A constitutive expressed phosphate transporter, OsPht1;1, modulates phosphate uptake and translocation in phosphate-replete rice.
A number of phosphate (Pi) starvation- or mycorrhiza-regulated Pi transporters belonging to the Pht1 family have been functionally characterized in several plant species, whereas functions of the Pi transporters that are not regulated by changes in Pi supply are lacking. In this study, we show that rice (Oryza sativa) Pht1;1 (OsPT1), one of the 13 Pht1 Pi transporters in rice, was expressed abundantly and constitutively in various cell types of both roots and shoots. OsPT1 was able to complement the proton-coupled Pi transporter activities in a yeast mutant defective in Pi uptake. Transgenic plants of OsPT1 overexpression lines and RNA interference knockdown lines contained significantly higher and lower phosphorus concentrations, respectively, compared with the wild-type control in Pi-sufficient shoots. These responses of the transgenic plants to Pi supply were further confirmed by the changes in depolarization of root cell membrane potential, root hair occurrence, (33)P uptake rate and transportation, as well as phosphorus accumulation in young leaves at Pi-sufficient levels. Furthermore, OsPT1 expression was strongly enhanced by the mutation of Phosphate Overaccumulator2 (OsPHO2) but not by Phosphate Starvation Response2, indicating that OsPT1 is involved in the OsPHO2-regulated Pi pathway. These results indicate that OsPT1 is a key member of the Pht1 family involved in Pi uptake and translocation in rice under Pi-replete conditions.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China.
Shubin
S
Sun
Mian
M
Gu
Yue
Y
Cao
Xinpeng
X
Huang
Xiao
X
Zhang
Penghui
P
Ai
Jianning
J
Zhao
Xiaorong
X
Fan
Guohua
G
Xu
D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D055785:Gene Knockdown Techniques; D005816:Genetic Complementation Test; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010641:Phenotype; D028061:Phosphate Transport Proteins / Q000235:genetics / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism* / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D030821:Plants, Genetically Modified; D011522:Protons; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects
D028061:Phosphate Transport Proteins; D010710:Phosphates; D010940:Plant Proteins; D011522:Protons