title: CYP709B3, a cytochrome P450 monooxygenase gene involved in salt tolerance in Arabidopsis thaliana.
abstract: BACKGROUND
  Within the Arabidopsis genome, there are 272 cytochrome P450 monooxygenase (P450) genes. However, the biological functions of the majority of these P450s remain unknown. The CYP709B family of P450s includes three gene members, CYP709B1, CYP709B2 and CYP709B3, which have high amino acid sequence similarity and lack reports elucidating biological functions.
  
  
  RESULTS
  We identified T-DNA insertion-based null mutants of the CYP709B subfamily of genes. No obvious morphological phenotypes were exhibited under normal growth conditions. When the responses to ABA and salt stress were studied in these mutants, only the cyp709b3 mutant showed sensitivity to ABA and salt during germination. Under moderate salt treatment (150 mM NaCl), cyp709b3 showed a higher percentage of damaged seedlings, indicating a lower tolerance to salt stress. CYP709B3 was highly expressed in all analyzed tissues and especially high in seedlings and leaves. In contrast, CYP709B1 and CYP709B2 were highly expressed in siliques, but were at very low levels in other tissues. Under salt stress condition, CYP709B3 gene expression was induced after 24 hr and remained at high expression level. Expression of the wild type CYP709B3 gene in the cyp709b3 mutant fully complemented the salt intolerant phenotype. Furthermore, metabolite profiling analysis revealed some differences between wild type and cyp709b3 mutant plants, supporting the salt intolerance phenotype of the cyp709b3 mutant.
  
  
  CONCLUSIONS
  These results suggest that CYP709B3 plays a role in ABA and salt stress response and provides evidence to support the functions of cytochrome P450 enzymes in plant stress response.
authors.forename: Guohong
authors.initials: G
authors.lastname: Mao
authors.forename: Timothy
authors.initials: T
authors.lastname: Seebeck
authors.forename: Denyse
authors.initials: D
authors.lastname: Schrenker
authors.affiliation: Donald Danforth Plant Science Center, 975 North Warson Road, St, Louis, MO 63132, USA. oliver.yu@conagen-inc.com.
authors.forename: Oliver
authors.initials: O
authors.lastname: Yu
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics*; D018525:Germination / Q000187:drug effects / Q000235:genetics; D055432:Metabolomics; D005810:Multigene Family; D016254:Mutagenesis, Insertional / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D010641:Phenotype; D055049:Salt Tolerance / Q000187:drug effects / Q000235:genetics*; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; C036483:T-DNA; D012965:Sodium Chloride; D000040:Abscisic Acid; D003577:Cytochrome P-450 Enzyme System; C000590558:cytochrome P-450 709B3, Arabidopsis