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A cytochrome P450 regulates a domestication trait in cultivated tomato

Domestication of crop plants had effects on human lifestyle and agriculture. However, little is known about the underlying molecular mechanisms accompanying the changes in fruit appearance as a consequence of selection by early farmers. We report the fine mapping and cloning of a tomato (Solanum lycopersicum) fruit mass gene encoding the ortholog of KLUH, SlKLUH, a P450 enzyme of the CYP78A subfamily. The increase in fruit mass is predominantly the result of enlarged pericarp and septum tissues caused by increased cell number in the large fruited lines. SlKLUH also modulates plant architecture by regulating number and length of the side shoots, and ripening time, and these effects are particularly strong in plants that transgenically down-regulate SlKLUH expression carrying fruits of a dramatically reduced mass. Association mapping followed by segregation analyses revealed that a single nucleotide polymorphism in the promoter of the gene is highly associated with fruit mass. This single polymorphism may potentially underlie a regulatory mutation resulting in increased SlKLUH expression concomitant with increased fruit mass. Our findings suggest that the allele giving rise to large fruit arose in the early domesticates of tomato and becoming progressively more abundant upon further selections. We also detected association of fruit weight with CaKLUH in chile pepper (Capsicum annuum) suggesting that selection of the orthologous gene may have occurred independently in a separate domestication event. Altogether, our findings shed light on the molecular basis of fruit mass, a key domestication trait in tomato and other fruit and vegetable crops.

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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.
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Dietary delivery: a new avenue for microRNA therapeutics?: Trends in Biotechnology

Many people carefully monitor their food choices, adhering to the philosophy that ‘you are what you eat’. Recent research adds a new wrinkle to that old adage, suggesting that dietary small RNAs (sRNAs) can control the gene expression of the consumer and may provide an effective, noninvasive, and inexpensive therapy for many human diseases.
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Rescooped by Jennifer Mach from Plant immunity and legume symbiosis
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Cues from chewing insects — the intersection of DAMPs, HAMPs, MAMPs and effectors

Cues from chewing insects — the intersection of DAMPs, HAMPs, MAMPs and effectors | Emerging Research in Plant Cell Biology | Scoop.it

Highlights•

Upon feeding, herbivores secrete saliva, regurgitant and frass that come in contact with the plant.

Herbivore's gut symbionts can also be released during feeding and recognized by the plant.

The composition of these secretions and gut microbial community is dependent upon their host plant and the herbivore.

Cues present in herbivore secretions are recognized by plants to trigger defense responses.

Some of these cues can act as effectors or elicitors in a context dependent manner.

Chewing herbivores cause massive damage when crushing plant tissues with their mandibles, thus releasing a vast array of cues that may be perceived by the plant to mobilize defenses. Besides releasing damage cues in wounded tissues, herbivores deposit abundant cues from their saliva, regurgitant and feces that trigger herbivore specific responses in plants. Herbivores can manipulate the perception mechanisms and defense signals to suppress plant defenses by secreting effectors and/or by exploiting their associated oral microbes. Recent studies indicate that both the composition of herbivore cues and the plant's ability to recognize them are highly dependent upon the specific plant–herbivore system. There is a growing amount of work on identifying herbivore elicitors and effectors, but the most significant bottleneck in the discipline is the identification and characterization of plant receptors that perceive these herbivore-specific cues.

 

 


Via Christophe Jacquet
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A Recently Evolved Alternative Splice Site in the BRANCHED1a Gene Controls Potato Plant Architecture: Current Biology

A Recently Evolved Alternative Splice Site in the BRANCHED1a Gene Controls Potato Plant Architecture: Current Biology | Emerging Research in Plant Cell Biology | Scoop.it
•In the Solanum clade, an alternative splice site evolved in the BRC1a gene•Alternative splicing of potato BRC1a renders two proteins with antagonistic functions•BRC1aLong isoform is a transcription factor that prevents shoot and stolon branching•BRC1aShort isoform interacts with and limits BRC1aLong nuclear targeting

 

