Emerging Research in Plant Cell Biology
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PLOS Biology: Strigolactone Can Promote or Inhibit Shoot Branching by Triggering Rapid Depletion of the Auxin Efflux Protein PIN1 from the Plasma Membrane

PLOS Biology: Strigolactone Can Promote or Inhibit Shoot Branching by Triggering Rapid Depletion of the Auxin Efflux Protein PIN1 from the Plasma Membrane | Emerging Research in Plant Cell Biology | Scoop.it
PLOS Biology is an open-access, peer-reviewed journal that features works of exceptional significance in all areas of biological science, from molecules to ecosystems, including works at the interface with other disciplines.
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Emerging Research in Plant Cell Biology
A science editor's take on what's new and interesting in the plant kingdom.
Curated by Jennifer Mach
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Rescooped by Jennifer Mach from Plant hormones and signaling peptides
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Hormone signalling: ABA has a breakdown

Hormone signalling: ABA has a breakdown | Emerging Research in Plant Cell Biology | Scoop.it
Abscisic acid (ABA) dynamically balances plant water use and availability. It is synthesized during water deficit and quickly catabolized into breakdown products previously thought to be largely inactive. New work demonstrates that phaseic acid, a major ABA catabolite, is a weak ABA receptor agonist with its own auxiliary role in water relations.

ABA plays a major role in controlling plant water use: its levels rise and fall in proportion to water deficit, coordinating transpiration and growth with environmental conditions1. ABA is synthesized in a series of well-characterized enzymatic steps from β-carotene and then catabolized through steps that are somewhat murkier2 (Fig. 1). The first catabolic step is hydroxylation by the CYP707A family of cytochrome P450s (CYPs). The hydroxylated products then isomerize into phaseic acid (PA) or neoPA, depending on the site of hydroxylation; this reaction occurs spontaneously in vitro and may not require an enzyme. In the next step, PA and neoPA are reduced to dihydrophaseic acid (DPA) and epi-DPA, respectively; but how this step is catalysed was unknown until now. In the final step, DPA and epi-DPA are converted to glucose esters by yet another unknown enzyme.

Via Christophe Jacquet
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Rescooped by Jennifer Mach from Plant roots and rhizosphere
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Frontiers in Plant Traffic and Transport: How membranes shape plant symbioses: signaling and transport in nodulation and arbuscular mycorrhiza (2012)

Frontiers in Plant Traffic and Transport: How membranes shape plant symbioses: signaling and transport in nodulation and arbuscular mycorrhiza (2012) | Emerging Research in Plant Cell Biology | Scoop.it

As sessile organisms that cannot evade adverse environmental conditions, plants have evolved various adaptive strategies to cope with environmental stresses. One of the most successful adaptations is the formation of symbiotic associations with beneficial microbes. In these mutualistic interactions the partners exchange essential nutrients and improve their resistance to biotic and abiotic stresses. In arbuscular mycorrhiza (AM) and in root nodule symbiosis (RNS), AM fungi and rhizobia, respectively, penetrate roots and accommodate within the cells of the plant host. In these endosymbiotic associations, both partners keep their plasma membranes intact and use them to control the bidirectional exchange of signaling molecules and nutrients. Intracellular accommodation requires the exchange of symbiotic signals and the reprogramming of both interacting partners. This involves fundamental changes at the level of gene expression and of the cytoskeleton, as well as of organelles such as plastids, endoplasmic reticulum (ER), and the central vacuole. Symbiotic cells are highly compartmentalized and have a complex membrane system specialized for the diverse functions in molecular communication and nutrient exchange. Here, we discuss the roles of the different cellular membrane systems and their symbiosis-related proteins in AM and RNS, and we review recent progress in the analysis of membrane proteins involved in endosymbiosis.


