Chloroplasts prevent precocious flowering through a GOLDEN2-LIKE-B-BOX DOMAIN PROTEIN module.

The timing of flowering is tightly controlled by signals that integrate environmental and endogenous cues. Sugars produced by carbon fixation in the chloroplast are a crucial endogenous cue for floral initiation. Chloroplasts also convey information directly to the nucleus through retrograde signaling to control plant growth and development.

Profiling Protein-DNA Interactions by Chromatin Immunoprecipitation in Arabidopsis.

In plant cells, transcription factors play an important role in the regulation of gene expression, which eventually leads to the formation of complex phenotypes. Although chromatin immunoprecipitation (ChIP) involves a lengthy process that requires up to 4 days to complete, it is a powerful technique to investigate the interactions between transcription factors and their target sequences in vivo. Here, we describe a detailed ChIP protocol, focusing on ChIP-qPCR, from material collection to data analyses.

PHOSPHORYLETHANOLAMINE CYTIDYLYLTRANSFERASE 1 modulates flowering in a florigen-independent manner by regulating .

PHOSPHORYLETHANOLAMINE CYTIDYLYLTRANSFERASE 1 (PECT1) regulates phosphatidylethanolamine biosynthesis and controls the phosphatidylethanolamine:phosphatidylcholine ratio in Previous studies have suggested that PECT1 regulates flowering time by modulating the interaction between phosphatidylcholine and FLOWERING LOCUS T (FT), a florigen, in the shoot apical meristem (SAM). Here, we show that knockdown of by artificial microRNA in the SAM () accelerated flowering under inductive and even non-inductive conditions, in which transcription is almost absent, and in double mutants under both conditions. Transcriptome analyses suggested that PECT1 affects flowering by regulating () and ().

Arabidopsis ABF3 and ABF4 Transcription Factors Act with the NF-YC Complex to Regulate SOC1 Expression and Mediate Drought-Accelerated Flowering.

The drought-escape response accelerates flowering in response to drought stress, allowing plants to adaptively shorten their life cycles. Abscisic acid (ABA) mediates plant responses to drought, but the role of ABA-responsive element (ABRE)-binding factors (ABFs) in the drought-escape response is poorly understood. Here, we show that Arabidopsis thaliana ABF3 and ABF4 regulate flowering in response to drought through transcriptional regulation of the floral integrator SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1).

CC-type glutaredoxins mediate plant response and signaling under nitrate starvation in Arabidopsis.

Background: Nitrogen is an essential nutrient in plants. Despite the importance of nitrogen for plant growth and agricultural productivity, signal transduction pathways in response to nitrate starvation have not been fully elucidated in plants.

Results: Gene expression analysis and ectopic expression were used to discover that many CC-type glutaredoxins (ROXYs) are differentially expressed in response to nitrate deprivation.

PHO1 Exports Phosphate from the Chalazal Seed Coat to the Embryo in Developing Arabidopsis Seeds.

Seed production requires the transfer of nutrients from the maternal seed coat to the filial endosperm and embryo. Because seed coat and filial tissues are symplasmically isolated, nutrients arriving in the seed coat via the phloem must be exported to the apoplast before reaching the embryo. Proteins implicated in the transfer of inorganic phosphate (Pi) from the seed coat to the embryo are unknown despite seed P content being an important agronomic trait.

Control of plant phosphate homeostasis by inositol pyrophosphates and the SPX domain.

Proteins containing a SPX domain are involved in phosphate (Pi) homeostasis, including Pi transport and adaptation to Pi deficiency. The SPX domain harbors a basic surface binding Pi at low affinity and inositol pyrophosphates (PP-InsPs) at high affinity. Genetic and biochemical studies revealed that PP-InsPs serve as ligands for the SPX domain.

SCYL2 Genes Are Involved in Clathrin-Mediated Vesicle Trafficking and Essential for Plant Growth.

Protein transport between organelles is an essential process in all eukaryotic cells and is mediated by the regulation of processes such as vesicle formation, transport, docking, and fusion. In animals, SCY1-LIKE2 (SCYL2) binds to clathrin and has been shown to play roles in trans-Golgi network-mediated clathrin-coated vesicle trafficking. Here, we demonstrate that SCYL2A and SCYL2B, which are Arabidopsis () homologs of animal SCYL2, are vital for plant cell growth and root hair development.

Control of eukaryotic phosphate homeostasis by inositol polyphosphate sensor domains.

Phosphorus is a macronutrient taken up by cells as inorganic phosphate (P(i)). How cells sense cellular P(i) levels is poorly characterized. Here, we report that SPX domains--which are found in eukaryotic phosphate transporters, signaling proteins, and inorganic polyphosphate polymerases--provide a basic binding surface for inositol polyphosphate signaling molecules (InsPs), the concentrations of which change in response to P(i) availability.

The EXS Domain of PHO1 Participates in the Response of Shoots to Phosphate Deficiency via a Root-to-Shoot Signal.

The response of shoots to phosphate (Pi) deficiency implicates long-distance communication between roots and shoots, but the participating components are poorly understood. We have studied the topology of the Arabidopsis (Arabidopsis thaliana) PHOSPHATE1 (PHO1) Pi exporter and defined the functions of its different domains in Pi homeostasis and signaling. The results indicate that the amino and carboxyl termini of PHO1 are both oriented toward the cytosol and that the protein spans the membrane twice in the EXS domain, resulting in a total of six transmembrane α-helices.

Heterologous expression of chloroplast-localized geranylgeranyl pyrophosphate synthase confers fast plant growth, early flowering and increased seed yield.

Geranylgeranyl pyrophosphate synthase (GGPS) is a key enzyme for a structurally diverse class of isoprenoid biosynthetic metabolites including gibberellins, carotenoids, chlorophylls and rubber. We expressed a chloroplast-targeted GGPS isolated from sunflower (Helianthus annuus) under control of the cauliflower mosaic virus 35S promoter in tobacco (Nicotiana tabacum). The resulting transgenic tobacco plants expressing heterologous GGPS showed remarkably enhanced growth (an increase in shoot and root biomass and height), early flowering, increased number of seed pods and greater seed yield compared with that of GUS-transgenic lines (control) or wild-type plants.

Ethylene mediates response and tolerance to potassium deprivation in Arabidopsis.

Potassium deprivation leads to large reductions in plant growth and yields. How plants sense and transduce the stress signals initiated by potassium deprivation is poorly understood. Both ethylene production and the transcription of genes involved in ethylene biosynthesis increase when plants are deprived of potassium.

A role for phosphatidylinositol 3-phosphate in abscisic acid-induced reactive oxygen species generation in guard cells.

Guard cells generate reactive oxygen species (ROS) in response to abscisic acid (ABA), which leads to stomatal closing. The upstream steps of the ABA-induced ROS generation pathway remain largely unknown. In animal cells, ROS generation in neutrophils is activated by phosphatidylinositol 3-phosphate (PI3P).

Phosphatidylinositol 3- and 4-phosphate are required for normal stomatal movements.

Phosphatidylinositol (PI) metabolism plays a central role in signaling pathways in both animals and higher plants. Stomatal guard cells have been reported to contain PI 3-phosphate (PI3P) and PI 4-phosphate (PI4P), the products of PI 3-kinase (PI3K) and PI 4-kinase (PI4K) activities. In this study, we tested the roles of PI3P and PI4P in stomatal movements.