Success to iron biofortification of wheat grain by combining both plant and microbial genetics

Abstract

Iron biofortification of crops, like wheat, is an attractive strategy to cope with iron deficiency causing hidden hunger. Several recent studies dissected the genetics controlling iron concentrations in wheat grain, and expanded our understanding of iron accumulation in wheat grains. However, successful breeding of iron-rich wheat cultivar is limited based on plant genetics. Along with the wide appreciation of wheat-associated microbes, it is evidenced that microbes have a significant effect on iron concentration in grain and impacted plant genetics. These microbes, together called the plant microbiome, lived in either the rhizosphere (rhizobacteria) or the inner tissues of wheat (endophytes). They have complex genetics and influenced iron uptake, remobilization, accumulation and bioavailability, thereby either direct or indirectly contributed to grain iron biofortification in wheat. Although in rice it has been possible to exceed (60–140 μg Fe/g rice grain) the targeted iron biofortification requirement of 59 μg Fe/g cereal grain, most wheat lines only reach 20–40 μg Fe/g wheat grain. In our opinion, it is necessary to combine both plant and microbial genetics for successful iron biofortification in wheat. Application of microbes, especially engineered endophytes incorporated with plant genes controlling iron accumulation may be an efficient and feasible routine for iron biofortification in wheat.