An Al-inducible MATE gene is involved in external detoxification of Al in rice
Article first published online: 10 OCT 2011
© 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd
The Plant Journal
Volume 68, Issue 6, pages 1061–1069, December 2011
How to Cite
Yokosho, K., Yamaji, N. and Ma, J. F. (2011), An Al-inducible MATE gene is involved in external detoxification of Al in rice. The Plant Journal, 68: 1061–1069. doi: 10.1111/j.1365-313X.2011.04757.x
- Issue published online: 13 DEC 2011
- Article first published online: 10 OCT 2011
- Accepted manuscript online: 22 AUG 2011 03:52PM EST
- Received 29 June 2011; revised 12 August 2011; accepted 19 August 2011; published online 10 October 2011.
- aluminum tolerance;
- multidrug and toxic compound excursion;
A number of plant species, including rice, secretes citrate from roots in response to Al stress. Here we characterized the functions of a gene, OsFRDL4 (Os01g0919100) that belongs to the multidrug and toxic compound extrusion (MATE) family in rice (Oryza sativa). Heterologous expression in Xenopus oocyte showed that the OsFRDL4 protein was able to transport citrate and was activated by Al. The expression level of the OsFRDL4 gene in roots was very low in the absence of Al, but was greatly enhanced by Al after short exposure. Furthermore, the OsFRDL4 expression was regulated by ART1, a C2H2-type zinc finger transcription factor for Al tolerance. Transient expression of OsFRDL4 in onion epidermal cells showed that it localized to the plasma membrane. Immunostaining showed that OsFRDL4 was localized in all cells in the root tip. These expression patterns and cell specificity of localization of OsFRDL4 are different from other MATE members identified previously. Knockout of OsFRDL4 resulted in decreased Al tolerance and decreased citrate secretion compared with the wild-type rice, but did not affect citrate concentration in the xylem sap. Furthermore, there is a positive correlation between OsFRDL4 expression level and the amount of citrate secretion in rice cultivars that are differing in Al tolerance. Taken together, our results show that OsFRDL4 is an Al-induced citrate transporter localized at the plasma membrane of rice root cells and is one of the components of high Al tolerance in rice.