of GWAS for understanding the genetic architecture of micronutrient accumulation in Ae. tauschii, and further efforts to validate these loci will aid in using them to diversify the D-genome of hexaploid wheat.

Evaluation of Triticum durum–Aegilops tauschii derived primary synthetics as potential sources of heat stress tolerance for wheat improvement

“…However, a negative correlation between GL and GB was reported by Arora et al . (2019) in wheat and Agrama et al . (2007) in rice.…”

“…Punjab Agricultural University, Ludhiana, India has been maintaining and evaluating a collection of Ae. tauschii accessions for various biotic stress, abiotic stress and different agronomic traits (Chhuneja et al ., 2006, 2008, 2010; Gupta et al ., 2010; Arora et al ., 2019). Several SHW lines between Triticum durum Desf.…”

Marker-assisted pyramiding of lycopene-ε-cyclase, β-carotene hydroxylase1 and opaque2 genes for development of biofortified maize hybrids

“…For each entry the grains were divided into three parts and analyzed as three replicates for estimation of different mineral nutrients viz . , Fe, Zn, Cu, Se, Mn, S, K, P, and Mg using simultaneous multi-element inductively coupled plasma–optical emission spectrometer (ICP-OES, Perkin Elmer) as per the methodology described by Arora et al 57 . The value obtained was then multiplied by initial sample volume, divided by initial weight of grains, and expressed as μg element g −1 dry grain material (ppm) 58 .…”

Genetic Control of Iron Bioavailability is Independent from Iron Concentration in a Diverse Winter Wheat Mapping Population

“…However, we successfully identified four QTL explaining around 30% of the genetic variation of Fe concentration in total in year 1, and these differed from the single QTL found in year 2, with the QTL profiles between years being noticeably different (Figure 3). Therefore, we conclude that there is a high level of Genotype x Environment (GxE) interaction for Fe levels in the grain, which may have had an impact on the success of breeding for increased Fe concentration [11,39,41,46,47], despite the evidence of underlying QTL variation in a number of important cereal species [11,16,41,46,48,49]. However, it should be noted that the power analyses (Suppl.…”