Overexpression of Rice Phosphate Transporter Gene OsPT2 Enhances Tolerance to Low Phosphorus Stress in Soyb ean

Abstract

Low phosphorous (P) availability in soils limits pr oduction of soybean [ Glycine max (L.) Merr.] around the world. This study was conducted t o determine whether exogenous expression of the rice ( Oryza sativa L.) phosphates transporter gene OsPT2 would increase inorganic phosphates (Pi) acquisition and improve y ield in transgenic soybean. Cotyledonary-node explants of the soybean were inoc ulated with the Agrobacterium tumefaciens strain EHA105 harboring the vector pCAMBIA3301- OsPT2 , which contained OsPT2 , gus and bar genes. Ten fertile T 0 transgenic plants were obtained and semi- quantitative RT-PCR of progenies demonstrated that OsPT2 gene was overexpressing in the T 2 generation. Three T 2 transgenic lines overexpressing OsPT2 were selected and subjected to testing for tolerance to low concentra tions of Pi (low-Pi; 20 μ M Pi) by hydroponic culture using modified Hoagland’s nutrie nt solution. The total P contents in the leaves, stems, roots, and seeds of the transgen ic plants significantly increased under the concentrations of low-Pi and 1,000 μ M Pi of standard Hoagland’s nutrient solution. Under low-Pi stress, the yields of the transgenic l ines were significantly higher than those of the wild type. Taken together, our data suggest that the overexpression of OsPT2 in transgenic soybean lines improves Pi acquisition an d seed yield, and OsPT2 may serve as one of the promising target genes that can be manip ulated in crop improvement for minor use of Pi fertilizers. Keywords: Glycine max , Transgenic plants.