title: BOTRYTIS-INDUCED KINASE1, a plasma membrane-localized receptor-like protein kinase, is a negative regulator of phosphate homeostasis in Arabidopsis thaliana.
abstract: Plants have evolved complex coordinated regulatory networks to cope with deficiency of phosphate (Pi) in their growth environment; however, the detailed molecular mechanisms that regulate Pi sensing and signaling pathways are not fully understood yet. We report here that the involvement of Arabidopsis BIK1, a plasma membrane-localized receptor-like protein kinase that plays critical role in immunity, in Pi starvation response.
  
  
  
  qRT-PCR analysis revealed that expression of BIK1 was induced by Pi starvation and GUS staining indicated that the BIK1 promoter activity was detected in root, stem and leaf tissues of plants grown in Pi starvation condition, demonstrating that BIK1 is responsive to Pi starvation stress. The bik1 plants accumulated higher Pi content in root and leaf tissues and exhibited altered root architecture such as shorter primary roots, longer and more root hairs and lateral roots, as compared with those in the wild type plants, when grown under Pi sufficient and deficient conditions. Increased anthocyanin content and acid phosphatase activity, reduced accumulation of reactive oxygen species and downregulated expression of Pi starvation-induced genes including PHR1, WRKY75, AT4, PHT1;2 and PHT1;4 were observed in bik1 plants grown under Pi deficient condition. Furthermore, the expression of PHO2 was downregulated while the expression of miRNA399a and miRNA399d, which target to PHO2, was upregulated in bik1 plants, compared to the wild type plants, when grown under Pi deficient condition.
  
  
  
  Our results demonstrate that BIK1 is a Pi starvation-responsive gene that functions as a negative regulator of Pi homeostasis in Arabidopsis.
authors.affiliation: College of Life Science, Taizhou University, Taizhou, Zhejiang, 318001, People's Republic of China.|National Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: National Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Huang
authors.affiliation: National Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China.
authors.forename: Yongbo
authors.initials: Y
authors.lastname: Hong
authors.affiliation: National Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China. fmsong@zju.edu.cn.
authors.forename: Fengming
authors.initials: F
authors.lastname: Song
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D006706:Homeostasis; D010710:Phosphates / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D029681:Arabidopsis Proteins; D010710:Phosphates; C509522:BIK1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases
keywords: BOTRYTIS-INDUCED KINASE1 (BIK1); Phosphate starvation response; Phosphate starvation stress; Root architecture