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OsA8 encodes a typical P-type ATPase-like protein of rice.

Annotated Information


Comparison of the Osa8 mutant and wild-type seedlings grown under phosphate starvation for 2 weeks. (from reference [1]).

As a primary transporter, P-type H+-ATPases (P3A) mediate ATP-dependent H+ extrusion to the extracellular space, a process that generates pH and electrical potential difference across the PM [2][3], and this difference works as the motive force for a large set of secondary transporters, including symporter, antiporter, or uniporter, to drive their substrates against their concentration gradients. [4][5][6] Therefore, the H+-ATPase acts as a transducer: converting the chemical energy released from ATP hydrolysis into chemiosmotic energy. [2] The basic function of P-type H+-ATPases is the coupling ATP hydrolysis and H+-pumping. In general, the cells undergoing active metabolism have much higher activity of H+-ATPase than others. [4][2][7]


Relative expressional level of the OsA8 gene in roots and leaves of wild-type rice grown under different nutrient conditions examined by real-time RT-PCR. (from reference [1]).

Expression pattern of OsA8 is investigated in rice seedlings. Transcripts of OsA8 accumulated more abundantly in roots than in leaves under normal growing condition. OsA8 expression is suppressed in both roots and leaves under N, P, and K deficiency, indicating a much broader role of it in nutrient acquisition in rice. [1]


Schematic representation of the OsA8 gene and the site of Tos17 insertion. (from reference [1]).

Sequencing of the PCR products confirmed a single insertion of Tos17 in the OsA8 gene. Apart from this insertion, no other copies of Tos17 in the mutant were different from wild-type plants. Morphological comparison of the mutant and wild-type rice showed that, regardless of P supply, Osa8 mutants, in general, had smaller leaves, roots, and tillers. Consistent with these differences, biomass of both roots and shoots of the mutant plants is significantly smaller than that of wild-type plants. Notably, the biomass ratio of the root to the shoot in the mutant is significantly lower than that in the wild-type seedlings grown under P-starvation conditions. [1]


According to a previous classification, [8][9] OsA8 belongs to the P3A (AHA) branch, a subgroup of the P-type ATPase family that is specific to plants.

Knowledge Extension

Among 10 OsA genes in rice, expression of OsA5, OsA9, and OsA10 is not detectable. Expression of OsA3 and OsA7 is relatively higher in both the OsA8 mutant and the wild-type seedlings. Knockout of OsA8 increased the expression of OsA1 and OsA2 in the roots of Pi-starved mutants. However, a lower abundance of OsA2 is noticed in leaves of the mutant. In addition, OsA6 appears to be induced only in roots of Pi-sufficient wild-type plant. OsA4 seemed to express constitutively. This suggests a complex regulation of expression of the members of the OsA family in roots and leaves under Pi starvation conditions. It has been reported that two Pht1 genes, OsPT2 and OsPT6, were highly expressed in P-starved roots of the rice cultivar Nipponbare.[10][11] In this study, the expression of these two genes is compared in wild-type and mutant plants derived from the rice cultivar Hitomebore. The expression of OsPT2 is detected in roots and leaves of the mutant and the wild type. P-starvation did not induce the expression of OsPT6 in roots of the mutant as compared with that of the wild type. In addition, knockout of OsA8did not noticeably affect the expression of other members of the Pht1 family. [1]

Expression of OsA genes in leaves and roots of the wild type and the Osa8 mutant in response to phosphorus supply. (from reference [1]).
Expression of 13 phosphate transporter genes in the Pht1 family in response to phosphorus supply in the wild type and the Osa8 mutant. (from reference [1]).

Labs working on this gene

State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China College of Agronomy, Hainan University, Danzhou, Hainan, 571737, China


  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Chang C, Hu Y, Sun S, Zhu Y, Ma G, Xu G. 2009. Proton pump OsA8 is linked to phosphorus uptake and translocation in rice. Journal of Experimental Botany 60, 557-565.
  2. 2.0 2.1 2.2 Arango M, Ge´ vaudant F, Oufattole M, Boutry M. 2003. The plasma membrane proton pump ATPase: the significance of gene subfamilies. Planta 216, 355-365.
  3. Ueno K, Kinoshita T, Inoue S, Emi T, Shimazaki K. 2005. Biochemical characterization of plasma membrane H+-ATPase activation in guard cell protoplasts of Arabidopsis thaliana in response to blue light. Plant and Cell Physiology 46, 955-963.
  4. 4.0 4.1 Palmgren MG. 2001. Plant plasma membrane H+-ATPases: power- houses for nutrient uptake. Annual Review of Plant Physiology and Plant Molecular Biology 52, 817-845.
  5. Requena N, Breuninger M, Franken P, Oco´ n A. 2003. Symbiotic status, phosphate, and sucrose regulate the expression of two plasma membrane H+-ATPase genes from the mycorrhizal fungus Glomus mosseae. Plant Physiology 132, 1540-1549.
  6. Hirano M, Hirano T. 2004. Positive and negative regulation of SMC- DNA interactions by ATP and accessory proteins. EMBO Journal 23, 2664-2673.
  7. Sondergaard TE, Schulz A, Palmgren MG. 2004. Energization of transport processes in plants. roles of the plasma membrane H+-ATPase. Plant Physiology 136, 2475-2482.
  8. Axelsen KB, Palmgren MG. 1998. Evolution of substrate specificities in the P-type ATPase superfamily. Journal of Molecular Evolution 46, 84-101.
  9. Baxter I, Tchieu J, Sussman MR, Boutry M, Palmgren MG, Gribskov M, Harper JF, Axelsen KB. 2003. Genomic comparison of P-type ATPase ion pumps in Arabidopsis and rice. Plant Physiology 132, 618-628.
  10. Paszkowski U, Kroken S, Roux C, Briggs SP. 2002. Rice phosphate transporters include an evolutionarily divergent gene specifically activated in arbuscular mycorrhizal symbiosis. Proceedings of the National Academy of Sciences, USA 99, 13324-13329.
  11. Ai P, Sun S, Zhao J, et al. 2008. Two rice phosphate transporters, OsPht1;2 and OsPht1;6, have different functions and kinetic properties in uptake and translocation. The Plant Journal doi:10.1111/j. 1365- 313x.2008.03726.x.

Structured Information