Harnessing the Wild Relatives and Landraces for Fe and Zn Biofortification in Wheat through Genetic Interventions—A Review

Abstract

Micronutrient deficiencies, particularly iron (Fe) and zinc (Zn), in human diets are affecting over three billion people globally, especially in developing nations where diet is cereal-based. Wheat is one of several important cereal crops that provide food calories to nearly one-third of the population of the world. However, the bioavailability of Zn and Fe in wheat is inherently low, especially under Zn deficient soils. Although various fortification approaches are available, biofortification, i.e., development of mineral-enriched cultivars, is an efficient and sustainable approach to alleviate malnutrition. There is enormous variability in Fe and Zn in wheat germplasm, especially in wild relatives, but this is not utilized to the full extent. Grain Fe and Zn are quantitatively inherited, but high-heritability and genetic correlation at multiple locations indicate the high stability of Fe and Zn in wheat. In the last decade, pre-breeding activities have explored the potential of wild relatives to develop Fe and Zn rich wheat varieties. Furthermore, recent advances in molecular biology have improved the understanding of the uptake, storage, and bioavailability of Fe and Zn. Various transportation proteins encoding genes like YSL 2, IRT 1, OsNAS 3, VIT 1, and VIT 2 have been identified for Fe and Zn uptake, transfer, and accumulation at different developing stages. Hence, the availability of major genomic regions for Fe and Zn content and genome editing technologies are likely to result in high-yielding Fe and Zn biofortified wheat varieties. This review covers the importance of wheat wild relatives for Fe and Zn biofortification, progress in genomics-assisted breeding, and transgenic breeding for improving Fe and Zn content in wheat.

Multi-Trait Genomic Prediction Models Enhance the Predictive Ability of Grain Trace Elements in Rice

“…Therefore, the genetic architecture of the target traits must be studied before applying this strategy to a breeding program. The marked advantage of the haplotype-based UN model over their genotype-based counterparts using the TA-SNPs ( Figures 7A–C ) substantiates the existence of local epistasis in trace element traits ( Sharma V. et al, 2021 ) and the merit of modelling local epistatic effects in MT-GP program.…”

“…As a genomics-enabled breeding approach, marker-assisted selection (MAS) is useful to improve trace element traits when genes/QTLs with large additive genetic effects exist ( Wu et al, 2020 ). However, prominent non-additive gene action has also been reported for trace element traits, making MAS-based strategies ineffective ( Sharma V. et al, 2021 ). In addition, MAS-based breeding methods are practically ineffective at simultaneously exploiting information from multiple genes ( Spindel et al, 2016 ) or traits ( Van Der Straeten et al, 2020 ).…”

Biofortification of Triticum species: a stepping stone to combat malnutrition

“…This approach is currently underutilized, despite extensive research being conducted using this method [ 189 ]. In genetic engineering, desirable genes can be transferred between plants regardless of their evolutionary or taxonomic relationship, allowing for the production of transgenic crops (Additional file 3; Table S3 ).…”

Biofortification to avoid malnutrition in humans in a changing climate: Enhancing micronutrient bioavailability in seed, tuber, and storage roots

“…Sorghum wild relatives, "Almahkara" and "Abusabiba", respectively, had in the seeds the highest concentrations of total and bioavailable iron, 3.17 mg 100 g −1 and 92.8 mg 100 g −1 , while another wild sorghum "Adar Umbatikh" grain had a higher zinc content (Abdelhalim et al, 2019). Einkorn (T. monococcum) wheat, the wild emmer (T. dicoccoides), diploid progenitors of hexaploid wheat (Aegilops tauschii), T. spelta, T. polonicum, and wheat landraces are the most promising sources of seed Fe and Zn (Cakmak et al, 2004;Chhuneja et al, 2006;Sharma V. et al, 2021). Resynthesized hexaploid wheat originating from crosses between T. durum or T. dicoccum and diverse sources of Ae.…”

“…Einkorn ( T. monococcum ) wheat, the wild emmer ( T. dicoccoides ), diploid progenitors of hexaploid wheat ( Aegilops tauschii ), T. spelta , T. polonicum , and wheat landraces are the most promising sources of seed Fe and Zn ( Cakmak et al., 2004 ; Chhuneja et al., 2006 ; Sharma V. et al., 2021 ). Resynthesized hexaploid wheat originating from crosses between T. durum or T. dicoccum and diverse sources of Ae.…”