Table of Contents
IN BRIEF
RESEARCH ARTICLES
- Global Epigenetic and Transcriptional Trends among Two Rice Subspecies and Their Reciprocal Hybrids
This work examines the molecular basis of heterosis by comprehensively describing the epigenetic modifications and transcriptional output, including both mRNA and small RNAs, of two rice subspecies and their reciprocal hybrids.
- Cooperation of Multiple Chromatin Modifications Can Generate Unanticipated Stability of Epigenetic States in Arabidopsis
Make assurance double sure: Two chromatin modifications join forces to create a double lock and need to be removed simultaneously to reactivate a heritable epiallele originating from polyploid Arabidopsis.
- Bifurcation and Enhancement of Autonomous-Nonautonomous Retrotransposon Partnership through LTR Swapping in Soybean
This work demonstrates that region-specific interelement recombinational exchange, behind natural selection, plays a primary role in maintaining preexisting partnership and establishing new partnership between nonautonomous and autonomous long terminal repeat retrotransposons in soybean.
- BLADE-ON-PETIOLE1 Coordinates Organ Determinacy and Axial Polarity in Arabidopsis by Directly Activating ASYMMETRIC LEAVES2
This study shows that BOP1 and BOP2 regulate key organogenic events in the proximal region of cotyledon and leaf primordia. Direct activation of AS2 transcription by BOP1 and BOP2 is found to be required for KNOX1 gene repression at the leaf base and may represent a conserved mechanism for coordinating leaf morphogenesis with patterning along the adaxial-abaxial and the proximal-distal axes.
- The Plastid Isoform of Triose Phosphate Isomerase Is Required for the Postgerminative Transition from Heterotrophic to Autotrophic Growth in Arabidopsis
An Arabidopsis plastid triose phosphate isomerase mutant was reduced in transcript, protein, and activity, resulting in a severely stunted plant at the transition from heterotrophic to autotrophic growth. Accumulation of dihydroxyacetone phosphate and methylglyoxal to toxic levels is proposed as a cause of this phenotype, as exogenous application of these metabolites mimicked the phenotype.
- The ABORTED MICROSPORES Regulatory Network Is Required for Postmeiotic Male Reproductive Development in Arabidopsis thaliana
This study identifies targets and interacting factors of an Arabidopsis basic helix-loop-helix protein, ABORTED MICROSPORES (AMS), which is known to be required for pollen development. AMS is found to regulate the expression of several genes involved in metabolism and pollen wall deposition.
- Arabidopsis CULLIN4-Damaged DNA Binding Protein 1 Interacts with CONSTITUTIVELY PHOTOMORPHOGENIC1-SUPPRESSOR OF PHYA Complexes to Regulate Photomorphogenesis and Flowering Time
CUL4-DDB1 associates with COP1-SPA complexes via its linker protein DDB1 to regulate photomorphogenesis and possibly also flowering time under short-day conditions. The CUL4-DDB1-COP1-SPA supercomplex may represent a novel group of E3 ligases that functions independently of the CDD complex.
- The RAD23 Family Provides an Essential Connection between the 26S Proteasome and Ubiquitylated Proteins in Arabidopsis
This study describes the collection of UBL/UBA domain proteins in Arabidopsis that participate in the ubiquitin/26S proteasome system, with a focus on the RAD23 family. The data point to a specific role for RAD23s in plants and suggest that the four isoforms have both redundant and unique roles in Arabidopsis development by helping shuttle ubiquitin conjugates to the 26S proteasome.
- Auxin-Mediated Ribosomal Biogenesis Regulates Vacuolar Trafficking in Arabidopsis
This study describes the function of RPL4A, a ribosomal protein. It finds a link between ribosomal biogenesis and vacuolar protein sorting and provides insights into the auxin-mediated regulation of vacuolar trafficking in metabolically active tissues.
