18th International Symposium on Iron Nutrition and Interaction in Plants
Madrid – May 30-June 3 2016
OVEREXPRESSION OF THE COPPER TRANSPORTER ATCOPT1 INCREASES IRON
CONTENT IN RICE GRAINS
Amparo Andrés-Bordería*, Fernando Andrés, Antoni Garcia-Molina, Ana Perea-García, Concha
Domingo, Sergi Puig and Lola Peñarrubia.
*[email protected] Departamento de Bioquímica y Biología Molecular, Universidad de Valencia. Burjassot,
Valencia, Spain.
Iron (Fe) deficiency, leading to anemia, is a widespread health problem that affects more than two billion
people. Fe supplementation and biofortification are identified among the top five cost-effective solutions to
global challenges by the international community. Multiple interventions have been encouraged to reduce
micronutrient malnutrition, being the genetic engineering based biofortification one of the most effective.
Since rice (Oryza sativa, L.) is one of the most worldwide consumed crops, and anemia susceptible poor
populations often depend primarily on rice grain as staple food, biofortification strategies for increased Fe
transport and increased delivery to rice grains have been prioritized as a suitable approach to provide Fe to
these populations. Iron and copper homeostases are tightly regulated since both metals are essential for the
plants but toxic when in excess due to their redox properties.
In the present work, we have studied the effects on iron homeostasis of the presence of a wide copper
range in the growth media of Oryza sativa plants. We conducted a global analysis of gene expression in rice
seedlings grown under copper deficiency vs copper excess in the medium. In addition, we have generated
rice transgenic plants that overexpress the Arabidopsis thaliana Cu transporter, AtCOPT1. The global
analysis of gene expression showed an increased expression of genes involved iron homeostasis, both
under copper deficiency and excess, such as those encoding ferredoxin and the transcriptional regulator
IRO2, respectively. As expected, the expression of the high affinity copper transport protein COPT1 was
upregulated under copper deficiency and IRO2 targets expression increased under copper excess.
Furthermore, overexpression of Arabidopsis COPT1 (AtCOPT1OE) in rice causes root shortening under
copper excess, like in Arabidopsis thaliana (Andres-Colás et al, 2010) and increased expression of IRO2 and
its targets, suggesting a role of copper in iron signaling.
Moreover, the effects of the double copper and iron deficiencies have been studied in these AtCOPT1OE
plants, indicating that they are more sensitive than controls to root growth inhibition, suggesting that there is
a relationship between the two metals, as already described for Arabidopsis (Perea-García et al, 2013).
Interestingly, when grown under normal soil cultivation, AtCOPT1OE rice plants contain higher endogenous
iron content in grains than wild type plants, both in brown and polished grains. Taken together, the results
obtained in this study show the interaction between the homeostatic networks of iron and copper, and
suggest new strategies to obtain crops with optimized nutrient content in edible parts.
Keywords: Oryza sativa, copper homeostasis, COPT1, iron, gene expression
Andrés-Colás et al. (2010). Plant Physiol, vol 153: Page 170-184.
Perea-García et al. (2013). Plant Physiol, vol 162: Page 180-194.
This work has been funded by the Spanish Ministry of Economy and Competitiveness (BIO2011-24848)
(BIO2014-56298-P) and by Autonomic government of Comunitat Valenciana (Aico2015/004)
Preferred Presentation format: POSTER.
Selected Sessions: (please, indicate the name of the session from these):
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Molecular regulation of Fe homeostasis
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