BioProject

Antirrhinum R2R3 MYB transcription factor MIXTA is known to regulate epidermal cell outgrowth in petal. More...

Antirrhinum R2R3 MYB transcription factor MIXTA is known to regulate epidermal cell outgrowth in petal. Arabidopsis has three MIXTA-like proteins NOECK(NOK)/MYB106, MYB16 and MYB17 and nok mutant exhibits over-branched trichomes in rosette leaves. On the other hand, Arabidopsis AP2/ERF transcription factor WAX INDUCER1/SHINE1 is well known to induce cuticle development. Here, we report the transcriptional cascade of MYBs-WIN/SHNs coordinately regulates the epidermal cuticle development. The constitutive expression of MYB106 chimeric repressor, in which strong repression domain was fused with MYB106 (35S:MYB106SRDX), induced cuticle deficiency characterized by organ adhesion, reduction of epicuticular wax crystals and staining by toluidine blue in broad region of aerial parts in addition to the over-branched trichomes. Most these phenotypes were partially reproduced in T-DNA knockout plants and also similarly induced by the chimeric repressors of WIN1/SHINE1(SHN1), SHN2 and SHN3, which are AP2/ERF transcription factors previously shown as positive regulators of cutin. Microarray experiments revealed that MYB106SRDX and WIN1SRDX plants have similar transcriptomes, in which the expression of wax and cutin biosynthetic genes was suppressed. Conversely, VP16-fused MYB106 which has high activation ability induced ectopic production of cutin nanoridges in the transgenic plants and enhanced the reporter driven by promoters of WIN1 and wax-related genes in transient expression assay. These results suggest that MIXTA-like proteins regulate cutin biosynthesis partially via WIN1 and directly regulate wax accumulation as well as their known roles in epidermal cell differentiation. Overall design: Transcriptomes of 35S:WIN1and vector-control Arabidopsis seedling were compared. Less...