Via Kamoun Lab @ TSL, Alejandro Rojas, Emanuele Dal'Maso, Christophe Jacquet
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Genome-Wide Assessment of Efficiency and Specificity in CRISPR/Cas9 Mediated Multiple Site Targeting in Arabidopsis

Genome-Wide Assessment of Efficiency and Specificity in CRISPR/Cas9 Mediated Multiple Site Targeting in Arabidopsis | Emerging Research in Plant Cell Biology | Scoop.it
Simultaneous multiplex mutation of large gene families using Cas9 has the potential to revolutionize agriculture and plant sciences. The targeting of multiple genomic sites at once raises concerns about the efficiency and specificity in targeting. The model Arabidopsis thaliana is widely used in basic plant research. Previous work has suggested that the Cas9 off-target rate in Arabidopsis is undetectable. Here we use deep sequencing on pooled plants simultaneously targeting 14 distinct genomic loci to demonstrate that multiplex targeting in Arabidopsis is highly specific to on-target sites with no detectable off-target events. In addition, chromosomal translocations are extremely rare. The high specificity of Cas9 in Arabidopsis makes this a reliable method for clean mutant generation with no need to enhance specificity or adopt alternate Cas9 variants.
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Cotton plants export microRNAs to inhibit virulence gene expression in a fungal pathogen

Plant pathogenic fungi represent the largest group of disease-causing agents on crop plants, and are a constant and major threat to agriculture worldwide. Recent studies have shown that engineered production of RNA interference (RNAi)-inducing dsRNA in host plants can trigger specific fungal gene silencing and confer resistance to fungal pathogens1,​2,​3,​4,​5,​6,​7. Although these findings illustrate efficient uptake of host RNAi triggers by pathogenic fungi, it is unknown whether or not such an uptake mechanism has been evolved for a natural biological function in fungus–host interactions. Here, we show that in response to infection with Verticillium dahliae (a vascular fungal pathogen responsible for devastating wilt diseases in many crops) cotton plants increase production of microRNA 166 (miR166) and miR159 and export both to the fungal hyphae for specific silencing. We found that two V. dahliae genes encoding a Ca2+-dependent cysteine protease (Clp-1) and an isotrichodermin C-15 hydroxylase (HiC-15), and targeted by miR166 and miR159, respectively, are both essential for fungal virulence. Notably, V. dahliae strains expressing either Clp-1 or HiC-15 rendered resistant to the respective miRNA exhibited drastically enhanced virulence in cotton plants. Together, our findings identify a novel defence strategy of host plants by exporting specific miRNAs to induce cross-kingdom gene silencing in pathogenic fungi and confer disease resistance.Cotton plants export microRNAs to inhibit virulence gene expression in a fungal pathogen
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Rescooped by Jennifer Mach from legume symbiosis
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Interaction of Heterotrimeric G-Protein Components with Receptor-like Kinases in Plants: An Alternative to the Established Signaling Paradigm?

“Heterotrimeric G proteins comprising Gα, Gβ, and Gγ subunits (hereafter termed G proteins) mediate important signaling processes in all eukaryotes. As per the established paradigm, during resting phase the Gα is guanosine diphosphate (GDP)-bound and the three subunits form an inactive trimeric complex GDP⋅Gαβγ. Signal perception occurs at the G-protein coupled receptors (GPCRs), which act as guanine nucleotide exchange factors (GEFs) and facilitate the exchange of GDP for guanosine triphosphate (GTP) on Gα. GTP⋅Gα dissociates from the Gβγ dimer, and both these entities can interact with downstream effectors to transduce the signal. The intrinsic GTPase activity of Gα produces its GDP-bound form, which associates with the Gβγ dimer to reconstitute the inactive heterotrimer, making it available for the next round of activation (Figure 1). Proteins such as regulator of G-protein signaling (RGS) or phospholipases accelerate the inherent GTPase activity of Gα, causing a faster turnover of the cycle. Both the activation and deactivation of Gα are exquisitely controlled for persistent signaling (Offermanns, 2003).”
Via Jean-Michel Ané, Xiefang lab
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Rescooped by Jennifer Mach from The Plant Cell
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Dynamic interactions of Arabidopsis TEN1: stabilizing telomeres in response to heat stress ($)

Dynamic interactions of Arabidopsis TEN1: stabilizing telomeres in response to heat stress ($) | Emerging Research in Plant Cell Biology | Scoop.it

Lee, J.R., Xie, X., Yang, K., Zhang, J., Lee, S.Y. and Shippen, D.E. (2016). Dynamic interactions of Arabidopsis TEN1: stabilizing telomeres in response to heat stress. The Plant Cell. ; Advance Publication September 8, 2016; doi:10.1105/tpc.16.00408


Via Mary Williams
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Rescooped by Jennifer Mach from Microbes and plant immunity
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Bidirectional cross-kingdom RNAi and fungal uptake of external RNAs confer plant protection

