The ratio of phytosiderophores nicotianamine to deoxymugenic acid controls metal homeostasis in rice
The ratio of nicotianamine to deoxymugenic acid controls tissue-specific metal homeostasis in rice and regulates metal delivery to the endosperm.
The metal-chelating phytosiderophores nicotianamine (NA) and 2′deoxymugenic acid (DMA) are significant factors for the control of metal homeostasis in graminaceous plants. These compounds are thought to influence metal homeostasis, but their individual roles and the effect of altering the NA:DMA ratio are unknown. We purposely generated rice lines with high and low NA:DMA ratios (HND and LND lines, respectively). The HND lines accumulated more iron (Fe), zinc (Zn), manganese (Mn) and copper (Cu) in the endosperm through the mobilization of Fe, Zn and Mn from the seed husk to the endosperm. In contrast, Fe, Zn and Mn were mobilized to the husk in the LND lines, whereas Cu accumulated in the endosperm. Different groups of metals are, therefore, taken up, transported and sequestered in vegetative tissues in the HND and LND lines to achieve this metal distribution pattern in the seeds. We found that different sets of endogenous metal homeostasis genes were modulated in the HND and LND lines to achieve differences in metal homeostasis. Our findings demonstrate that the NA:DMA ratio is a key factor regulating metal homeostasis in graminaceous plants. These findings can help formulate refined strategies to improve nutrient composition and nutrient use efficiency in crop plants.
KeywordsMetal homeostasis NA:DMA ratio Oryza sativa L. Phytosiderophores Transcriptome
We acknowledge support from the European Research Council IDEAS Advanced Grant Program (BIOFORCE) to P.C., Generalitat de Catalunya Grant 2017 SGR 828 to ABBU (BIO2014-54426-P) and the Spanish Ministry of Economy and Competitivity (MINECO; projects AGL2016-75226-R, co-financed with FEDER) and the Aragón Government (Group A09_17R) to J.A. R.B was supported by a PhD fellowship from the University of Lleida, Spain.
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Conflict of interest
The authors declare that they have no conflict of interest.
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