Simultaneous mutations in ITPK4 and MRP5 genes result in a low phytic acid level without compromising salt tolerance in Arabidopsis  

作　　者：Yuying Ren Mengdan Jiang Jian-Kang Zhu Wenkun Zhou Chunzhao Zhao 

机构地区：[1]Key Laboratory of Plant Design,National Key Laboratory of Plant Molecular Genetics,Shanghai Center for Plant Stress Biology,CAS Center for Excellence in Molecular Plant Sciences,the Chinese Academy of Sciences,Shanghai 200032,China [2]University of Chinese Academy of Sciences,Beijing 100190,China [3]State Key Laboratory of Plant Environmental Resilience,College of Biological Sciences,China Agricultural University,Beijing 100193,China [4]Institute of Advanced Biotechnology and School of Life Sciences,Southern University of Science and Technology,Shenzhen 518055,China [5]Ministry of Agriculture and Rural Affairs Key Laboratory of Gene Editing Technologies,Nanfan Research Institute,Chinese Academy of Agricultural Sciences,Sanya 572024,China

出　　处：《Journal of Integrative Plant Biology》2024年第10期2109-2125,共17页植物学报（英文版）

基　　金：supported by the Science and Technology Commission of Shanghai Municipality(Grant No.22ZR1469600);the National Natural Science Foundation of China(Grant Nos.32270283 and 32070295);the National Key Research and Development Program of China(Grant No.2023YFF1002100);the Key Laboratory of Plant Design;the National Key Laboratory of Plant Molecular Genetics。

摘　　要：Generation of crops with low phytic acid(myoinositol-1,2,3,4,5,6-hexakisphosphate(InsP6))is an important breeding direction,but such plants often display less desirable agronomic traits.In this study,through ethyl methanesulfonate-mediated mutagenesis,we found that inositol 1,3,4-trisphosphate5/6-kinase 4(ITPK4),which is essential for producing InsP6,is a critical regulator of salt tolerance in Arabidopsis.Loss of function of ITPK4 gene leads to reduced root elongation under salt stress,which is primarily because of decreased root meristem length and reduced meristematic cell number.The itpk4 mutation also results in increased root hair density and increased accumulation of reactive oxygen species during salt exposure.RNA sequencing assay reveals that several auxin-responsive genes are down-regulated in the itpk4-1 mutant compared to the wild-type.Consistently,the itpk4-1 mutant exhibits a reduced auxin level in the root tip and displays compromised gravity response,indicating that ITPK4 is involved in the regulation of the auxin signaling pathway.Through suppressor screening,it was found that mutation of Multidrug Resistance Protein 5(MRP5)5 gene,which encodes an ATP-binding cassette(ABC)transporter required for transporting InsP6from the cytoplasm into the vacuole,fully rescues the salt hypersensitivity of the itpk4-1 mutant,but in the itpk4-1 mrp5 double mutant,InsP6remains at a very low level.These results imply that InsP6homeostasis rather than its overall amount is beneficial for stress tolerance in plants.Collectively,this study uncovers a pair of gene mutations that confer low InsP6content without impacting stress tolerance,which offers a new strategy for creating“low-phytate”crops.

关 键 词：ITPK4 MRP5 phytic acid root elongation salt stress 

分 类 号：Q943.2[生物学—植物学]