Bidirectional cross-kingdom RNAi and fungal uptake of external RNAs confer plant protection | Emerging Research in Plant Cell Biology | Scoop.it
Aggressive fungal pathogens such as Botrytis and Verticillium spp. cause severe crop losses worldwide. We recently discovered that Botrytis cinerea delivers small RNAs (Bc–sRNAs) into plant cells to silence host immunity genes. Such sRNA effectors are mostly produced by Botrytis cinerea Dicer-like protein 1 (Bc-DCL1) and Bc-DCL2. Here we show that expressing sRNAs that target Bc-DCL1 and Bc-DCL2 in Arabidopsis and tomato silences Bc-DCL genes and attenuates fungal pathogenicity and growth, exemplifying bidirectional cross-kingdom RNAi and sRNA trafficking between plants and fungi. This strategy can be adapted to simultaneously control multiple fungal diseases. We also show that Botrytis can take up external sRNAs and double-stranded RNAs (dsRNAs). Applying sRNAs or dsRNAs that target Botrytis DCL1 and DCL2 genes on the surface of fruits, vegetables and flowers significantly inhibits grey mould disease. Such pathogen gene-targeting RNAs represent a new generation of environmentally friendly fungicides.

Via Giannis Stringlis
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Science: Special Issue on Plant Translational Biology

Science: Special Issue on Plant Translational Biology | Emerging Research in Plant Cell Biology | Scoop.it
Special Issue: Plant Translational Biology The new harvest BY PAMELA J. HINES, JOHN TRAVIS Translational plant science yields sustainable oils, pharmaceuticals, and proteins. 

The plant engineer BY ELIZABETH PENNISI Dan Voytas has worked tirelessly to make targeted genome editing of plants a reality. 

When is a GM plant not a GM plant? BY ELIZABETH PENNISI New genome-editing technologies have confused the regulatory picture for genetically modified plants. 

The nitrogen fix BY ERIK STOKSTAD Few projects in plant biotechnology are harder, or promise a greater payoff, than enabling crops to make their own nitrogen fertilizer. 

REVIEWS 
The plant lipidome in human and environmental health BY PATRICK J. HORN, CHRISTOPH BENNING 
Plant metabolism, the diverse chemistry set of the future BY ELEANORE T. WURTZEL, TONI M. KUTCHAN 
Plant-produced biopharmaceuticals: A case of technical developments driving clinical deployment BY GEORGE P. LOMONOSSOFF, MARC-ANDRÉ D’AOUST 
The next green movement: Plant biology for the environment and sustainability BY JOSEPH M. JEZ, SOON GOO LEE, ASHLEY M. SHERP
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Rescooped by Jennifer Mach from The Plant Cell
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In Brief. Swept Away: Protein Mobility in the Phloem

In Brief. Swept Away: Protein Mobility in the Phloem | Emerging Research in Plant Cell Biology | Scoop.it

In Brief. Swept Away: Protein Mobility in the Phloem

Jennifer Mach

Plant Cell 2016 tpc.16.00722; Advance Publication September 15, 2016; doi:10.1105/tpc.16.00722


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Rescooped by Jennifer Mach from Plant-microbe interaction
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The proteasome acts as a hub for plant immunity and is targeted by Pseudomonas type-III effectors

The proteasome acts as a hub for plant immunity and is targeted by Pseudomonas type-III effectors | Emerging Research in Plant Cell Biology | Scoop.it
Recent evidence suggests that the ubiquitin-proteasome system (UPS) is involved in several aspects of plant immunity and a range of plant pathogens subvert the UPS to enhance their virulence. Here we show that proteasome activity is strongly induced during basal defense in Arabidopsis. Mutant lines of the proteasome subunits RPT2a and RPN12a support increased bacterial growth of virulent Pseudomonas syringae pv. tomato DC3000 (Pst) and Pseudomonas syringae pv. maculicola ES4326. Both proteasome subunits are required for Pathogen-associated molecular patterns (PAMP)-triggered immunity (PTI) responses. Analysis of bacterial growth after a secondary infection of systemic leaves revealed that the establishment of systemic-acquired resistance (SAR) is impaired in proteasome mutants, suggesting that the proteasome also plays an important role in defense priming and SAR. In addition, we show that Pst inhibits proteasome activity in a type-III secretion dependent manner. A screen for type-III effector proteins from Pst for their ability to interfere with proteasome activity revealed HopM1, HopAO1, HopA1 and HopG1 as putative proteasome inhibitors. Biochemical characterization of HopM1 by mass-spectrometry indicates that HopM1 interacts with several E3 ubiquitin ligases and proteasome subunits. This supports the hypothesis that HopM1 associates with the proteasome leading to its inhibition. Thus, the proteasome is an essential component of PTI and SAR, which is targeted by multiple bacterial effectors.

