The Myb-domain protein ULTRAPETALA1 INTERACTING FACTOR 1 controls floral meristem activities in Arabidopsis

Abstract

Higher plants continuously and iteratively produce new above-ground organs in the form of leaves, stems and flowers. These organs arise from shoot apical meristems whose homeostasis depends on coordination between self-renewal of stem cells and their differentiation into organ founder cells. This coordination is stringently controlled by the central transcription factor WUSCHEL (WUS), which is both necessary and sufficient for stem cell specification in Arabidopsis thaliana. ULTRAPETALA1 (ULT1) was previously identified as a plant-specific, negative regulator of WUS expression. However, molecular mechanisms underlying this regulation remain unknown. ULT1 protein contains a SAND putative DNA-binding domain and a B-box, previously proposed as a protein interaction domain in eukaryotes. Here, we characterise a novel partner of ULT1, named ULT1 INTERACTING FACTOR 1 (UIF1), which contains a Myb domain and an EAR motif. UIF1 and ULT1 function in the same pathway for regulation of organ number in the flower. Moreover, UIF1 displays DNA-binding activity and specifically binds to WUS regulatory elements. We thus provide genetic and molecular evidence that UIF1 and ULT1 work together in floral meristem homeostasis, probably by direct repression of WUS expression.

The OsMYB30 Transcription Factor Suppresses Cold Tolerance by Interacting with a JAZ Protein and Suppressing β-Amylase Expression

“…For example, a known conserved ERF motif was identified in ERF transcriptional repressors, and the MYB repressor UIF1 was found to contain this motif (Ohta et al, 2001;Moreau et al, 2016). In addition, a novel repression motif different from the ERF motif was identified in AtMYBL2, which acted as a negative regulator of anthocyanin biosynthesis in Arabidopsis (Matsui et al, 2008).…”

QTL mapping and loci dissection for leaf epicuticular wax load and canopy temperature depression and their association with QTL for staygreen in Sorghum bicolor under stress

“…In the locus WLcs-1-32 resides an orthologue of a plantspecific Myb domain (InterPro ID: IPR006447) which is associated with transcription regulation of stress responsive genes (Rose et al 1999;Baranowskij et al 1994), leaf coloration (Gao et al 2013), floral meristem differentiation (Moreau et al 2016) and transcriptional activation (Baranowskij et al 1994). Other studies have shown that a Myb family member, MYB94 for instance, is a transcription factor that induces both stomatal closure and cuticular wax biosynthesis by upregulating directly cuticular wax biosynthetic enzyme genes such as ketoacyl synthases (KAS), the bifunctional wax ester synthase/diacylglyceral acyltransferase (WSD1), alcohol forming fatty acyl-CoA reductase (FAR) and ECERIFERUM (CER1 and CER3) (Wang et al 2014;Lee and Suh 2015).…”

Developmental transitions: integrating environmental cues with hormonal signaling in the chromatin landscape in plants

“…ARF3 binds to the chromatin of WUS in an AG-dependent manner and directly represses WUS expression to promote FM determinacy [143]. In addition, the SAND domain protein ULT1 represses WUS expression, working together with its partner ULT1 INTERACTING FACTOR 1 (UIF1), a MYB and EAR domain-containing TF that can bind to WUS regulatory regions [144]. In parallel, AtRING1a and AtRING1b (core components of the PRC1 complex) contribute to the termination of floral stem cell fate through repression of KNOX genes [145].…”