title: TRANSPARENT TESTA GLABRA2, a trichome and seed coat development gene of Arabidopsis, encodes a WRKY transcription factor.
abstract: Mutants of a new gene, TRANSPARENT TESTA GLABRA2 (TTG2), show disruptions to trichome development and to tannin and mucilage production in the seed coat. The gene was tagged by the endogenous transposon Tag1 and shown to encode a WRKY transcription factor. It is the first member of this large, plant-specific family known to control morphogenesis. The functions of all other WRKY genes revealed to date involve responses to pathogen attack, mechanical stress, and senescence. TTG2 is strongly expressed in trichomes throughout their development, in the endothelium of developing seeds (in which tannin is later generated) and subsequently in other layers of the seed coat, and in the atrichoblasts of developing roots. TTG2 acts downstream of the trichome initiation genes TTG1 and GLABROUS1, although trichome expression of TTG2 continues to occur if they are inactivated. Later, TTG2 shares functions with GLABRA2 in controlling trichome outgrowth. In the seed coat, TTG2 expression requires TTG1 function in the production of tannin. Finally, TTG2 also may be involved in specifying atrichoblasts in roots redundantly with other gene(s) but independently of TTG1 and GLABRA2.
authors.affiliation: School of Biological Sciences, P.O. Box 18, Clayton Campus, Monash University, Victoria 3800, Australia.
authors.forename: Cameron S
authors.initials: CS
authors.lastname: Johnson
authors.forename: Ben
authors.initials: B
authors.lastname: Kolevski
authors.forename: David R
authors.initials: DR
authors.lastname: Smyth
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D029681:Arabidopsis Proteins; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005966:Glucuronidase / Q000235:genetics; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D009024:Morphogenesis; D016254:Mutagenesis, Insertional; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified; D014176:Protein Biosynthesis; D012639:Seeds / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D010940:Plant Proteins; C121067:TTG1 protein, Arabidopsis; D014157:Transcription Factors; C499621:ZAP1 protein, Arabidopsis; D005966:Glucuronidase