Root Iron Localization and Proteomic Impairment in Anaerobic Rice Cultivars Exposed to Excess Iron

Abstract

Plant faces iron (Fe) toxicity when the concentration of this mineral is high in soils under anaerobic conditions. Excess soil Fe2+may cause severe impairment in rice photosynthe­sis, morphological parameters, and may induce oxidative damage with significant alteration in protein profiles. Present study aimed to investigate the extension of oxidative stress on exposure to excess Fe2+ ion and its effects on the rate of photosynthesis and modifications in protein profiles of rice cultivars with differential sensitivity. A pot experiment was conducted with three Sali rice cultivars, one conventional tolerant cultivar Mahsuri and two iron sensitive varieties Siyal Sali and Ranjit. Constant waterlog environment with four different Fe2+ doses +100 ppm, +200 ppm and +300 ppm treatments and a control without external Fe, were executed. Mahsuri displayed well adaptation to iron overload recording superior morphological parameters with better photosynthetic activity compared to Fe intolerant varieties. The SDS-PAGE results of leaf protein showed that Mahsuri had greater numbers of intense bands indicating more leaf proteins accumulation in all treatments. In contrast Ranjit and Siyal Sali expressed only few weak bands when supplemented with higher Fe2+ doses. Thus proteomic comparison between tolerant and sensitive cultivars after iron overload provides insight into the transcriptional regulation of the variety to tolerance response. These findings establish the foundations of introducing iron tolerance into farmers’ friendly rice cultivars triggering better nutritional values.