title: Pyrophosphate: fructose-6-phosphate 1-phosphotransferase (PFP) regulates carbon metabolism during grain filling in rice.
abstract: Decreased PFPase activity in rice perturbs the equilibration of carbon metabolism during grain filling but has no visible phenotypic effects during the vegetative and reproductive growth stages. Starch is a primary energy reserve for various metabolic processes in plant. Despite much advance has been achieved in pathways involved in starch biosynthesis, information was still lacked for precise regulation related to carbon metabolism during seed filling in rice (Oryza sativa). The objective of this study was to identify and characterize new gene associated with carbon metabolism during grain filling. By screening our chemical mutant pool, two allelic mutants exhibiting floury endosperm were isolated. No visible phenotypic defects were observed during both the vegetative and reproductive growth stages, except for the floury-like endosperm of grains with significantly reduced kernel thickness, 1000-grain weight and total starch content. Map-based cloning revealed that the mutant phenotypes were controlled by a gene encoding pyrophosphate: fructose-6-phosphate 1-phosphotransferase (PFP, EC 2.7.1.90) β subunit (PFPβ), which catalyzes reversible interconversion between fructose-6-phosphate and fructose-1, 6-bisphosphate. The identity of PFP β was further confirmed by a genetic complementation test. Subcellular analysis demonstrated that PFPβ was localized in cytoplasm. Quantitative PCR and histochemical staining indicated PFP β was ubiquitously expressed in various tissues. Furthermore, we found PFP β could express in both the early and late phases of starch accumulation during grain filling and decreased activity of PFP β in pfp mutants resulted in compromised carbon metabolism with increased soluble sugar contents and unfavorable starch biosynthesis. Our results highlight PFPβ functions in modulating carbon metabolism during grain filling stage.
authors.affiliation: National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Erchao
authors.initials: E
authors.lastname: Duan
authors.affiliation: National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Yihua
authors.initials: Y
authors.lastname: Wang
authors.affiliation: National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Linglong
authors.initials: L
authors.lastname: Liu
authors.affiliation: National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Zhu
authors.affiliation: National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Zhong
authors.affiliation: National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310006, China.
authors.forename: Sanfeng
authors.initials: S
authors.lastname: Li
authors.affiliation: National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Baoxu
authors.initials: B
authors.lastname: Ding
authors.affiliation: National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Xiuping
authors.initials: X
authors.lastname: Guo
authors.affiliation: National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Jiang
authors.affiliation: National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China. wanjianmin@caas.cn.|National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China. wanjianmin@caas.cn.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Wan
mesh_terms: D002244:Carbon / Q000378:metabolism*; D003001:Cloning, Molecular; D002523:Edible Grain / Q000378:metabolism*; D056625:Endosperm / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D012275:Oryza / Q000201:enzymology* / Q000378:metabolism; D010770:Phosphotransferases / Q000378:metabolism / Q000502:physiology*; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D002244:Carbon; D010770:Phosphotransferases; C022502:pyrophosphate-fructose 6-phosphate 1-phosphotransferase
keywords: Carbon metabolism; Floury endosperm; Oryza sativa; Pyrophosphate: fructose-6-phosphate 1 phosphotransferase (PFP)