Summary

Amplification and diversification of transcriptional regulators that control development is a driving force of morphological evolution. A major source of protein diversity is alternative splicing, which leads to the generation of different isoforms from a single gene. The mechanisms and timing of intron evolution nonetheless remain unclear, and the functions of alternative splicing-generated protein isoforms are rarely studied. In Solanum tuberosum, the BRANCHED1a (BRC1a) gene encodes a TCP transcription factor that controls lateral shoot outgrowth. Here, we report the recent evolution in Solanum of an alternative splice site in BRC1a that leads to the generation of two BRC1a protein isoforms with distinct C-terminal regions, BRC1aLong and BRC1aShort, encoded by unspliced and spliced mRNA, respectively. The BRC1aLong C-terminal region has a strong activation domain, whereas that of BRC1aS lacks an activation domain and is predicted to form an amphipathic helix, the H domain, which prevents protein nuclear targeting. BRC1aShort is thus mainly cytoplasmic, while BRC1aLong is mainly nuclear. BRC1aLong functions as a transcriptional activator, whereas BRC1aShort appears to have no transcriptional activity. Moreover, BRC1aShort can heterodimerize with BRC1aLong and act as a dominant-negative factor; it increases BRC1aLong concentration in cytoplasm and reduces its transcriptional activity. This alternative splicing mechanism is regulated by hormones and external stimuli that control branching. The evolution of a new alternative splicing site and a novel protein domain in Solanum BRC1a led to a multi-level mechanism of post-transcriptional and post-translational BRC1a regulation that effectively modulates its branch suppressing activity in response to environmental and endogenous cues.

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The first crop plant genetically engineered to release an insect pheromone for defence

The first crop plant genetically engineered to release an insect pheromone for defence | Emerging Research in Plant Cell Biology | Scoop.it

Insect pheromones offer potential for managing pests of crop plants. Volatility and instability are problems for deployment in agriculture but could be solved by expressing genes for the biosynthesis of pheromones in the crop plants. This has now been achieved by genetically engineering a hexaploid variety of wheat to release (E)-β-farnesene (Eβf), the alarm pheromone for many pest aphids, using a synthetic gene based on a sequence from peppermint with a plastid targeting amino acid sequence, with or without a gene for biosynthesis of the precursor farnesyl diphosphate. Pure Eβf was produced in stably transformed wheat lines with no other detectable phenotype but requiring targeting of the gene produced to the plastid. In laboratory behavioural assays, three species of cereal aphids were repelled and foraging was increased for a parasitic natural enemy. Although these studies show considerable potential for aphid control, field trials employing the single and double constructs showed no reduction in aphids or increase in parasitism. Insect numbers were low and climatic conditions erratic suggesting the need for further trials or a closer imitation, in the plant, of alarm pheromone release.

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PNAS: The butterfly plant arms-race escalated by gene and genome duplications (2015)

PNAS: The butterfly plant arms-race escalated by gene and genome duplications (2015) | Emerging Research in Plant Cell Biology | Scoop.it

Coevolutionary interactions are thought to have spurred the evolution of key innovations and driven the diversification of much of life on Earth. However, the genetic and evolutionary basis of the innovations that facilitate such interactions remains poorly understood. We examined the coevolutionary interactions between plants (Brassicales) and butterflies (Pieridae), and uncovered evidence for an escalating evolutionary arms-race. Although gradual changes in trait complexity appear to have been facilitated by allelic turnover, key innovations are associated with gene and genome duplications. Furthermore, we show that the origins of both chemical defenses and of molecular counter adaptations were associated with shifts in diversification rates during the arms-race. These findings provide an important connection between the origins of biodiversity, coevolution, and the role of gene and genome duplications as a substrate for novel traits.


See also blog post https://decodingscience.missouri.edu/2015/06/22/scientists-uncover-how-caterpillars-created-condiments/


Via Kamoun Lab @ TSL, Mary Williams
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Repression of microRNA biogenesis by silencing of OsDCL1 activates the basal resistance to Magnaporthe oryzae in rice

Repression of microRNA biogenesis by silencing of OsDCL1 activates the basal resistance to Magnaporthe oryzae in rice | Emerging Research in Plant Cell Biology | Scoop.it
Highlights



OsDCL1 RNAi lines showed enhanced resistance to rice blast.


A negative feedback loop between miR162a and OsDCL1 was identified.


Differentially expressed miRNAs responsive to rice blast infection were identified.


PR and PTI responsive genes were constitutively activated in OsDCL1 RNAi lines.

