The START domain potentiates HD-ZIPIII transcriptional activity.

The CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIPIII) transcription factors (TFs) were repeatedly deployed over 725 million years of evolution to regulate central developmental innovations. The START domain of this pivotal class of developmental regulators was recognized over 20 years ago, but its putative ligands and functional contributions remain unknown. Here, we demonstrate that the START domain promotes HD-ZIPIII TF homodimerization and increases transcriptional potency.

Genome-wide analysis of plant miRNA action clarifies levels of regulatory dynamics across developmental contexts.

Development of complex organisms requires the delicate and dynamic spatiotemporal regulation of gene expression. Central to this are microRNAs (miRNAs). These mobile small RNAs offer specificity in conveying positional information and versatility in patterning the outcomes of gene expression.

Nonsense Mutation Inside Anthocyanidin Synthase Gene Controls Pigmentation in Yellow Raspberry ( L.).

Yellow raspberry fruits have reduced anthocyanin contents and offer unique possibility to study the genetics of pigment biosynthesis in this important soft fruit. Anthocyanidin synthase () catalyzes the conversion of leucoanthocyanidin to anthocyanidin, a key committed step in biosynthesis of anthocyanins. Molecular analysis of the gene enabled to identify an inactive allele in a yellow fruit raspberry ("Anne").

Discovery of A-type procyanidin dimers in yellow raspberries by untargeted metabolomics and correlation based data analysis.

Introduction: Raspberries are becoming increasingly popular due to their reported health beneficial properties. Despite the presence of only trace amounts of anthocyanins, yellow varieties seems to show similar or better effects in comparison to conventional raspberries.

Objectives: The aim of this work is to characterize the metabolic differences between red and yellow berries, focussing on the compounds showing a higher concentration in yellow varieties.

Formation of β-glucogallin, the precursor of ellagic acid in strawberry and raspberry.

Ellagic acid/ellagitannins are plant polyphenolic antioxidants that are synthesized from gallic acid and have been associated with a reduced risk of cancer and cardiovascular diseases. Here, we report the identification and characterization of five glycosyltransferases (GTs) from two genera of the Rosaceae family (Fragaria and Rubus; F. × ananassa FaGT2*, FaGT2, FaGT5, F.

A targeted metabolomics approach to understand differences in flavonoid biosynthesis in red and yellow raspberries.

Phenolic compounds account for the most important class of secondary metabolites in raspberries and fulfill a broad range of biological functions in plants. Due to their presence in fruits they are also considered as important bioactive compounds in human nutrition and are closely related to fruit quality. In the present study a targeted UPLC-MS/MS method was used to screen various phenolic compounds in fruits of red and yellow raspberry cultivars.

A genome-wide regulatory framework identifies maize pericarp color1 controlled genes.

Pericarp Color1 (P1) encodes an R2R3-MYB transcription factor responsible for the accumulation of insecticidal flavones in maize (Zea mays) silks and red phlobaphene pigments in pericarps and other floral tissues, which makes P1 an important visual marker. Using genome-wide expression analyses (RNA sequencing) in pericarps and silks of plants with contrasting P1 alleles combined with chromatin immunoprecipitation coupled with high-throughput sequencing, we show here that the regulatory functions of P1 are much broader than the activation of genes corresponding to enzymes in a branch of flavonoid biosynthesis. P1 modulates the expression of several thousand genes, and ∼1500 of them were identified as putative direct targets of P1.

Regulatory switch enforced by basic helix-loop-helix and ACT-domain mediated dimerizations of the maize transcription factor R.

The maize R2R3-MYB regulator C1 cooperates with the basic helix-loop-helix (bHLH) factor R to activate the expression of anthocyanin biosynthetic genes coordinately. As is the case for other bHLH factors, R harbors several protein-protein interaction domains. Here we show that not the classical but rather a briefly extended R bHLH region forms homodimers that bind canonical G-box DNA motifs.

Evolutionary and comparative analysis of MYB and bHLH plant transcription factors.

The expansion of gene families encoding regulatory proteins is typically associated with the increase in complexity characteristic of multi-cellular organisms. The MYB and basic helix-loop-helix (bHLH) families provide excellent examples of how gene duplication and divergence within particular groups of transcription factors are associated with, if not driven by, the morphological and metabolic diversity that characterize the higher plants. These gene families expanded dramatically in higher plants; for example, there are approximately 339 and 162 MYB and bHLH genes, respectively, in Arabidopsis, and approximately 230 and 111, respectively, in rice.

Cloning and characterization of a UV-B-inducible maize flavonol synthase.

Flavonols are important compounds for conditional male fertility in maize (Zea mays) and other crops, and they also contribute to protecting plants from UV-B radiation. However, little continues to be known on how maize and other grasses synthesize flavonols, and how flavonol biosynthesis is regulated. By homology with an Arabidopsis flavonol synthase (AtFLS1), we cloned a maize gene encoding a protein (ZmFLS1) capable of converting the dihydrokaempferol (DHK) and dihydroquercetin (DHQ) dihydroflavonols to the corresponding flavonols, kaempferol (K) and quercetin (Q).

The basic helix loop helix domain of maize R links transcriptional regulation and histone modifications by recruitment of an EMSY-related factor.

The control of anthocyanin accumulation in maize by the cooperation of the basic helix-loop-helix (bHLH) protein R with the MYB transcription factor C1 provides one of the best examples of plant combinatorial transcriptional control. Establishing the function of the bHLH domain of R has remained elusive, and so far no proteins that interact with this conserved domain have been identified. We show here that the bHLH domain of R is dispensable for the activation of transiently expressed genes yet is essential for the activation of the endogenous genes in their normal chromatin environment.

A trafficking pathway for anthocyanins overlaps with the endoplasmic reticulum-to-vacuole protein-sorting route in Arabidopsis and contributes to the formation of vacuolar inclusions.

Plants produce a very large number of specialized compounds that must be transported from their site of synthesis to the sites of storage or disposal. Anthocyanin accumulation has provided a powerful system to elucidate the molecular and cellular mechanisms associated with the intracellular trafficking of phytochemicals. Benefiting from the unique fluorescent properties of anthocyanins, we show here that in Arabidopsis (Arabidopsis thaliana), one route for anthocyanin transport to the vacuole involves vesicle-like structures shared with components of the secretory pathway.

An ACT-like domain participates in the dimerization of several plant basic-helix-loop-helix transcription factors.

The maize basic-helix-loop-helix (bHLH) factor R belongs to a group of proteins with important functions in the regulation of metabolism and development through the cooperation with R2R3-MYB transcription factors. Here we show that in addition to the bHLH and the R2R3-MYB-interacting domains, R contains a dimerization region located C-terminal to the bHLH motif. This protein-protein interaction domain is important for the regulation of anthocyanin pigment biosynthesis by contributing to the recruitment of the C1 R2R3-MYB factor to the C1 binding sites present in the promoters of flavonoid biosynthetic genes.

Different mechanisms participate in the R-dependent activity of the R2R3 MYB transcription factor C1.

The R2R3 MYB transcription factor C1 requires the basic helix-loop-helix factor R as an essential co-activator for the transcription of maize anthocyanin genes. In contrast, the R2R3 MYB protein P1 activates a subset of the C1-regulated genes independently of R. Substitution of six amino acids in P1 with the C1 amino acids results in P1(*), whose activity on C1-regulated and P1-regulated genes is R-dependent or R-enhanced, respectively.