Ferric-chelate reductase OsFRO1 involved in Fe reduction and long distance Fe transport channelized by OsYSL2 and OsYSL15 in rice

Abstract

Abstract Iron (Fe) is essential micronutrient that controls dynamic functions within cell of plants and its homeostasis is crucial for plant growth. In the present study, we found that a rice FRO gene, OsFRO1, dominantly expressed in young panicles and seedling. It is specifically responsible for Fe treatment and localized in the plasma membrane of cells. OsFRO1 positively interacts with two Fe transporters, Yellow Stripe-Like protein 2 (OsYSL2) and 15 (OsYSL15), which are further involved in long distance Fe transport. Knockdown of OsFRO1 (RNAi) suppressed the expression of the gene in Fe stress and substantially affected plant physiology and morphology with reduced Fe concentration in root and shoot of rice under Fe toxicity. Over-expression of OsFRO1 (OE) showed up-regulation and excess Fe excess increased ROS generation and plant senescence. In addition, the RNAi lines showed lower expression levels of OsYSL2 and OsYSL15 with less Fe toxicity and maintained greenness, modulated antioxidant activity compared to WT, whereas, the OE showed high transcript levels of the two gene and more Fe toxicity. All these results suggest that OsFRO1 functions in both Fe-reduction and Fe-uptake or translocation channelized by OsYSL2 and OsYSL15 transporters and plays crucial roles in Fe homeostasis in rice.