Identification of Aegilops species with higher production of phytosiderophore and iron and zinc uptake under micronutrient-sufficient and -deficient conditions

Graminaceous plants including staple cereals secrete certain phytosiderophores (PS) in calcareous soils with lower iron and zinc availability to enhance their uptake and translocation to the leaves and grains. A few Triticum aestivum cultivars and accessions of six Aegilops species were investigated for release of PS in vitro under iron- and zinc-sufficient and –deficient conditions, and for root and shoot iron and zinc concentrations. All the Aegilops species had three to four times higher release of PS than the wheat cultivars under both nutrient-sufficient and -deficient conditions. The maximum rate of increase of PS was observed on days 11 and 14 under iron- and zinc-deficient conditions, respectively, which levelled off rapidly among the wheat cultivars and continued to be high among Aegilops species till the end of the experiment. The absolute amount of iron and zinc expressed on dry weight basis after 18 d under iron- and zinc-deficient conditions showed nearly three times higher concentration in both roots and shoots of Aegilops species than that of the wheat cultivars. A significantly high correlation between concentrations of iron (r ¼ 0.94) and zinc (r ¼ 0.91) in roots and the PS released was found. The higher grain iron and zinc contents in the Aegilops species reported earlier may be attributed to their diverse and efficient mechanism(s) for PS-mediated micronutrient uptake and translocation system, which could be exploited for biofortification of wheat.