Via Suayib Üstün
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Rescooped by Jennifer Mach from Plants and Microbes
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Plant Molecular Biology: Plant-Microbe Symbiotic Interactions (2016)

Plant Molecular Biology: Plant-Microbe Symbiotic Interactions (2016) | Emerging Research in Plant Cell Biology | Scoop.it
This special issue is dedicated to these topics, featuring research articles as well as review papers. Early communication, from chemotaxis, recognition of the microbes by the plant, effective colonization, and the plant genes necessary for positive response to the microorganisms are the focus of nine of the papers. Biotic stress tolerance conferred by plant-associated microorganisms against insects and microbial pathogens is covered in three papers. Increased tolerance to abiotic factors including salinity and limited nutrients as well as overall increased growth and health are the topics of three of the papers. Many of the authors included future perspectives on how to move this important research field forward. Information gained from plant–microbe interaction studies in native habitats may be especially relevant since the host plant and microorganisms have co-evolved with opportunities by the plant to select over time the most beneficial symbionts. Understanding the requirements for recruitment, recognition, colonization, and response will be essential if this knowledge is to be applied to commercial agriculture. Determination of the mechanisms by which microbiota impart tolerance to biotic and abiotic stress will enable optimization for improved plant health and growth under the increased challenges resulting from climate change.

Via Steve Marek, Kamoun Lab @ TSL
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Phosphoinositide signaling in plant development

Phosphoinositide signaling in plant development | Emerging Research in Plant Cell Biology | Scoop.it
The membranes of eukaryotic cells create hydrophobic barriers that control substance and information exchange between the inside and outside of cells and between cellular compartments. Besides their roles as membrane building blocks, some membrane lipids, such as phosphoinositides (PIs), also exert regulatory effects. Indeed, emerging evidence indicates that PIs play crucial roles in controlling polarity and growth in plants. Here, I highlight the key roles of PIs as important regulatory membrane lipids in plant development and function.
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Rescooped by Jennifer Mach from Plant Gene Seeker -PGS
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Reduced nighttime transpiration is a relevant breeding target for high water-use efficiency in grapevine

Reduced nighttime transpiration is a relevant breeding target for high water-use efficiency in grapevine | Emerging Research in Plant Cell Biology | Scoop.it

Breeding crops with more biomass produced per drop of water transpired is a key challenge in the context of climate change. However, the tight coupling between transpiration and carbon assimilation during the day makes it challenging to decrease water loss without altering photosynthesis and reducing crop yield. We tested whether reducing transpiration at night when photosynthesis is inactive could substantially reduce water loss without altering growth—a hypothesis that, to our knowledge, has never been genetically addressed in any species. By studying a whole progeny in grapevine, a major crop for drought-prone areas, we identified genomic regions where selection could be operated to reduce transpiration at night and maintain growth. This opens new horizons for breeding crops with higher water-use efficiency.


Via Andres Zurita
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Love the use of "drop" as the unit for water in the first sentence.
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Analysis of salicylic acid-dependent pathways in Arabidopsis thaliana following infection with Plasmodiophora brassicae and the influence of salicylic acid on disease - Lovelock - 2016 - Molecular ...