Abstract

The RNaseIII enzyme Dicer-like 1 (DCL1) processes the microRNA biogenesis and plays a determinant role in plant development. In this study, we reported the function of OsDCL1 in the immunity to rice blast, the devastating disease caused by the fungal pathogen, Magnaporthe oryzae. Expression profiling demonstrated that different OsDCLs responded dynamically and OsDCL1 reduced its expression upon the challenge of rice blast pathogen. In contrast, miR162a predicted to target OsDCL1 increased its expression, implying a negative feedback loop between OsDCL1 and miR162a in rice. In addition to developmental defects, the OsDCL1-silencing mutants showed enhanced resistance to virulent rice blast strains in a non-race specific manner. Accumulation of hydrogen peroxide and cell death were observed in the contact cells with infectious hyphae, revealing that silencing of OsDCL1 activated cellular defense responses. In OsDCL1 RNAi lines, 12 differentially expressed miRNAs were identified, of which 5 and 7 were down- and up-regulated, respectively, indicating that miRNAs responded dynamically in the interaction between rice and rice blast. Moreover, silencing of OsDCL1 activated the constitutive expression of defense related genes. Taken together, our results indicate that rice is capable of activating basal resistance against rice blast by perturbing OsDCL1-dependent miRNA biogenesis pathway.

Via Christophe Jacquet
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Rescooped by Jennifer Mach from MycorWeb Plant-Microbe Interactions
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Frontiers | Does plant immunity play a critical role during initiation of the legume-rhizobium symbiosis? | Plant-Microbe Interaction

Frontiers | Does plant immunity play a critical role during initiation of the legume-rhizobium symbiosis? | Plant-Microbe Interaction | Emerging Research in Plant Cell Biology | Scoop.it
Plants are exposed to many different microbes in their habitats. These microbes may be benign or pathogenic, but in some cases they are beneficial for the host. The rhizosphere provides an especially rich palette for colonization by beneficial (associative and symbiotic) microorganisms, which raises the question as to how roots can distinguish such ‘friends’ from possible ‘foes’ (i.e., pathogens). Plants possess an innate immune system that can recognize pathogens, through an arsenal of protein receptors, including receptor-like kinases (RLKs) and receptor-like proteins (RLPs) located at the plasma membrane. In addition, the plant host has intracellular receptors (so called NBS-LRR proteins or R proteins) that directly or indirectly recognize molecules released by microbes into the plant cell. A successful cooperation between legume plants and rhizobia leads to beneficial symbiotic interaction. The key rhizobial, symbiotic signaling molecules [lipo-chitooligosaccharide Nod factors (NF)] are perceived by the host legume plant using lysin motif-domain containing RLKs. Perception of the symbiotic NFs trigger signaling cascades leading to bacterial infection and accommodation of the symbiont in a newly formed root organ, the nodule, resulting in a nitrogen-fixing root nodule symbiosis. The net result of this symbiosis is the intracellular colonization of the plant with thousands of bacteria; a process that seems to occur in spite of the immune ability of plants to prevent pathogen infection. In this review, we discuss the potential of the invading rhizobial symbiont to actively avoid this innate immune response, as well as specific examples of where the plant immune response may modulate rhizobial infection and host range.

Via Francis Martin
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Different ROS-Scavenging Properties of Flavonoids Determine Their Abilities to Extend Shelf Life of Tomato

Different ROS-Scavenging Properties of Flavonoids Determine Their Abilities to Extend Shelf Life of Tomato | Emerging Research in Plant Cell Biology | Scoop.it

The shelf-life of tomato (Solanum lycopersicum) fruit is determined by the processes of over-ripening and susceptibility to pathogens. Post-harvest shelf life is one of the most important traits for commercially grown tomatoes. We compared the shelf life of tomato fruit that accumulate different flavonoids and found that delayed over-ripening is associated with increased total antioxidant capacity caused by the accumulation of flavonoids in the fruit. However, reduced susceptibility to Botrytis cinerea, a major post-harvest fungal pathogen of tomato, is conferred by specific flavonoids only. We demonstrate an association between flavonoid structure, selective scavenging ability for different free radicals and reduced susceptibility to B. cinerea. Our study provides mechanistic insight into how flavonoids influence shelf life of tomato, information which could be used to improve the shelf life of tomato, and potentially of other soft fruit.

