Transcriptome Analysis of Arabidopsis Wild-Type and gl3–sst sim Trichomes Identifies Four Additional Genes Required for Trichome Development

Abstract

Transcriptome analyses have been performed on mature trichomes isolated from wild-type Arabidopsis leaves and on leaf trichomes isolated from the gl3–sst sim double mutant, which exhibit many attributes of immature trichomes. The mature trichome profile contained many highly expressed genes involved in cell wall synthesis, protein turnover, and abiotic stress response. The most highly expressed genes in the gl3–sst sim profile encoded ribosomal proteins and other proteins involved in translation. Comparative analyses showed that all but one of the genes encoding transcription factors previously found to be important for trichome formation, and many other trichome-important genes, were preferentially expressed in gl3–sst sim trichomes. The analysis of genes preferentially expressed in gl3–sst sim led to the identification of four additional genes required for normal trichome development. One of these was the HDG2 gene, which is a member of the HD–ZIP IV transcription factor gene family. Mutations in this gene did not alter trichome expansion, but did alter mature trichome cell walls. Mutations in BLT resulted in a loss of trichome branch formation. The relationship between blt and the phenotypically identical mutant, sti, was explored. Mutations in PEL3, which was previously shown to be required for development of the leaf cuticle, resulted in the occasional tangling of expanding trichomes. Mutations in another gene encoding a protein with an unknown function altered trichome branch formation.

SIAMESE Cooperates With the CDH1-like Protein CCS52A1 to Establish Endoreplication in Arabidopsis thaliana Trichomes

“…Furthermore, expression of CCS52A2 from the GL2 promoter was capable of complementing the ccs52a1 mutant phenotype ( Figure 2E). These results are consistent with microarray results indicating that CCS52A1 transcripts are detectable in trichomes in microarray experiments, while CCS52A2 transcripts are not (Marks et al 2009). …”

Arabidopsishomeodomain-leucine zipper IV proteins promote stomatal development and ectopically induce stomata beyond the epidermis

“…S7) (Hülskamp, 2004). hdg2 trichomes do not have growth/morphological phenotypes, but exhibit altered cuticle textures (Marks et al, 2009). Further studies, such as cell typespecific manipulation of HDG2 activity and identification of its targets, may provide a direct link between HDG2-mediated epidermal identity, cell proliferation and stomatal differentiation.…”

Actin-Dependent and -Independent Functions of Cortical Microtubules in the Differentiation ofArabidopsisLeaf Trichomes

“…Accordingly, the microtubule collar could function in delivering proteins to the "bulge to come." It is too early to pinpoint which proteins are involved (yellow cloud in model of Figure 8A), but proteins such as BRANCHLESS TRICHOME and STICHEL, which have been seen to accumulate at the tip of early trichome branches (Ilgenfritz et al, 2003;Marks et al, 2009), are potential candidates.…”