Analysis of salicylic acid-dependent pathways in Arabidopsis thaliana following infection with Plasmodiophora brassicae and the influence of salicylic acid on disease - Lovelock - 2016 - Molecular ... | Emerging Research in Plant Cell Biology | Scoop.it
Salicylic acid (SA) biosynthesis, the expression of SA-related genes and the effect of SA on the Arabidopsis–Plasmodiophora brassicae interaction were examined. Biochemical analyses revealed that, in P. brassicae-infected Arabidopsis, the majority of SA is synthesized from chorismate. Real-time monitored expression of a gene for isochorismate synthase was induced on infection. SA can be modified after accumulation, either by methylation, improving its mobility, or by glycosylation, as one possible reaction for inactivation. Quantitative reverse transcription-polymerase chain reaction (qPCR) confirmed the induction of an SA methyltransferase gene, whereas SA glucosyltransferase expression was not changed after infection. Col-0 wild-type (wt) did not provide a visible phenotypic resistance response, whereas the Arabidopsis mutant dnd1, which constitutively activates the immune system, showed reduced gall scores. As dnd1 showed control of the pathogen, exogenous SA was applied to Arabidopsis in order to test whether it could suppress clubroot. In wt, sid2 (SA biosynthesis), NahG (SA-deficient) and npr1 (SA signalling-impaired) mutants, SA treatment did not alter the gall score, but positively affected the shoot weight. This suggests that SA alone is not sufficient for Arabidopsis resistance against P. brassicae. Semi-quantitative PCR revealed that wt, cpr1, dnd1 and sid2 showed elevated PR-1 expression on P. brassicae and SA + P. brassicae inoculation at 2 and 3 weeks post-inoculation (wpi), whereas NahG and npr1 showed no expression. This work contributes to the understanding of SA involvement in the Arabidopsis–P. brassicae interaction.

Via Christophe Jacquet
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Brassinosteroid signaling and BRI1 dynamics went underground

Brassinosteroid signaling and BRI1 dynamics went underground | Emerging Research in Plant Cell Biology | Scoop.it
Brassinosteroids (BRs) are a group of steroid molecules perceived at the cell surface and that act as plant hormones. Since their discovery as crucial growth substances, BRs were mainly studied for their action in above ground organs and the BR signaling pathway was largely uncovered in the context of hypocotyl elongation. However, for the past two years, most of the exciting findings on BR signaling have been made using roots as a model. The Arabidopsis root is a system of choice for cell biology and allowed detailed characterization of BR perception at the cell membrane. In addition, a series of elegant articles dissected how BRs act in tissue specific manners to control root growth and development.
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Fast-Flowering Mini-Maize: Seed to Seed in 60 Days

Fast-Flowering Mini-Maize: Seed to Seed in 60 Days | Emerging Research in Plant Cell Biology | Scoop.it
Two lines of Zea mays were developed as a short-generation model for maize. The Fast-Flowering Mini-Maize (FFMM) lines A and B are robust inbred lines with a significantly shorter generation time, much smaller stature, and better greenhouse adaptation than traditional maize varieties. Five generations a year are typical. FFMM is the result of a modified double-cross hybrid between four fast-flowering lines: Neuffer’s Early ACR (full color), Alexander’s Early Early Synthetic, Tom Thumb Popcorn, and Gaspe Flint, followed by selection for early flowering and desirable morphology throughout an 11-generation selfing regime. Lines A and B were derived from different progeny of the initial hybrid, and crosses between Mini-Maize A and B exhibit heterosis. The ancestry of each genomic region of Mini-Maize A and B was inferred from the four founder populations using genotyping by sequencing. Other genetic and genomic tools for these lines include karyotypes for both lines A and B, kernel genetic markers y1 (white endosperm) and R1-scm2 (purple endosperm and embryo) introgressed into Mini-Maize A, and ∼24× whole-genome resequencing data for Mini-Maize A.
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Rescooped by Jennifer Mach from microbial pathogenesis and plant immunity
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The Plant Microbiota: Systems-Level Insights and Perspectives - Annual Review of Genetics, 50(1):

The Plant Microbiota: Systems-Level Insights and Perspectives - Annual Review of Genetics, 50(1): | Emerging Research in Plant Cell Biology | Scoop.it

Via Tatsuya Nobori, Jim Alfano
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COOLAIR Antisense RNAs Form Evolutionarily Conserved Elaborate Secondary Structures

COOLAIR Antisense RNAs Form Evolutionarily Conserved Elaborate Secondary Structures | Emerging Research in Plant Cell Biology | Scoop.it
There is considerable debate about the functionality of long non-coding RNAs (lncRNAs). Lack of sequence conservation has been used to argue against functional relevance. We investigated antisense lncRNAs, called COOLAIR, at the A. thaliana FLC locus and experimentally determined their secondary structure. The major COOLAIR variants are highly structured, organized by exon. The distally polyadenylated transcript has a complex multi-domain structure, altered by a single non-coding SNP defining a functionally distinct A. thaliana FLC haplotype. The A. thaliana COOLAIR secondary structure was used to predict COOLAIR exons in evolutionarily divergent Brassicaceae species. These predictions were validated through chemical probing and cloning. Despite the relatively low nucleotide sequence identity, the structures, including multi-helix junctions, show remarkable evolutionary conservation. In a number of places, the structure is conserved through covariation of a non-contiguous DNA sequence. This structural conservation supports a functional role for COOLAIR transcripts rather than, or in addition to, antisense transcription.
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Rescooped by Jennifer Mach from Plant roots and rhizosphere
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Cytokinins influence root gravitropism via differential regulation of auxin transporter expression and localization in Arabidopsis - Pernisova - 2016 - New Phytologist -

