title: A bHLH transcription factor regulates iron intake under Fe deficiency in chrysanthemum.
abstract: Iron (Fe) deficiency can represent a serious constraint on crop growth and productivity. A number of members of the bHLH transcription factor family are known to be involved in the plant Fe deficiency response. Plants have evolved two distinct uptake strategies when challenged by Fe deficiency: dicotyledonous and non-graminaceous species rely mostly on a reduction strategy regulated by bHLH transcription factors, whereas rice relies on a chelation strategy, also regulated by bHLH transcription factors. CmbHLH1, a bHLH transcription factor which is localized within the nucleus, was isolated from chrysanthemum. Its transcription was up-regulated both by Fe deficiency and by the exogenous application of abscisic acid. The roots of transgenic chrysanthemum plants in which CmbHLH1 was up-regulated were better able than those of the wild type chrysanthemum cultivar to acidify their immediate external environment by enhancing the transcription of the H(+)-ATPase encoding gene CmHA. However, there was no effect of the transgene on the efficiency of uptake of either manganese or zinc. Here, Chrysanthemum CmbHLH1 contributed to Fe uptake via H(+)-ATPase mediated acidification of the rhizosphere. ABA may be positively involved in the process.
authors.affiliation: College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhao
authors.affiliation: College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Aiping
authors.initials: A
authors.lastname: Song
authors.affiliation: College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Peiling
authors.initials: P
authors.lastname: Li
authors.affiliation: College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Sumei
authors.initials: S
authors.lastname: Chen
authors.affiliation: College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Jiafu
authors.initials: J
authors.lastname: Jiang
authors.affiliation: College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Fadi
authors.initials: F
authors.lastname: Chen
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D031202:Chrysanthemum / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D042541:Intracellular Space / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D000090463:Iron Deficiencies; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D021381:Protein Transport; D020218:Response Elements; D058441:Rhizosphere
chemical_list: D000040:Abscisic Acid; D051792:Basic Helix-Loop-Helix Proteins; D007501:Iron