AtPDR9 and NtPDR3, two homologous pleiotropic drug resistance transporters, are involved in the plant response to iron deficiency
(2010)
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- Authors
- Supervisors
- Boutry, Marc
- Abstract
- (en) Iron is an essential micronutrient for virtually all living organisms. This work deals with the functional characterization of AtPDR9 and NtPDR3, two homologous plant ABC (ATP-binding cassette) transporters involved in the response to iron deficiency, from Arabidopsis and Nicotiana tabacum, respectively. ABC transporters mediate the ATP-dependent translocation of a wide range of structurally and functionally unrelated compounds across biological membranes. AtPDR9 and NtPDR3 expression was found to be induced by iron deficiency and both proteins appeared to localize to the plasma membrane of the root epidermal cells. The characterization of Arabidopsis and N. tabacum mutant plants that do not express AtPDR9 or NtPDR3 revealed that the mutant plants were less tolerant to iron-deficient conditions than wild type plants, displaying a stronger chlorosis and growth retardation when not supplied with iron. Phenolic compounds are known to be abundant in the iron-deficient plant root exudate. Interestingly, exogenous application of certain phenolics was shown to rescue the mutant plants phenotype on iron-depleted medium. Moreover, phenolics were shown to accumulate in the roots of iron-deficient mutant plants. These data provide strong evidence supporting phenolic compounds as putative substrates of AtPDR9 and NtPDR3. Finally, the obtaining of tools aiming at demonstrating the transport properties of AtPDR9 and NtPDR3 was undertaken. NtPDR3 was successfully expressed in N. tabacum BY2 cells. Transport assays demonstrated that this material is appropriate for testing putative substrates of PDR proteins. Altogether, the data obtained in this work indicate that AtPDR9 and NtPDR3 transport phenolics to the rhizosphere under low iron supply, a mechanism that appears to be critical for plant tolerance to iron deficiency.
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Citations
Fourmeau, J. (2010). AtPDR9 and NtPDR3, two homologous pleiotropic drug resistance transporters, are involved in the plant response to iron deficiency. https://hdl.handle.net/2078.5/65861