期刊
NEW PHYTOLOGIST
卷 195, 期 2, 页码 356-371出版社
WILEY
DOI: 10.1111/j.1469-8137.2012.04167.x
关键词
Arabidopsis thaliana; arsenate toxicity; phosphate starvation; phosphate transporter; plasma membrane; root branching; Saccharomyces cerevisiae
资金
- Fundacao para a Ciencia e a Tecnologia [PTDC/AGR-AAM/67858/2006, PTDC/AGR-AAM/102967/2008, SFRH/BPD/44640/2008, SFRH/BPD/81221/2011]
- Programa Ciencia (QREN/MCTES)
- Fundação para a Ciência e a Tecnologia [PTDC/AGR-AAM/102967/2008, SFRH/BPD/44640/2008, PTDC/AGR-AAM/67858/2006] Funding Source: FCT
The activation of high-affinity root transport systems is the best-conserved strategy employed by plants to cope with low inorganic phosphate (Pi) availability, a role traditionally assigned to Pi transporters of the Pht1 family, whose respective contributions to Pi acquisition remain unclear. To characterize the Arabidopsis thaliana Pht1;9 transporter, we combined heterologous functional expression in yeast with expression/subcellular localization studies and reverse genetics approaches in planta. Double Pht1;9/Pht1;8 silencing lines were also generated to gain insight into the role of the closest Pht1;9 homolog. Pht1;9 encodes a functional plasma membrane-localized transporter that mediates high-affinity Pi/H+ symport activity in yeast and is highly induced in Pi-starved Arabidopsis roots. Null pht1;9 alleles exhibit exacerbated responses to prolonged Pi limitation and enhanced tolerance to arsenate exposure, whereas Pht1;9 overexpression induces the opposite phenotypes. Strikingly, Pht1;9/Pht1;8 silencing lines display more pronounced defects than the pht1;9 mutants. Pi and arsenic plant content analyses confirmed a role of Pht1;9 in Pi acquisition during Pi starvation and arsenate uptake at the rootsoil interface. Although not affecting plant internal Pi repartition, Pht1;9 activity influences the overall Arabidopsis Pi status. Finally, our results indicate that both the Pht1;9 and Pht1;8 transporters function in sustaining plant Pi supply on environmental Pi depletion.
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