The Plant Journal：水稻磷酸盐转运蛋白基因研究

南京农业大学的研究人员通过转基因手段和生物化学及生物物理方法，研究揭示了水稻中两个重要的磷酸盐转运蛋白基因的作用及其动力学特征。相关成果近日在国际植物学著名学术期刊《植物学杂志》（The Plant Journal）在线发表。
领导这一研究的是南京农业大学的徐国华教授，其于2000年在以色列耶路撒冷希伯来大学（The Hebrew University of Jerusalem）获得博士学位，曾在以色列国家科学院（WEIZMANN）进行博士后研究。徐国华主持的作物养分资源高效利用的生物学途径课题得到了 “973”项目资助。
磷是植物生长发育所必需的三大营养元素之一。磷素被植物吸收和“运输”依赖于植物体内各种各样的磷素的“挑夫”———磷酸盐转运蛋白。但不同的“挑夫”是怎样工作的，目前植物营养学界一直在探索。研究人员通过转基因手段和生物化学及生物物理方法，研究揭示了水稻中两个重要的磷酸盐转运蛋白基因的作用及其动力学特征。
据论文第一作者、南京农大在校博士生艾鹏慧介绍，由于土壤中的有效磷含量很低，植物自身就会通过改变根的形态和结构来产生大量根毛、侧根、排根以及分泌有机酸、磷酸酶等方式来尽可能地提高土壤中磷的有效性。这些磷素的吸收和利用都要借助于植物体内的“磷酸盐转运蛋白”来完成。根据对磷的吸收能力，学界把磷酸盐转运蛋白分为高亲和力转运蛋白与低亲和力转运蛋白。（生物谷Bioon.com）
生物谷推荐原始出处：
The Plant Journal，doi: 10.1111/j.1365-313X.2008.03726.x，Penghui Ai，Guohua Xu
Two rice phosphate transporters, OsPht1;2 and OsPht1;6, have different functions and kinetic properties in uptake and translocation
Penghui Ai 1, , Shubin Sun 1, , Jianning Zhao 1, , Xiaorong Fan 1 , Weijie Xin 1 , Qiang Guo 1 , Ling Yu 2 , Qirong Shen 1 , Ping Wu 3 , Anthony J. Miller 4 and Guohua Xu 1,*
1 State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China , 2 The Center for Cell and Molecular Signaling, School of Medicine, Emory University, 30322 USA , 3 State Key Laboratory of Plant Physiology and Biochemistry, College of Life Science, Zhejiang University, Hangzhou 310029, China , and 4 Centre for Soils and Ecosystem Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
Plant phosphate (Pi) transporters mediate the uptake and translocation of this nutrient within plants. A total of 13 sequences in the rice (Oryza sativa) genome can be identified as belonging to the Pi transporter (Pht1) family. Here, we report on the expression patterns, biological properties and the physiological roles of two members of the family: OsPht1;2 (OsPT2) and OsPht1;6 (OsPT6). Expression of both genes increased significantly under Pi deprivation in roots and shoots. By using transgenic rice plants expressing the GUS reporter gene, driven by their promoters, we detected that OsPT2 was localized exclusively in the stele of primary and lateral roots, whereas OsPT6 was expressed in both epidermal and cortical cells of the younger primary and lateral roots. OsPT6, but not OsPT2, was able to complement a yeast Pi uptake mutant in the high-affinity concentration range. Xenopus oocytes injected with OsPT2 mRNA showed increased Pi accumulation and a Pi-elicited depolarization of the cell membrane electrical potential, when supplied with mM external concentrations. Both results show that OsPT2 mediated the uptake of Pi in oocytes. In transgenic rice, the knock-down of either OsPT2 or OsPT6 expression by RNA interference significantly decreased both the uptake and the long-distance transport of Pi from roots to shoots. Taken together, these data suggest OsPT6 plays a broad role in Pi uptake and translocation throughout the plant, whereas OsPT2 is a low-affinity Pi transporter, and functions in translocation of the stored Pi in the plant.