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Competitive binding of antagonistic peptides fine-tunes stomatal patterning

Competitive binding of antagonistic peptides fine-tunes stomatal patterning | Emerging Research in Plant Cell Biology | Scoop.it

During development, cells interpret complex and often conflicting signals to make optimal decisions. Plant stomata, the cellular interface between a plant and the atmosphere, develop according to positional cues, which include a family of secreted peptides called epidermal patterning factors (EPFs). How these signalling peptides orchestrate pattern formation at a molecular level remains unclear. Here we report in Arabidopsis that Stomagen (also called EPF-LIKE9) peptide, which promotes stomatal development, requires ERECTA (ER)-family receptor kinases and interferes with the inhibition of stomatal development by the EPIDERMAL PATTERNING FACTOR 2 (EPF2)–ER module. Both EPF2 and Stomagen directly bind to ER and its co-receptor TOO MANY MOUTHS. Stomagen peptide competitively replaced EPF2 binding to ER. Furthermore, application of EPF2, but not Stomagen, elicited rapid phosphorylation of downstream signalling components in vivo. Our findings demonstrate how a plant receptor agonist and antagonist define inhibitory and inductive cues to fine-tune tissue patterning on the plant epidermis.

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Overexpression of the Arabidopsis thaliana signalling peptide TAXIMIN1 affects lateral organ development

Lateral organ boundary formation is highly regulated by transcription factors and hormones such as auxins and brassinosteroids. However, in contrast to many other developmental processes in plants, no role for signalling peptides in the regulation of this process has been reported yet. The first characterization of the secreted cysteine-rich TAXIMIN (TAX) signalling peptides in Arabidopsis is presented here. TAX1 overexpression resulted in minor alterations in the primary shoot and root metabolome, abnormal fruit morphology, and fusion of the base of cauline leaves to stems forming a decurrent leaf attachment. The phenotypes at the paraclade junction match TAX1 promoter activity in this region and are similar to loss of LATERAL ORGAN FUSION (LOF) transcription factor function. Nevertheless, TAX1 expression was unchanged in lof1lof2paraclade junctions and, conversely, LOF gene expression was unchanged in TAX1 overexpressing plants, suggesting TAX1 may act independently. This study identifies TAX1 as the first plant signalling peptide influencing lateral organ separation and implicates the existence of a peptide signal cascade regulating this process in Arabidopsis.

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The Arabidopsis Transcription Factor NAC016 Promotes Drought Stress Responses by Repressing AREB1 Transcription through a Trifurcate Feed-Forward Regulatory Loop Involving NAP

The Arabidopsis Transcription Factor NAC016 Promotes Drought Stress Responses by Repressing AREB1 Transcription through a Trifurcate Feed-Forward Regulatory Loop Involving NAP | Emerging Research in Plant Cell Biology | Scoop.it

Drought and other abiotic stresses negatively affect plant growth and development and thus reduce productivity. The plant-specific NAM/ATAF1/2/CUC2 (NAC) transcription factors have important roles in abiotic stress-responsive signaling. Here, we show that Arabidopsis thaliana NAC016 is involved in drought stress responses; nac016 mutants have high drought tolerance, and NAC016-overexpressing (NAC016-OX) plants have low drought tolerance. Using genome-wide gene expression microarray analysis and MEME motif searches, we identified the NAC016-specific binding motif (NAC16BM), GATTGGAT[AT]CA, in the promoters of genes downregulated in nac016-1 mutants. The NAC16BM sequence does not contain the core NAC binding motif CACG (or its reverse complement CGTG). NAC016 directly binds to the NAC16BM in the promoter of ABSCISIC ACID-RESPONSIVE ELEMENT BINDING PROTEIN1 (AREB1), which encodes a central transcription factor in the stress-responsive abscisic acid signaling pathway and represses AREB1 transcription. We found that knockout mutants of the NAC016 target gene NAC-LIKE, ACTIVATED BY AP3/PI (NAP) also exhibited strong drought tolerance; moreover, NAP binds to the AREB1 promoter and suppresses AREB1transcription. Taking these results together, we propose that a trifurcate feed-forward pathway involving NAC016, NAP, and AREB1 functions in the drought stress response, in addition to affecting leaf senescence in Arabidopsis.

