Inositol Pyrophosphate lnsP8 Acts as an Intracellular Phosphate Signal in Arabidopsis  

作　　者：Jinsong Dong Guojie Ma Liqian Sui Mengwei Wei Viswanathan Satheesh Ruyue Zhang Shenghong Ge Jinkai Li Tong-En Zhang Christopher Wittwer Henning JJessen Huiming Zhang Guo-Yong An Dai-Yin Chao Dong Liu Mingguang Lei 

机构地区：[1]Shanghai Center for Plant Stress Biology,CAS Center for Excellence in Molecular Plant Sciences,Chinese Academy of Sciences,Shanghai 200032,China [2]National Key Laboratory of Plant Molecular Genetics,CAS Centre for Excellence in Molecular Plant Sciences,Shanghai Institute of Plant Physiology&Ecology,Chinese Academic of Sciences,Shanghai 200032,China [3]University of Chinese Academy of Sciences,Beijing 100049,China [4]lnstitute of Organic Chemistry,Albert-Ludwigs University,Freiburg,Albertstrasse 21,79104 Freiburg,Germany [5]C旧SS-Centre for Integrative Biological Signalling Studies,Albert-Ludwigs University,Freiburg,Albertstrasse 21,79104 Freiburg,Germany [6]Key Laboratory of Plant Stress Biology,School of Life Sciences,Henan University.Kaifeng 475004,China [7]Center for Plant Biology,School of Life Sciences,Tsinghua University,Beijing 100084,China

出　　处：《Molecular Plant》2019年第11期1463-1473,共11页分子植物（英文版）

摘　　要：The maintenance of cellular phosphate(Pi)homeostasis is of great importance in living organisms.The SPX domain-containing protein 1(SPX1)proteins from both Arabidopsis and rice have been proposed to act as sensors of Pi status.The molecular signal indicating the cellular Pi status and regulating Pi homeostasis in plants,however,remains to be identified,as Pi itself does not bind to the SPX domain.Here,we report the identification of the inositol pyrophosphate lnsP8 as a signaling molecule that regulates Pi homeostasis in Arabidopsis.Polyacrylamide gel electrophoresis profiling of InsPs revealed that lnsP8 level positively correlates with cellular Pi concentration.We demonstrated that the homologs of diphosphoinositol pentaki-sphosphate kinase(PPIP5K),VIH1 and VIH2,function redundantly to synthesize lnsP8,and that the vih1 vih2 double mutant overaccumulates Pi.SPX1 directly interacts with PHR1,the central regulator of Pi starvation responses,to inhibit its function under Pi-replete conditions.However,this interaction is compromised in the vih1 vih2 double mutant,resulting in the constitutive induction of Pi starvation-induced genes,indicating that plant cells cannot sense cellular Pi status without lnsP8.Furthermore,we showed that lnsP8 could directly bind to the SPX domain of SPX1 and is essential for the interaction between SPX1 and PHR1.Collectively,our study suggests that lnsP8 is the intracellular Pi signaling molecule serving as the ligand of SPX1 for controlling Pi homeostasis in plants.

关 键 词：nositol pyrophosphates lnsP8 phosphate signal SPX domain Pi homeostasis 

分 类 号：Q94[生物学—植物学]