title: Transcriptional profiling of mature Arabidopsis trichomes reveals that NOECK encodes the MIXTA-like transcriptional regulator MYB106.
abstract: Leaf hairs (trichomes) of Arabidopsis (Arabidopsis thaliana) have been extensively used as a model to address general questions in cell and developmental biology. Here, we lay the foundation for a systems-level understanding of the biology of this model cell type by performing genome-wide gene expression analyses. We have identified 3,231 genes that are up-regulated in mature trichomes relative to leaves without trichomes, and we compared wild-type trichomes with two mutants, glabra3 and triptychon, that affect trichome morphology and physiology in contrasting ways. We found that cell wall-related transcripts were particularly overrepresented in trichomes, consistent with their highly elaborated structure. In addition, trichome expression maps revealed high activities of anthocyanin, flavonoid, and glucosinolate pathways, indicative of the roles of trichomes in the biosynthesis of secondary compounds and defense. Interspecies comparisons revealed that Arabidopsis trichomes share many expressed genes with cotton (Gossypium hirsutum) fibers, making them an attractive model to study industrially important fibers. In addition to identifying physiological processes involved in the development of a specific cell type, we also demonstrated the utility of transcript profiling for identifying and analyzing regulatory gene function. One of the genes that are differentially expressed in fibers is the MYB transcription factor GhMYB25. A combination of transcript profiling and map-based cloning revealed that the NOECK gene of Arabidopsis encodes AtMYB106, a MIXTA-like transcription factor and homolog of cotton GhMYB25. However, in contrast to Antirrhinum, in which MIXTA promotes epidermal cell outgrowth, AtMYB106 appears to function as a repressor of cell outgrowth in Arabidopsis.
authors.affiliation: University of Cologne, Department of Botany III, University Group at the Max Planck Institute for Plant Breeding Research, Max-Delbrück-Laboratorium, 50829 Cologne, Germany.
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Jakoby
authors.forename: Doris
authors.initials: D
authors.lastname: Falkenhan
authors.forename: Michael T
authors.initials: MT
authors.lastname: Mader
authors.forename: Ginger
authors.initials: G
authors.lastname: Brininstool
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Wischnitzki
authors.forename: Nicole
authors.initials: N
authors.lastname: Platz
authors.forename: Andrew
authors.initials: A
authors.lastname: Hudson
authors.forename: Martin
authors.initials: M
authors.lastname: Hülskamp
authors.forename: John
authors.initials: J
authors.lastname: Larkin
authors.forename: Arp
authors.initials: A
authors.lastname: Schnittger
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D020869:Gene Expression Profiling; D012333:RNA, Messenger / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D015854:Up-Regulation
chemical_list: D029681:Arabidopsis Proteins; D012333:RNA, Messenger; D014157:Transcription Factors