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Molecular & General Genetics: Genetic and structural characterization of the avirulence gene avrBs3 from Xanthomonas campestris pv. vesicatoria (1989)

Molecular & General Genetics: Genetic and structural characterization of the avirulence gene avrBs3 from Xanthomonas campestris pv. vesicatoria (1989) | Emerging Research in Plant Cell Biology | Scoop.it

The avirulence gene avrBs3 from Xanthomonas campestris pv. vesicatoria was cloned and found to be localized on a self-transmissable plasmid. Genetic analysis of an avrBs3 insertion mutation revealed that avrBs3 constitutes a single locus, specifying the resistant phenotype on pepper plants. Southern blot experiments showed that no DNA sequences homologous to avrBs3 were present in other races of X. c. pv. vesicatoria, which are unable to induce a hypersensitive reaction on ECW-30R. However, the DNA of several different pathovars of X. campestris hybridized to the avrBs3 probe. A deletion analysis defined a region of 3.6–3.7 kb essential for avrBs3 activity. The nucleotide sequence of this region was determined. A 3561 nucleotide open reading frame (ORF1), encoding a 125000 dalton protein, was found in the 3.7 kb region that was sufficient for avrBs3activity. A second long ORF (2351 nucleotides) was identified on the other strand. A remarkable feature of both ORFs is the presence of 17 direct repeats of 102 bp which share 91%–100% homology with each other.


Via Kamoun Lab @ TSL
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Involvement of Arabidopsis Hexokinase1 in Cell Death Mediated by Myo-Inositol Accumulation

Involvement of Arabidopsis Hexokinase1 in Cell Death Mediated by Myo-Inositol Accumulation | Emerging Research in Plant Cell Biology | Scoop.it

Programmed cell death (PCD) is essential for several aspects of plant life, including development and stress responses. We recently identified the mips1 mutant ofArabidopsis thaliana, which is deficient for the enzyme catalyzing the limiting step of myo-inositol (MI) synthesis. One of the most striking features of mips1 is the light-dependent formation of lesions on leaves due to salicylic acid (SA)-dependent PCD. Here, we identified a suppressor of PCD by screening for mutations that abolish the mips1 cell death phenotype. Our screen identified thehxk1 mutant, mutated in the gene encoding the hexokinase1 (HXK1) enzyme that catalyzes sugar phosphorylation and acts as a genuine glucose sensor. We show that HXK1 is required for lesion formation in mips1 due to alterations in MIcontent, via SA-dependant signaling. Using two catalytically inactive HXK1 mutants, we also show that hexokinase catalytic activity is necessary for the establishment of lesions in mips1. Gas chromatography-mass spectrometry analyses revealed a restoration of the MI content in mips1 hxk1 that it is due to the activity of the MIPS2 isoform, while MIPS3 is not involved. Our work defines a pathway of HXK1-mediated cell death in plants and demonstrates that two MIPSenzymes act cooperatively under a particular metabolic status, highlighting a novel checkpoint of MI homeostasis in plants.

Jennifer Mach's insight:

Hot topic alert! Myo-inositol is trending in my editing queue....

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Chitin-mediated plant–fungal interactions: catching, hiding and handshaking

Chitin-mediated plant–fungal interactions: catching, hiding and handshaking | Emerging Research in Plant Cell Biology | Scoop.it

Highlights•

Plants recognize infecting fungi through the perception of released chitin fragments by LysM receptor complexes.

Pathogenic fungi secrete effectors and change their cell walls to escape from the chitin-mediated immune system.

Chitin-related molecules also serve as symbiotic signals in rhizobium/AM symbiosis.

Dual function of OsCERK1 in both chitin-mediated immunity and AM symbiosis sheds a new light on the evolutionary relationships between these systems.

Plants can detect infecting fungi through the perception of chitin oligosaccharides by lysin motif receptors such as CEBiP and CERK1. A major function of CERK1 seems to be as a signaling molecule in the receptor complex formed with ligand-binding molecules and to activate downstream defense signaling. Fungal pathogens, however, have developed counter strategies to escape from the chitin-mediated detection by using effectors and/or changing their cell walls. Common structural features between chitin and Nod-/Myc-factors and corresponding receptors have suggested the close relationships between the chitin-mediated immunity and rhizobial/arbuscular mycorrhizal symbiosis. The recent discovery of the dual function of OsCERK1 in both plant immunity and mycorrhizal symbiosis sheds new light on the evolutionary relationships between defense and symbiotic systems in plants.

