Chlorophyll biosynthesis as the basis of iron use efficiency under iron deficiency and its relationship with the phytosiderophore synthesis and release in wheat

Abstract

The present study demonstrates that chlorophyll biosynthesis can be effectively used for identifying iron (Fe) deficiency tolerant cultivars from a large population. Fifty genetically diverse wheat cultivars were screened on the basis of the leaf greenness index, i.e. chlorophyll retention under iron deficient (Fe−) compared to iron sufficient (Fe+) conditions, and three Fe deficiency tolerant and two Fe deficiency susceptible cultivars were identified. These two groups of cultivars were further tested for their efficiency for Fe uptake and translocation and biomass production per unit Fe under Fe deficient condition in the nutrient solution culture. Fe deficiency tolerant lines were found capable of translocating more Fe to the shoot and produced greater biomass per unit of Fe when compared with the susceptible group. Efficiency for chlorophyll biosynthesis per unit shoot Fe was also higher for the tolerant group of cultivars. Fe use efficient cultivars produced and released a larger amount of phytosiderophore (PS) and differed from the inefficient cultivars in terms of the PS release but not in the PS biosynthesis. Thus, indicating that the limitation at the level of release of the PS was responsible for low Fe use efficiency of the Fe deficiency susceptible cultivars. Further the diurnal variation in the PS release was similar for all the investigated wheat cultivars and did not influence the genotypic variation in the Fe use efficiency.