title: Pectin enhances rice (Oryza sativa) root phosphorus remobilization.
abstract: Plants growing in phosphorus (P)-deficient conditions can either increase their exploration of the environment (hence increasing P uptake) or can solubilize and reutilize P from established tissue sources. However, it is currently unclear if P stored in root cell wall can be reutilized. The present study shows that culture of the rice cultivars 'Nipponbare' (Nip) and 'Kasalath' (Kas) in P-deficient conditions results in progressive reductions in root soluble inorganic phosphate (Pi). However, Nip consistently maintains a higher level of soluble Pi and lower relative cell wall P content than does Kas, indicating that more cell wall P is released in Nip than in Kas. P-deficient Nip has a greater pectin and hemicellulose 1 (HC1) content than does P-deficient Kas, consistent with the significant positive relationship between pectin and root-soluble Pi levels amongst multiple rice cultivars. These observations suggest that increased soluble Pi might result from increased pectin content during P starvation. In vitro experiments showed that pectin releases Pi from insoluble FePO4. Furthermore, an Arabidopsis thaliana mutant with reduced pectin levels (qua1-2), has less root soluble Pi and is more sensitive to P deficiency than the wild type (WT) Col-0, whereas NaCl-treated WT plants exhibit both an increased root pectin content and an elevated soluble Pi content during P-starvation. These observations indicate that pectin can facilitate the remobilization of P deposited in the cell wall. This is a previously unknown mechanism for the reutilization of P in P-starved plants.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences; Zhejiang University, Hangzhou 310058, China.
authors.forename: Xiao Fang
authors.initials: XF
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences; Zhejiang University, Hangzhou 310058, China.
authors.forename: Zhi Wei
authors.initials: ZW
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences; Zhejiang University, Hangzhou 310058, China.
authors.forename: Jiang Xue
authors.initials: JX
authors.lastname: Wan
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences; Zhejiang University, Hangzhou 310058, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences; Zhejiang University, Hangzhou 310058, China.
authors.forename: Yun Rong
authors.initials: YR
authors.lastname: Wu
authors.affiliation: College of Agronomy and Biotechnology, Zhejiang University, Hangzhou 310058, China.
authors.forename: Gui Xin
authors.initials: GX
authors.lastname: Li
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, China Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China.
authors.forename: Ren Fang
authors.initials: RF
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences; Zhejiang University, Hangzhou 310058, China sjzheng@zju.edu.cn.
authors.forename: Shao Jian
authors.initials: SJ
authors.lastname: Zheng
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D009154:Mutation; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010368:Pectins / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism
chemical_list: D010710:Phosphates; D010940:Plant Proteins; D010758:Phosphorus; D010368:Pectins
keywords: Arabidopsis.; Phosphorus deficiency; cell wall; hemicellulose; pectin; rice