Current Opinion in Plant Biology 2015, 26:xx–


Via Christophe Jacquet
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Small RNAs—the secret agents in the plant–pathogen interactions

Small RNAs—the secret agents in the plant–pathogen interactions | Emerging Research in Plant Cell Biology | Scoop.it

Highlights•

Small RNAs regulate plant immune responses and pathogen virulence.

Small RNAs can move between interacting organisms and induce cross-kingdom RNAi.

Advanced plant pathogens use cross-kingdom RNAi to suppress host immunity genes.

Host induced gene silencing provides a mechanism whereby crops produce small RNAs to silence pathogen genes

Eukaryotic regulatory small RNAs (sRNAs) that induce RNA interference (RNAi) are involved in a plethora of biological processes, including host immunity and pathogen virulence. In plants, diverse classes of sRNAs contribute to the regulation of host innate immunity. These immune-regulatory sRNAs operate through distinct RNAi pathways that trigger transcriptional or post-transcriptional gene silencing. Similarly, many pathogen-derived sRNAs also regulate pathogen virulence. Remarkably, the influence of regulatory sRNAs is not limited to the individual organism in which they are generated. It can sometimes extend to interacting species from even different kingdoms. There they trigger gene silencing in the interacting organism, a phenomenon called cross-kingdom RNAi. This is exhibited in advanced pathogens and parasites that produce sRNAs to suppress host immunity. Conversely, in host-induced gene silencing (HIGS), diverse plants are engineered to trigger RNAi against pathogens and pests to confer host resistance. Cross-kingdom RNAi opens up a vastly unexplored area of research on mobile sRNAs in the battlefield between hosts and pathogens.


Via Christophe Jacquet
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Chloroplast Stromules Function during Innate Immunity: Developmental Cell

Chloroplast Stromules Function during Innate Immunity: Developmental Cell | Emerging Research in Plant Cell Biology | Scoop.it
•Chloroplast stromules are induced during plant immune responses•Pro-PCD signals such as SA and H2O2 induce stromules•Stromules form dynamic connections with nucleus during immune responses•Constitutively induced stromules enhance PCD during plant immune responses

 

Summary

Inter-organellar communication is vital for successful innate immune responses that confer defense against pathogens. However, little is known about how chloroplasts, which are a major production site of pro-defense molecules, communicate and coordinate with other organelles during defense. Here we show that chloroplasts send out dynamic tubular extensions called stromules during innate immunity or exogenous application of the pro-defense signals, hydrogen peroxide (H2O2) and salicylic acid. Interestingly, numerous stromules surround nuclei during defense response, and these connections correlate with an accumulation of chloroplast-localized NRIP1 defense protein and H2O2 in the nucleus. Furthermore, silencing and knockout ofchloroplast unusual positioning 1 (CHUP1) that encodes a chloroplast outer envelope protein constitutively induces stromules in the absence of pathogen infection and enhances programmed cell death. These results support a model in which stromules aid in the amplification and/or transport of pro-defense signals into the nucleus and other subcellular compartments during immunity.

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Genomics as the key to unlocking the polyploid potential of wheat

Genomics as the key to unlocking the polyploid potential of wheat | Emerging Research in Plant Cell Biology | Scoop.it

Polyploidy has played a central role in plant genome evolution and in the formation of new species such as tetraploid pasta wheat and hexaploid bread wheat. Until recently, the high sequence conservation between homoeologous genes, together with the large genome size of polyploid wheat, had hindered genomic analyses in this important crop species. In the past 5 yr, however, the advent of next-generation sequencing has radically changed the wheat genomics landscape. Here, we review a series of advances in genomic resources and tools for functional genomics that are shifting the paradigm of what is possible in wheat molecular genetics and breeding. We discuss how understanding the relationship between homoeologues can inform approaches to modulate the response of quantitative traits in polyploid wheat; we also argue that functional redundancy has ‘locked up’ a wide range of phenotypic variation in wheat. We explore how genomics provides key tools to inform targeted manipulation of multiple homoeologues, thereby allowing researchers and plant breeders to unlock the full polyploid potential of wheat.

