Abstract
Iron (Fe) is an essential micronutrient that is frequently inaccessible to plants. Rice (Oryza sativa L.) plants employ the Combined Strategy for Fe uptake, which is composed by all features of Strategy II, common to all Poaceae species, and some features of Strategy I, common to non-Poaceae species. To understand the evolution of Fe uptake mechanisms, we analyzed the root transcriptomic response to Fe deficiency in O. sativa and its wild progenitor O. rufipogon. We identified 622 and 2,017 differentially expressed genes in O. sativa and O. rufipogon, respectively. Among the genes up-regulated in both species, we found Fe transporters associated with Strategy I, such as IRT1, IRT2 and NRAMP1; and genes associated with Strategy II, such as YSL15 and IRO2. In order to evaluate the conservation of these Strategies among other Poaceae, we identified the orthologs of these genes in nine species from the Oryza genus, maize and sorghum, and evaluated their expression profile in response to low Fe condition. Our results indicate that the Combined Strategy is not specific to O. sativa as previously proposed, but also present in species of the Oryza genus closely related to domesticated rice, and originated around the same time the AA genome lineage within Oryza diversified. Therefore, adaptation to Fe2+ acquisition via IRT1 in flooded soils precedes O. sativa domestication.
Highlights
Iron (Fe) is an essential micronutrient for virtually all organisms
Our results indicate that the Combined Strategy (CS) observed in rice, based on OsYL15 and OsIRT1 as Fe3+ -phytosiderophore and Fe2+ transporters, is not an evolutionary novelty restricted to O. sativa, but has an origin that precedes the split of most AA genome Oryza species
Shoot length decreased significantly in O. sativa plants compared with plants in CC after seven days of −Fe, while no change was observed in O. rufipogon plants (Fig. 1A)
Summary
Iron (Fe) is an essential micronutrient for virtually all organisms. In humans, anemia prevalence was one third of world population in 2010, and Fe deficiency anemia (IDA) is correlated with decreased cognitive performance, low weight at birth, and child and maternal mortality[1]. The first MA synthesized in the pathway is DMA, but different grass species may secrete other forms of MAs. Phytosiderophore secretion is performed by OsZIFL4/TOM1 (transporter of mugineic acid family phytosiderophores 1) in rice[14,15]. Our results indicate that the CS observed in rice, based on OsYL15 and OsIRT1 as Fe3+ -phytosiderophore and Fe2+ transporters, is not an evolutionary novelty restricted to O. sativa, but has an origin that precedes the split of most AA genome Oryza species. This suggests a common origin for the CS in these species, and indicates that adaptation to Fe2+ acquisition in flooded soils precedes rice domestication
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
