Phosphate uptake and growth characteristics of transgenic rice with phosphate transporter 1 (OsPT1) gene overexpression under high phosphate soils

Abstract

Farmers have used phosphate fertilizer to provide sufficient yields. However, overuse of phosphorus accumulate in soil and causes soil and water pollution. We evaluated the phosphate acquisition and growth characteristics of OsPT1 transgenic rice (OsPT1-OX, over-expressing the high affinity phosphate transporter 1) in high phosphate soils with different level of nitrogen fertilizer treatment to investigate its removal ability of excessive phosphate from soil. OsPT1-OX had shorter culm length but more tillers than those of wild-type plants in each soil conditions. Phosphate content per dry weight of OsPT1-OX was 1.8 times higher than that of wild-type under control fertilizer treated conditions. Although the dry weight of OsPT1-OX was not different from that of wild-type plants, whole plant phosphate content was 1.7 times higher than that of wild-type plants under control fertilizer conditions. Tiller number and phosphate content per dry weight of wild-type plants increased following high levels of phosphate application, but did not change following additional nitrogen application. Tiller number and phosphate content per dry weight of OsPT1-OX did not also change under the high phosphate condition, but increased following nitrogen application under similar conditions. Whole plant phosphate content was also highest under high nitrogen and high phosphate application conditions. These results suggest that OsPT1-OX may reduce phosphate content in soils containing excess phosphate and may be further effective under high nitrogen condition.

Key words: Phosphate content, fertilizer treatment, phosphate transporter, rice, soil.