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Genome Sequencing of Arabidopsis abp1-5 Reveals Second-Site Mutations That May Affect Phenotypes

Genome Sequencing of Arabidopsis abp1-5 Reveals Second-Site Mutations That May Affect Phenotypes | Emerging Research in Plant Cell Biology | Scoop.it

Another chink in the ABP armor - ABP1 was identified back in the 1970s as an Auxin Binding Protein. Evidence for its functional role came from knock-down studies using antisense RNA, intereferring with its function by the addition of monoclonal antibodies, and finally the identification of Arabidopsis mutants, which were difficult to study as they conferred an embryo-lethal phenotype. Subsequently, a weaker allele was identified, abp1-5, with a phenotype consistent with a role for ABP in auxin signaling.

Earlier this year, Gao et al got our attention by generating mutations in the ABP gene using genome-editing CRISPR technology; the advantage of this approach is it doesn't subject the genome to other off-site mutations. Gao et al stated, "Auxin binding protein 1 (ABP1) is not required for either auxin signaling or Arabidopsis development", which raised questions about the origin of the phenotypes described previously (http://www.pnas.org/content/112/7/2275.abstract).

Now a new study suggests that the phenotype of abp1-5 could come at least in part from those other, messy mutations. By sequencing the whole genome of abp1-5 (an approach that was not readily available until recently), Enders et al found "Genome Sequencing of Arabidopsis abp1-5 Reveals Second-Site Mutations That May Affect Phenotypes" (http://www.plantcell.org/content/early/2015/06/23/tpc.15.00214.abstract).

There are still unanswered questions, but this new study is an important contribution to the question of ABP1 function, and a good paper with which to show that the path to knowledge is not always obstacle free.


Via Mary Williams
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New Phytologist - Volume 207, Issue 2 - Evolutionary plant radiations - Wiley Online Library

New Phytologist - Volume 207, Issue 2 - Evolutionary plant radiations - Wiley Online Library | Emerging Research in Plant Cell Biology | Scoop.it
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Multilayered Organization of Jasmonate Signalling in the Regulation of Root Growth

Multilayered Organization of Jasmonate Signalling in the Regulation of Root Growth | Emerging Research in Plant Cell Biology | Scoop.it
Author Summary The study of plant development is generally carried out in the absence of physical injury. However, damage to plant organs through biotic and abiotic insult is common in nature. Under these conditions the jasmonate pathway that has a low activity in unstressed vegetative tissues imposes its activity on cell division and elongation. Such jasmonate-dependent growth restriction can strongly impact plant productivity. Taking roots as a model, we show that it is possible to manipulate regulatory layers in jasmonate signalling such that cell division and cell elongation can be constrained differently. This approach may lead to future strategies to alter organ growth. Moreover, during this study we identified a novel mutant in a key regulator of the jasmonate pathway. This mutant generated a positive regulator of jasmonate signalling that was so active that we were able to show that hormone synthesis can be completely uncoupled from hormone responses, suggesting ways to modify traits of potential agronomic importance.
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Moss-made pharmaceuticals: from bench to bedside

Moss-made pharmaceuticals: from bench to bedside | Emerging Research in Plant Cell Biology | Scoop.it

Over the past two decades, the moss Physcomitrella patens has been developed from scratch to a model species in basic research and in biotechnology. A fully sequenced genome, outstanding possibilities for precise genome-engineering via homologous recombination (knockout moss), a certified GMP production in moss bioreactors, successful upscaling to 500 L wave reactors, excellent homogeneity of protein glycosylation, remarkable batch-to-batch stability and a safe cryopreservation for master cell banking are some of the key features of the moss system. Several human proteins are being produced in this system as potential biopharmaceuticals. Among the products are tumour-directed monoclonal antibodies with enhanced antibody-dependent cytotoxicity (ADCC), vascular endothelial growth factor (VEGF), complement factor H (FH), keratinocyte growth factor (FGF7/KGF), epidermal growth factor (EGF), hepatocyte growth factor (HGF), asialo-erythropoietin (asialo-EPO, AEPO), alpha-galactosidase (aGal) and beta-glucocerebrosidase (GBA). Further, an Env-derived multi-epitope HIV protein as a candidate vaccine was produced, and first steps for a metabolic engineering of P. patens have been made. Some of the recombinant biopharmaceuticals from moss bioreactors are not only similar to those produced in mammalian systems such as CHO cells, but are of superior quality (biobetters). The first moss-made pharmaceutical, aGal to treat Morbus Fabry, is in clinical trials.

