Uptake, distribution, and remobilization of iron and zinc among various tissues of wheat-Aegilops substitution lines at different growth stages

Biofortification of wheat for higher grain iron and zinc is the most feasible and cost-effective approach for alleviating micronutrient deficiency. The non-progenitor donor Aegilops species had 2-3 times higher grain iron and zinc content than the wheat cultivars, whereas the wheat-Aegilops substitution lines mostly of group 2 and 7 chromosomes had intermediate levels of grain micronutrients. The non-progenitor Aegilops species also had the highest iron content and intermediate-to-highest zinc content in straw, lower leaves, and flag leaves at the pre-anthesis, grain-filling, and maturity growth stages. The micronutrients accumulation status is followed by wheat-Aegilops substitution lines and is the least in wheat cultivars indicating that the donor Aegilops species and their substituted chromosomes possess genes for higher iron and zinc uptake and mobilization. The grain iron content was highly positively correlated with iron content in the plant tissues. Most of the lines had much higher iron and zinc content in all tissues during grain-filling period indicating higher iron and zinc uptake from soil during this stage. Although iron and zinc contents are nearly similar in grains, there was much less zinc content in the plant tissues of all the lines suggesting that the Triticeae species take up less zinc which is mobilized to grains more effectively than iron.