title: Phosphatidylinositol phosphate 5-kinase genes respond to phosphate deficiency for root hair elongation in Arabidopsis thaliana.
abstract: Plants drastically alter their root system architecture to adapt to different underground growth conditions. During phosphate (Pi) deficiency, most plants including Arabidopsis thaliana enhance the development of lateral roots and root hairs, resulting in bushy and hairy roots. To elucidate the signal pathway specific for the root hair elongation response to Pi deficiency, we investigated the expression of type-B phosphatidylinositol phosphate 5-kinase (PIP5K) genes, as a quantitative factor for root hair elongation in Arabidopsis. At young seedling stages, the PIP5K3 and PIP5K4 genes responded to Pi deficiency in steady-state transcript levels via PHR1-binding sequences (P1BSs) in their upstream regions. Both pip5k3 and pip5k4 single mutants, which exhibit short-root-hair phenotypes, remained responsive to Pi deficiency for root hair elongation; however the pip5k3pip5k4 double mutant exhibited shorter root hairs than the single mutants, and lost responsiveness to Pi deficiency at young seedling stages. In the tactical complementation line in which modified PIP5K3 and PIP5K4 genes with base substitutions in their P1BSs were co-introduced into the double mutant, root hairs of young seedlings had normal lengths under Pi-sufficient conditions, but were not responsive to Pi deficiency. From these results, we conclude that a Pi-deficiency signal is transferred to the pathway for root hair elongation via the PIP5K genes.
authors.affiliation: Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan.
authors.forename: Yukika
authors.initials: Y
authors.lastname: Wada
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kusano
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Tsuge
authors.forename: Takashi
authors.initials: T
authors.lastname: Aoyama
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D010641:Phenotype; D010710:Phosphates / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; C514695:PHR1 protein, Arabidopsis; D010710:Phosphates; D018129:Phosphatidylinositol Phosphates; D014157:Transcription Factors; C113567:phosphatidylinositol 5-phosphate; D017853:Phosphotransferases (Alcohol Group Acceptor); C526696:PIP5K4 protein, Arabidopsis
keywords: cis-element; phosphate deficiency; phosphatidylinositol phosphate 5-kinase; root hair elongation; transcriptional regulation