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Domesticated versus Wild Rice? Bring It Awn!

Domesticated versus Wild Rice? Bring It Awn! | Emerging Research in Plant Cell Biology | Scoop.it

In Brief mini-review on awn formation in rice.

Jennifer Mach's insight:

Featured article here:  http://www.plantcell.org/content/early/2015/06/16/tpc.15.00260.abstract

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Getting the ‘MOST’ out of crop improvement: Trends in Plant Science

Getting the ‘MOST’ out of crop improvement: Trends in Plant Science | Emerging Research in Plant Cell Biology | Scoop.it
•We propose ‘molecular strengthening’ (MOST) to improve crop performance.•MOST treatments help to maximize trait expression for any given genotype and counteract environmental conditions.•Detailed molecular genetic information is essential for development of MOST treatments.•MOST treatments can be combined with current breeding methods like marker aided selection, transgenics, and genomic selection.

 

Unraveling the function of genes affecting agronomic traits is accelerating due to progress in DNA sequencing and other high-throughput genomic approaches. Characterized genes can be exploited by plant breeders by using either marker-aided selection (MAS) or transgenic procedures. Here, we propose a third ‘outlet’, ‘molecular strengthening’ (MOST), as alternative option for exploiting detailed molecular understanding of trait expression, which is comparable to the pharmaceutical treatment of human diseases. MOST treatments can be used to enhance yield stability. Alternatively, they can be used to control traits temporally, such as flowering time to facilitate crosses for plant breeders. We also discuss the essence for developing MOST treatments, their prospects, and limitations.

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Rescooped by Jennifer Mach from Plant roots and rhizosphere
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Differential Roles of PIN1 and PIN2 in Root Meristem Maintenance Under Low-B Conditions in Arabidopsis thaliana

Differential Roles of PIN1 and PIN2 in Root Meristem Maintenance Under Low-B Conditions in Arabidopsis thaliana | Emerging Research in Plant Cell Biology | Scoop.it
Boron (B) is an essential element for plants; its deficiency causes rapid cessation of root elongation. In addition, B influences auxin accumulation in plants. To assess the importance of auxin transport in B-dependent root elongation, Arabidopsis thaliana pin1–pin4 mutants were grown under low-B conditions. Among them, only the pin2/eir1-1 mutant showed a significantly shorter root under low-B conditions than under control conditions. Moreover, the root meristem size of pin2/eir1-1 was reduced under low-B conditions. Among the PIN-FORMED (PIN) family, PIN1 and PIN2 are important for root meristem growth/maintenance under normal conditions. To investigate the differential response of pin1 and pin2 mutants under low-B conditions, the effect of low-B on PIN1–green fluorescent protein (GFP) and PIN2–GFP accumulation and localization was examined. Low-B did not affect PIN2–GFP, while it reduced the accumulation of PIN1–GFP. Moreover, no signal from DII-VENUS, an auxin sensor, was detected under the low-B condition in the stele of wild-type root meristems. Taken together, these results indicate that under low-B conditions PIN1 is down-regulated and PIN2 plays an important role in root meristem maintenance.

Via Christophe Jacquet
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Rescooped by Jennifer Mach from Plant immunity and legume symbiosis
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14-3-3 Proteins in Plant-Pathogen Interactions

14-3-3 Proteins in Plant-Pathogen Interactions | Emerging Research in Plant Cell Biology | Scoop.it

14-3-3 proteins define a eukaryotic-specific protein family with a general role in signal transduction. Primarily, 14-3-3 proteins act as phosphosensors, binding phosphorylated client proteins and modulating their functions. Since phosphorylation regulates a plethora of different physiological responses in plants, 14-3-3 proteins play roles in multiple signaling pathways, including those controlling metabolism, hormone signaling, cell division, and responses to abiotic and biotic stimuli. Increasing evidence supports a prominent role of 14-3-3 proteins in regulating plant immunity against pathogens at various levels. In this review, potential links between 14-3-3 function and the regulation of plant-pathogen interactions are discussed, with a special focus on the regulation of 14-3-3 proteins in response to pathogen perception, interactions between 14-3-3 proteins and defense-related proteins, and 14-3-3 proteins as targets of pathogen effectors.


Via Christophe Jacquet
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