title: Auxin Response Factor2 (ARF2) and its regulated homeodomain gene HB33 mediate abscisic acid response in Arabidopsis.
abstract: The phytohormone abscisic acid (ABA) is an important regulator of plant development and response to environmental stresses. In this study, we identified two ABA overly sensitive mutant alleles in a gene encoding Auxin Response Factor2 (ARF2). The expression of ARF2 was induced by ABA treatment. The arf2 mutants showed enhanced ABA sensitivity in seed germination and primary root growth. In contrast, the primary root growth and seed germination of transgenic plants over-expressing ARF2 are less inhibited by ABA than that of the wild type. ARF2 negatively regulates the expression of a homeodomain gene HB33, the expression of which is reduced by ABA. Transgenic plants over-expressing HB33 are more sensitive, while transgenic plants reducing HB33 by RNAi are more resistant to ABA in the seed germination and primary root growth than the wild type. ABA treatment altered auxin distribution in the primary root tips and made the relative, but not absolute, auxin accumulation or auxin signal around quiescent centre cells and their surrounding columella stem cells to other cells stronger in arf2-101 than in the wild type. These results indicate that ARF2 and HB33 are novel regulators in the ABA signal pathway, which has crosstalk with auxin signal pathway in regulating plant growth.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Deping
authors.initials: D
authors.lastname: Hua
authors.forename: Junna
authors.initials: J
authors.lastname: He
authors.forename: Ying
authors.initials: Y
authors.lastname: Duan
authors.forename: Zhizhong
authors.initials: Z
authors.lastname: Chen
authors.forename: Xuhui
authors.initials: X
authors.lastname: Hong
authors.forename: Zhizhong
authors.initials: Z
authors.lastname: Gong
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D047369:Chromatin Immunoprecipitation; D019926:Cyclin B / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics*; D018525:Germination / Q000187:drug effects; D005966:Glucuronidase / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D034622:RNA Interference / Q000187:drug effects; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012639:Seeds / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D019926:Cyclin B; D005966:Glucuronidase; D018398:Homeodomain Proteins; D007210:Indoleacetic Acids; D012097:Repressor Proteins; C503421:ARF2 protein, Arabidopsis; C462528:CycB1 protein, Arabidopsis; C570097:At1g75240 protein, Arabidopsis