- Loss-of-Function Mutations of Retromer Large Subunit Genes Suppress the Phenotype of an Arabidopsis zig Mutant That Lacks Qb-SNARE VTI11
This work shows that loss-of-function mutants of retromer large subunit genes ZIP3/VPS35a, VPS29, and VPS26a partially suppressed the defects in morphology and gravitropism of zig mutants. By contrast, mutations of the paralogous genes VPS35b, VPS35c, and VPS26b do not suppress zig. Functional differences among these paralogous genes suggest that VPS35A function differs from that of VPS35B or VPS35C.
- Cytochrome P450 Family Member CYP704B2 Catalyzes the ω -Hydroxylation of Fatty Acids and Is Required for Anther Cutin Biosynthesis and Pollen Exine Formation in Rice
This work finds that a fatty acid ω -hydroxylation pathway in rice that relies on an ancient cytochrome P450 subfamily is essential for the formation of both anther cuticle and pollen exine during plant male reproductive and spore development.
- The γ -Tubulin Complex Protein GCP4 Is Required for Organizing Functional Microtubule Arrays in Arabidopsis thaliana
This study demonstrates that γ -Tubulin Complex Protein 4 plays a crucial role in γ -tubulin–mediated microtubule nucleation and organization during cell division and morphogenesis in Arabidopsis.
- A Stromal Heat Shock Protein 70 System Functions in Protein Import into Chloroplasts in the Moss Physcomitrella patens
This work uses reverse genetic and biochemical approaches to provide evidence supporting the hypothesis that an Hsp70 system plays a heretofore unrecognized role in chloroplast protein import.
- An Arabidopsis Mutant with High Cyclic Electron Flow around Photosystem I (hcef) Involving the NADPH Dehydrogenase Complex
Analysis of a mutant, hcef1, in chloroplast fructose-1,6-bisphosphatase demonstrates that C3 plants are capable of high steady state fluxes of cyclic electron flow around photosystem I, which is important for chloroplast energy balance and involves the NAD(P)H dehydrogenase, but not the PGR5, pathway.
- MRL1, a Conserved Pentatricopeptide Repeat Protein, Is Required for Stabilization of rbcL mRNA in Chlamydomonas and Arabidopsis
The expression of the chloroplast genome requires specialized proteins that are coded in the nucleus and imported into the organelle. We have identified such a protein that binds the leading end of the mRNA for the most abundant chloroplast enzyme. The function of this novel stabilization factor is conserved from green algae to land plants.
- The Arabidopsis Prohibitin Gene PHB3 Functions in Nitric Oxide–Mediated Responses and in Hydrogen Peroxide–Induced Nitric Oxide Accumulation
Nitric oxide serves as a signal in biotic and abiotic stress responses in plants, yet little is known about its metabolism under aerobic conditions. Using a genetic screen to isolate mutants defective in nitric oxide accumulation, a prohibitin gene was identified that regulates nitric oxide levels and affects stress responses that use nitric oxide signaling.
- Tomato 14-3-3 Protein 7 Positively Regulates Immunity-Associated Programmed Cell Death by Enhancing Protein Abundance and Signaling Ability of MAPKKK α
14-3-3 proteins bind and regulate phosphorylated client proteins involved in diverse biological processes in eukaryotic organisms. This work reports that a tomato 14-3-3 protein regulates plant immunity by altering the abundance of a positive regulator of cell death.
- Jasmonate and ppHsystemin Regulate Key Malonylation Steps in the Biosynthesis of 17-Hydroxygeranyllinalool Diterpene Glycosides, an Abundant and Effective Direct Defense against Herbivores in Nicotiana attenuata
This study describes the biosynthetic dynamics of diterpene glycosides abundant in a wild tobacco and highlights glycosylation and malonylation as key biosynthetic steps producing the diversity of compounds observed. It shows that plants silenced in diterpene glycoside production suffered more damage from herbivores in their natural habitat and were higher-quality food for a specialist herbivore.