Cytokinins influence root gravitropism via differential regulation of auxin transporter expression and localization in Arabidopsis - Pernisova - 2016 - New Phytologist - | Emerging Research in Plant Cell Biology | Scoop.it
Redirection of intercellular auxin fluxes via relocalization of the PIN-FORMED 3 (PIN3) and PIN7 auxin efflux carriers has been suggested to be necessary for the root gravitropic response. Cytokinins have also been proposed to play a role in controlling root gravitropism, but conclusive evidence is lacking.
We present a detailed study of the dynamics of root bending early after gravistimulation, which revealed a delayed gravitropic response in transgenic lines with depleted endogenous cytokinins (Pro35S:AtCKX) and cytokinin signaling mutants. Pro35S:AtCKX lines, as well as a cytokinin receptor mutant ahk3, showed aberrations in the auxin response distribution in columella cells consistent with defects in the auxin transport machinery.
Using in vivo real-time imaging of PIN3-GFP and PIN7-GFP in AtCKX3 overexpression and ahk3 backgrounds, we observed wild-type-like relocalization of PIN proteins in the columella early after gravistimulation, with gravity-induced relocalization of PIN7 faster than that of PIN3. Nonetheless, the cellular distribution of PIN3 and PIN7 and expression of PIN7 and the auxin influx carrier AUX1 was affected in AtCKX overexpression lines.
Based on the retained cytokinin sensitivity in pin3 pin4 pin7 mutant, we propose the AUX1-mediated auxin transport rather than columella-located PIN proteins as a target of endogenous cytokinins in the control of root gravitropism.

Via Christophe Jacquet
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Cellulose synthase complexes act in a concerted fashion to synthesize highly aggregated cellulose in secondary cell walls of plants

Cellulose synthase complexes act in a concerted fashion to synthesize highly aggregated cellulose in secondary cell walls of plants | Emerging Research in Plant Cell Biology | Scoop.it

Cellulose, often touted as the most abundant biopolymer on Earth, is a critical component of the plant cell wall and is synthesized by plasma membrane-spanning cellulose synthase (CESA) enzymes, which in plants are organized into rosette-like CESA complexes (CSCs). Plants construct two types of cell walls, primary cell walls (PCWs) and secondary cell walls (SCWs), which differ in composition, structure, and purpose. Cellulose in PCWs and SCWs is chemically identical but has different physical characteristics. During PCW synthesis, multiple dispersed CSCs move along a shared linear track in opposing directions while synthesizing cellulose microfibrils with low aggregation. In contrast, during SCW synthesis, we observed swaths of densely arranged CSCs that moved in the same direction along tracks while synthesizing cellulose microfibrils that became highly aggregated. Our data support a model in which distinct spatiotemporal features of active CSCs during PCW and SCW synthesis contribute to the formation of cellulose with distinct structure and organization in PCWs and SCWs of Arabidopsis thaliana. This study provides a foundation for understanding differences in the formation, structure, and organization of cellulose in PCWs and SCWs.

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GAD1 Encodes a Secreted Peptide That Regulates Grain Number, Grain Length and Awn Development in Rice Domestication

GAD1 Encodes a Secreted Peptide That Regulates Grain Number, Grain Length and Awn Development in Rice Domestication | Emerging Research in Plant Cell Biology | Scoop.it

GAD1 Encodes a Secreted Peptide That Regulates Grain Number, Grain Length and Awn Development in Rice Domestication

Jing Jin, Lei Hua, Zuofeng Zhu, Lubin Tan, Xinhui Zhao, Weifeng Zhang, Fengxia Liu, Yongcai Fu, Hongwei Cai, Xianyou Sun, Ping Gu, Daoxin Xie, and Chuanqing Sun

Plant Cell 2016 tpc.16.00379; Advance Publication September 15, 2016; doi:10.1105/tpc.16.00379 OPEN


