Table of Contents
IN BRIEF
RESEARCH ARTICLES
- FAR-RED ELONGATED HYPOCOTYL1 and FHY1-LIKE Associate with the Arabidopsis Transcription Factors LAF1 and HFR1 to Transmit Phytochrome A Signals for Inhibition of Hypocotyl Elongation
This study uses genetic and biochemical analyses to show that the homologous proteins FHY1 and FHL are required for the formation of multimeric signaling complexes, including phytochrome A and downstream transcription factors in response to different FRc fluences. Such photoreceptor/transcription factor complexes likely mediate molecular and physiological responses triggered by phyA.
- A Role for Arabidopsis PUCHI in Floral Meristem Identity and Bract Suppression
Acquisition of flower identity in Arabidopsis is associated with the switch from an indeterminate to a determinate growth pattern and suppression of a subtending leaf called a bract. It is shown that the AP2/EREBP gene PUCHI, together with the NPR1-like signaling genes BOP1 and BOP2, are required for these processes, possibly through position-specific activation of the floral regulators LFY and AP1.
- The NGATHA Distal Organ Development Genes Are Essential for Style Specification in Arabidopsis
A group of B3 transcription factors that function in the distal portions of all leaves and floral organs has been co-opted to specify the style of the Arabidopsis gynoecium. This works finds that these genes likely are activated by an auxin threshold signal and negatively regulate ovary factors while promoting style gene expression and auxin biosynthesis in a positive feedback loop.
- The NGATHA Genes Direct Style Development in the Arabidopsis Gynoecium
The B3 gene family encodes plant-specific transcription factors with a diverse range of functions in Arabidopsis. Here, a small subfamily of highly related and redundant B3 genes, the NGATHA genes, are shown to be essential for proper development of the style in Arabidopsis carpels, in part by directing YUCCA-mediated auxin synthesis in this domain.
- Chromatin and DNA Modifications in the Opaque2-Mediated Regulation of Gene Transcription during Maize Endosperm Development
This work shows that transcription mediated by the endosperm-specific transcriptional activator Opaque2 (O2) is associated with tissue- and developmental-related changes in chromatin modifications and cytosine methylation at its targets. Different targets show different O2 requirements, suggesting gene-specific interaction of O2 with chromatin modifying mechanisms.
- Regulatory Features Underlying Pollination-Dependent and -Independent Tomato Fruit Set Revealed by Transcript and Primary Metabolite Profiling
This work examines the role of the transcription factor IAA9, the indole-3-acetic acid–induced protein, in early fruit development and pollination-independent fruit set. IAA9 expression is downregulated after pollination, and plants with reduced IAA9 expression produce fruit in the absence of pollination; transcript and metabolic profiling of these plants reveals signaling and regulatory changes.
- Gibberellin Modulates Anther Development in Rice via the Transcriptional Regulation of GAMYB
The authors examine the physiological function of gibberellin (GA) in anther development. Cytological observations and microarray analysis of GA-related mutants reveal that GA is involved in exine formation by directing the expression of the lipid metabolic genes, cytochrome P450 hydroxylase CYP703A3 and β-ketoacyl reductase.
- The Ethylene Receptor ETR2 Delays Floral Transition and Affects Starch Accumulation in Rice
This work shows that a subfamily II ethylene receptor ETR2 in rice is a Ser/Thr kinase and not a His kinase. Overexpression or suppression of ETR2 affected flowering, seed-setting, and thousand-seed weight in rice, providing important clues for improving yield-related traits through the manipulation of ethylene signaling.
- Arabidopsis ASA1 Is Important for Jasmonate-Mediated Regulation of Auxin Biosynthesis and Transport during Lateral Root Formation
This study shows that jasmonate upregulates auxin synthesis through transcriptional activation of ASA1 and also attenuates auxin transport in an ASA1-dependent manner. These aspects of jasmonate actions represent fine-tuned regulation of local auxin accumulation in the root basal meristem that is critical for lateral root formation.
- DWARF27, an Iron-Containing Protein Required for the Biosynthesis of Strigolactones, Regulates Rice Tiller Bud Outgrowth
It is shown here that a novel rice iron-containing protein is involved in the biosynthesis of strigolactones and is essential for the development of rice tillers.
- Calcium Spiking Patterns and the Role of the Calcium/Calmodulin-Dependent Kinase CCaMK in Lateral Root Base Nodulation of Sesbania rostrata
Rhizobia invade Sesbania rostrata intracellularly under dry conditions and intercellularly under humid conditions. It is shown that entry of rhizobia into root hairs is accompanied by specific calcium spiking, whereas intercellular invasion is independent of calcium spiking. Alternative signaling for intercellular invasion may have evolved because calcium spiking patterns change upon waterlogging.
- Remorin, a Solanaceae Protein Resident in Membrane Rafts and Plasmodesmata, Impairs Potato virus X Movement
This work shows that remorin has the biochemical properties of a lipid raft protein and localizes in plasma membrane patches and plasmodesmata. The results unify biochemical, localization, and functional features predicted for plasma membrane microdomains and indicate that plasmodesmata share some properties of lipid rafts.
- Local Differentiation of Sugar Donor Specificity of Flavonoid Glycosyltransferase in Lamiales
Certain plant lineages increase their environmental fitness by producing specialized metabolites via the acquisition of novel enzyme functions. Here it is shown that flavonoid glucuronosyltransferase is responsible for a specialized metabolite of Lamiales and may have differentiated from parental glucosyltransferase by acquisition of an Arg residue required for the sugar donor specificity change.
- Association Genetics Reveals Three Novel Avirulence Genes from the Rice Blast Fungal Pathogen Magnaporthe oryzae
This work uses genome resequencing, large-scale association genetics, and in vivo functional complementation to identify avirulence proteins AVR-Pia, AVR-Pii, and AVR-Pik/km/kp from among a large set of candidate secreted proteins from the major rice pathogen Magnaporthe oryzae.
- Dynamic Behavior of Arabidopsis eIF4A-III, Putative Core Protein of Exon Junction Complex: Fast Relocation to Nucleolus and Splicing Speckles under Hypoxia
This study examines Arabidopsis eIF4A-III, showing its dynamic localization to the nucleolus and speckles during hypoxia and its physical interaction and colocalization with other members of the exon junction complex.
- Phosphorylation of SOS3-LIKE CALCIUM BINDING PROTEIN8 by SOS2 Protein Kinase Stabilizes Their Protein Complex and Regulates Salt Tolerance in Arabidopsis
This work shows that C-terminal phosphorylation of SOS3-LIKE CALCIUM BINDING PROTEIN8 (SCaBP8) by SALT OVERLY SENSITIVE2 (SOS2) is required for its function in salt tolerance. This phosphorylation occurs at the cell membrane in response to salt stress and stabilizes the SOS2-SCaBP8 protein complex.
