title: A conifer ABI3-interacting protein plays important roles during key transitions of the plant life cycle.
abstract: ABI3 (for ABSCISIC ACID INSENSITIVE3), a transcription factor of the abscisic acid signal transduction pathway, plays a major role during seed development, dormancy inception, and dormancy maintenance. This protein appears to also function in meristematic and vegetative plant tissues and under certain stress conditions. We have isolated the ABI3 gene ortholog (CnABI3) from yellow cedar (Callitropsis nootkatensis) and found that it was functionally similar to other ABI3 genes of angiosperms. Here, we report that using a yeast (Saccharomyces cerevisiae) two-hybrid approach, we have identified another protein of yellow cedar (CnAIP2; for CnABI3 INTERACTING PROTEIN2) that physically interacts with CnABI3. Functional analyses revealed that CnAIP2 plays important roles during key transitions in the plant life cycle: (1) CnAIP2 impaired seed development and reduced seed dormancy; (2) CnAIP2 promoted root development, particularly the initiation of lateral roots, and the CnAIP2 gene promoter was exquisitely auxin sensitive; and (3) CnAIP2 promoted the transition from vegetative growth to reproductive initiation (i.e. flowering). The nature of the effects of CnAIP2 on these processes and other evidence place CnAIP2 in the category of a "global" regulator, whose actions are antagonistic to those of ABI3.
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A1S6, Canada.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zeng
authors.forename: Tiehan
authors.initials: T
authors.lastname: Zhao
authors.forename: Allison R
authors.initials: AR
authors.lastname: Kermode
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D029780:Chamaecyparis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant; D018525:Germination / Q000187:drug effects; D007150:Immunohistochemistry; D007210:Indoleacetic Acids / Q000378:metabolism; D057445:Plant Dormancy; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D011401:Promoter Regions, Genetic; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D012098:Reproduction; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins; D014157:Transcription Factors; D000040:Abscisic Acid