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Rescooped by Jennifer Mach from Plant & Evolution
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Gα and regulator of G-protein signaling (RGS) protein pairs in plant evolution

Gα and regulator of G-protein signaling (RGS) protein pairs in plant evolution | Emerging Research in Plant Cell Biology | Scoop.it
Signaling pathways regulated by heterotrimeric G-proteins exist in all eukaryotes. The regulator of G-protein signaling (RGS) proteins are key interactors and critical modulators of the Gα protein of the heterotrimer. However, while G-proteins are widespread in plants, RGS proteins have been reported to be missing from the entire monocot lineage, with two exceptions. A single amino acid substitution-based adaptive coevolution of the Gα:RGS proteins was proposed to enable the loss of RGS in monocots. We used a combination of evolutionary and biochemical analyses and homology modeling of the Gα and RGS proteins to address their expansion and its potential effects on the G-protein cycle in plants. Our results show that RGS proteins are widely distributed in the monocot lineage, despite their frequent loss. There is no support for the adaptive coevolution of the Gα:RGS protein pair based on single amino acid substitutions. RGS proteins interact with, and affect the activity of, Gα proteins from species with or without endogenous RGS. This cross-functional compatibility expands between the metazoan and plant kingdoms, illustrating striking conservation of their interaction interface. We propose that additional proteins or alternative mechanisms may exist which compensate for the loss of RGS in certain plant species.

Via Pierre-Marc Delaux
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New Phytologist: Nine things to know about elicitins (2016)

New Phytologist: Nine things to know about elicitins (2016) | Emerging Research in Plant Cell Biology | Scoop.it

Elicitins are structurally conserved extracellular proteins in Phytophthora and Pythium oomycete pathogen species. They were first described in the late 1980s as abundant proteins in Phytophthora culture filtrates that have the capacity to elicit hypersensitive (HR) cell death and disease resistance in tobacco. Later, they became well-established as having features of microbe-associated molecular patterns (MAMPs) and to elicit defences in a variety of plant species. Research on elicitins culminated in the recent cloning of the elicitin response (ELR) cell surface receptor-like protein, from the wild potato Solanum microdontum, which mediates response to a broad range of elicitins. In this review, we provide an overview on elicitins and the plant responses they elicit. We summarize the state of the art by describing what we consider to be the nine most important features of elicitin biology.


Via Kamoun Lab @ TSL
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Rescooped by Jennifer Mach from Plant pathogenic fungi
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RNA ‘Information Warfare’ in Pathogenic and Mutualistic Interactions

RNA ‘Information Warfare’ in Pathogenic and Mutualistic Interactions | Emerging Research in Plant Cell Biology | Scoop.it
Regulatory non-coding RNAs are emerging as key players in host–pathogen interactions. Small RNAs such as microRNAs are implicated in regulating plant transcripts involved in immunity and defence. Surprisingly, RNAs with silencing properties can be translocated from plant hosts to various invading pathogens and pests. Small RNAs are now confirmed virulence factors, with the first report of fungal RNAs that travel to host cells and hijack post-transcriptional regulatory machinery to suppress host defence. Here, we argue that trans-organism movement of RNAs represents a common mechanism of control in diverse interactions between plants and other eukaryotes. We suggest that extracellular vesicles are the key to such RNA movement events. Plant pathosystems serve as excellent experimental models to dissect RNA ‘information warfare’ and other RNA-mediated interactions.

Trends
Plant–pathogen interactions have undergone a paradigm shift, with the observation that silencing, non-coding RNAs move between host and pathogen, and vice versa.

So far, only one unequivocal natural example of this phenomenon has been exposed, where RNAs from Botrytis cinerea (grey mould) move into host plants. There, they ‘hijack’ host silencing machinery to downregulate transcripts involved in defence and immunity.

Similar RNA-based phenomena in interactions between animals and their microbial pathogens suggest that this mechanism is a commonality between infections in widely divergent taxa.

As well as a potent tool for developing new crops with increased disease resistance, studies of RNA traffic between plants and their symbionts will serve as models for other disease interactions.

Via Steve Marek
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New evidence for grain specific C4 photosynthesis in wheat

New evidence for grain specific C4 photosynthesis in wheat | Emerging Research in Plant Cell Biology | Scoop.it
The C4 photosynthetic pathway evolved to allow efficient CO2 capture by plants where effective carbon supply may be limiting as in hot or dry environments, explaining the high growth rates of C4 plants such as maize.
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