Abstract
Background and aims
Whereas the expression patterns and kinetic properties of the rice (Oryza sativa) phosphate transporter gene OsPht1; 6 (OsPT6) are well documented, little is known about the biological functions of this gene. The aim of this study was to investigate the roles of OsPT6 in inorganic phosphate (Pi) acquisition and mobilization, and examine its potential to enhance agricultural production.
Methods
Here, we generated OsPT6 overexpression transgenic plants using Wuyujing 7, a widely cultivated variety of japonica rice, and then treated transgenic lines and wild type with different Pi supply in hydroponic and soil experiments to explore the functions of OsPT6 in rice.
Results
The OsPT6-overexpressing rice lines grew better and accumulated more biomass than wild-type plants, and exhibited significant increases in P accumulation in various tissues, including reproductive tissues under both hydroponic and soil culture conditions. Phosphate-uptake experiment using radiolabeled Pi (33P) showed that the rate of Pi uptake was 75 % and 73 % greater in transgenic plants grown under Pi-sufficient and -deficient conditions, respectively, than the wild-type controls, and that the shoot/root ratio of 33P was 104 % and 42 % greater, respectively. In addition, the grain yield per transgenic plant was much higher than that of the wild-type plants under field conditions.
Conclusions
Taken together, our results demonstrate that OsPT6 plays a vital role in Pi acquisition and mobilization in rice and suggest that this gene may be used for genetic engineering rice plants that require less Pi fertilizer.
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Acknowledgments
This work was supported by the China 973 Program (2011CB100300), China National Natural Science Foundation (31172014), Jiangsu Provincial Natural Science Foundation (BK20141367), the National Program on R&D of Transgenic Plants (2008ZX08001-005;2011ZX08009-003-005; 2014ZX0800931B), and the PAPD project in Jiangsu Province of China, 111 project (No. B12009).
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Supplemental Fig. S1
The ratio of total P concentrations in young leaves to old leaves of wild-type plants (Nipponbare) and OsPT6-Ox plants, at the mature stage. DW, dry weight. Error bars indicate the SE (n=5). Significant differences between the wild type (WT) and transgenic lines are indicated with different letters (P < 0.05, one-way ANOVA). (DOCX 96 kb)
Supplemental Fig. S2
The Pi-regulated transcript levels of OsPT6 in roots and shoots of rice cv. Wuyujing 7. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis of OsPT6 expression in different tissues. The number of PCR cycles was 32 for the amplification of OsPT6, and 27 for OsActin. PCR were performed using primers specific for OsPT6 (Supplemental Table). The expression of OsActin was used as an internal control.. (DOCX 75 kb)
Supplemental Fig. S3
Photo of root systems of the wild-type and OsPT6-Ox plants. 10-d-old seedlings were transferred to nutrient solution, grown under Pi-sufficient (0.3 mM Pi, +P) or Pi-deficient (0.01 mM Pi, -P) conditions for 3 weeks, and then scanned the plant roots by Mac/WinRHI-ZOTMs. (DOCX 88 kb)
Supplemental Fig. S4
The shoot biomass (A) and total P content (B) of OsPT6-Ox and wild type at harvest stage. The OsPT6-Ox in the x-axis of (A) and (B) indicated numerical value of transgenic lines (Ox1, Ox2, and Ox3) on average. All plants were grown in standard paddy fields, the planting density was 20 cm between plants in a row, and rows were 25 cm apart. The shoot included leaf blades, leaf sheathes and culms. DW, dry weight. Error bars represent ± SE (n=5). Significant differences between the wild-type (WT) and OsPT6-Ox are indicated with different letters (P < 0.05, one-way ANOVA). (DOCX 79 kb)
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Zhang, F., Wu, XN., Zhou, HM. et al. Overexpression of rice phosphate transporter gene OsPT6 enhances phosphate uptake and accumulation in transgenic rice plants. Plant Soil 384, 259–270 (2014). https://doi.org/10.1007/s11104-014-2168-8
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DOI: https://doi.org/10.1007/s11104-014-2168-8