title: Overexpression of FTL1/DDF1, an AP2 transcription factor, enhances tolerance to cold, drought, and heat stresses in Arabidopsis thaliana.
abstract: Freezing temperatures control where and when plants can grow, and negatively influence crop quality and productivity. To identify key regulatory genes involved in cold adaptation, we screened activation-tagged Arabidopsis lines for mutants with greater freezing tolerance. One mutant, freezing tolerant line1 (ftl1-1D), manifested enhanced tolerance along with dwarfism and delayed flowering. This was caused by activation of DWARF AND DELAYED FLOWERING 1 (DDF1), a gene previously described as a regulatory component in salinity signaling. The induced gene encoded an AP2 transcription factor of the CBF/DREB1 subfamily. In addition to conferring tolerance to low temperatures and salt stress, ftl1-1D/ddf1 improved tolerance to drought and heat. Real-time PCR indicated that FTL1/DDF1 was up-regulated by those four types of stresses in wild-type Arabidopsis. Its increased expression in the mutant induced various stress-responsive genes under normal growing conditions, resulting in improved tolerances. However, phenotypes shown in the ftl1-1D/ddf1 were restored by treatment with exogenous gibberellin (GA₃), indicating the involvement of a GA pathway in FTL1/DDF1-mediated tolerance. Therefore, we conclude that FTL1/DDF1 plays a role in regulating responses to several abiotic stresses, perhaps via cross-talk in the pathways.
authors.affiliation: Subtropical Horticulture Research Institute, Cheju National University, Jeju 690-756, Republic of Korea.
authors.forename: Hong-Gyu
authors.initials: HG
authors.lastname: Kang
authors.forename: Joonki
authors.initials: J
authors.lastname: Kim
authors.forename: Bohwa
authors.initials: B
authors.lastname: Kim
authors.forename: Hana
authors.initials: H
authors.lastname: Jeong
authors.forename: Sun Hee
authors.initials: SH
authors.lastname: Choi
authors.forename: Eun Kyoung
authors.initials: EK
authors.lastname: Kim
authors.forename: Hyo-Yeon
authors.initials: HY
authors.lastname: Lee
authors.forename: Pyung Ok
authors.initials: PO
authors.lastname: Lim
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D003080:Cold Temperature; D058639:Cold-Shock Response; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D006358:Hot Temperature; D009154:Mutation; D013312:Stress, Physiological / Q000235:genetics*; D014867:Water / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C487098:DDF1 protein, Arabidopsis; D014867:Water