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PLOS ONE: Effect of Stacked Insecticidal Cry Proteins from Maize Pollen on Nurse Bees (Apis mellifera carnica) and Their Gut Bacteria

PLOS ONE: Effect of Stacked Insecticidal Cry Proteins from Maize Pollen on Nurse Bees (Apis mellifera carnica) and Their Gut Bacteria | plant cell genetics | Scoop.it

Honey bee pollination is a key ecosystem service to nature and agriculture. However, biosafety research on genetically modified crops rarely considers effects on nurse bees from intact colonies, even though they receive and primarily process the largest amount of pollen. The objective of this study was to analyze the response of nurse bees and their gut bacteria to pollen from Bt maize expressing three different insecticidal Cry proteins (Cry1A.105, Cry2Ab2, and Cry3Bb1). Naturally Cry proteins are produced by bacteria (Bacillus thuringiensis). Colonies of Apis mellifera carnica were kept during anthesis in flight cages on field plots with the Bt maize, two different conventionally bred maize varieties, and without cages, 1-km outside of the experimental maize field to allow ad libitum foraging to mixed pollen sources. During their 10-days life span, the consumption of Bt maize pollen had no effect on their survival rate, body weight and rates of pollen digestion compared to the conventional maize varieties. As indicated by ELISA-quantification of Cry1A.105 and Cry3Bb1, more than 98% of the recombinant proteins were degraded. Bacterial population sizes in the gut were not affected by the genetic modification. Bt-maize, conventional varieties and mixed pollen sources selected for significantly different bacterial communities which were, however, composed of the same dominant members, including Proteobacteria in the midgut and Lactobacillus sp. and Bifidobacterium sp. in the hindgut. Surprisingly, Cry proteins from natural sources, most likely B. thuringiensis, were detected in bees with no exposure to Bt maize. The natural occurrence of Cry proteins and the lack of detectable effects on nurse bees and their gut bacteria give no indication for harmful effects of this Bt maize on nurse honey bees.

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Jack's curator insight, April 9, 2013 3:58 PM

It struck me as surprising that the bulk of bacteria's responsible for digesting the bee's pollen was still in tact. But i would say it is important to first study the effects of each bacteria in the digestive tract of the bees to truly evaluate if the differences in the hindgut can be rendered severe or not to the nurse bees health.

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Vip3Aa and Cry1Ab proteins in maize reduce Fusarium ear rot and fumonisins by deterring kernel injury from multiple Lepidopteran pests - Bowers &al (2013) - World Mycotox J

Vip3Aa and Cry1Ab proteins in maize reduce Fusarium ear rot and fumonisins by deterring kernel injury from multiple Lepidopteran pests - Bowers &al (2013) - World Mycotox J | plant cell genetics | Scoop.it

Field trials were conducted in 2008, 2009 and 2011 to assess fumonisin contamination in transgenic (Bt) and non-Bt maize hybrids infested with European corn borer, corn earworm, and Western bean cutworm. Comparisons were made among maize hybrids expressing two transgenic insect resistance proteins (Cry1Ab × Vip3Aa), a single resistance protein (Cry1Ab), or no insect resistance. The field design was a randomised complete block design with four replicates of each hybrid × insect combination. 

Kernel injury, Fusarium ear rot, and fumonisins (FB1+FB2+FB3) in maize grain were measured. These measurements differed significantly among years of the study. In all years, significant positive correlations were present between insect injury and Fusarium ear rot, insect injury and grain fumonisin levels, and Fusarium ear rot and grain fumonisin levels. 

Under all insect infestation treatments, Cry1Ab × Vip3Aa hybrids were the most resistant of the hybrids with regard to any of the grain quality measurements. Averaged over all insect infestations and years, insect injury, Fusarium ear rot, and grain fumonisin levels were all low in Cry1Ab × Vip3Aa (0.1% and 2.2% of total kernels, and 0.56 mg/kg, respectively). The highest average levels of insect injury, Fusarium ear rot, and grain fumonisin contamination (3.3% and 7.2% of total kernels, and 5.47 mg/kg, respectively) were found in the non-Bt hybrids. 

The presence of transgenic insect protection (Cry1Ab × Vip3Aa or Cry1Ab) resulted in significant reductions in all grain quality measurements as compared with the non-Bt hybrids. Only grain obtained from Cry1Ab × Vip3Aa hybrids consistently had acceptable fumonisin content according to both US guidance levels and EU regulatory limits. These results indicate that Cry1Ab × Vip3Aa maize hybrids are more likely to yield high quality, low-fumonisin grain compared to hybrids expressing only Cry1Ab or lacking insect resistance.


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Auxin promotes susceptibility to Pseudomonas syringae via a mechanism independent of suppression of salicylic acid-mediated defenses

Auxin promotes susceptibility to Pseudomonas syringae via a mechanism independent of suppression of salicylic acid-mediated defenses | plant cell genetics | Scoop.it

Auxin is a key plant growth regulator that also impacts plant–pathogen interactions. Several lines of evidence suggest that the bacterial plant pathogen Pseudomonas syringae manipulates auxin physiology in Arabidopsis thaliana to promote pathogenesis. Pseudomonas syringae strategies to alter host auxin biology include synthesis of the auxin indole-3-acetic acid (IAA) and production of virulence factors that alter auxin responses in host cells. The application of exogenous auxin enhances disease caused by P. syringae strain DC3000. This is hypothesized to result from antagonism between auxin and salicylic acid (SA), a major regulator of plant defenses, but this hypothesis has not been tested in the context of infected plants. We further investigated the role of auxin during pathogenesis by examining the interaction of auxin and SA in the context of infection in plants with elevated endogenous levels of auxin. We demonstrated that elevated IAA biosynthesis in transgenic plants overexpressing the YUCCA 1 (YUC1) auxin biosynthesis gene led to enhanced susceptibility to DC3000. Elevated IAA levels did not interfere significantly with host defenses, as effector-triggered immunity was active in YUC1-overexpressing plants, and we observed only minor effects on SA levels and SA-mediated responses. Furthermore, a plant line carrying both the YUC1-overexpression transgene and the salicylic acid induction deficient 2 (sid2) mutation, which impairs SA synthesis, exhibited additive effects of enhanced susceptibility from both elevated auxin levels and impaired SA-mediated defenses. Thus, in IAA overproducing plants, the promotion of pathogen growth occurs independently of suppression of SA-mediated defenses.

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Gene family evolution in green plants with emphasis on the origination and evolution of Arabidopsis thaliana genes

Gene family evolution in green plants with emphasis on the origination and evolution of Arabidopsis thaliana genes | plant cell genetics | Scoop.it

Gene family size variation is an important mechanism that shapes the natural variation for adaptation in various species. Despite its importance, the pattern of gene family size variation in green plants is still not well understood. In particular, the evolutionary pattern of genes and gene families remains unknown in the model plant Arabidopsis thaliana in the context of green plants. In this study, eight representative genomes of green plants are sampled to study gene family evolution and characterize the origination of A. thaliana genes, respectively. Four important insights gained are that: (i) the rate of gene gains and losses is about 0.001359 per gene every million years, similar to the rate in yeast, Drosophila, and mammals; (ii) some gene families evolved rapidly with extreme expansions or contractions, and 2745 gene families present in all the eight species represent the ‘core’ proteome of green plants; (iii) 70% of A. thaliana genes could be traced back to 450 million years ago; and (iv) intriguingly, A. thaliana genes with early origination are under stronger purifying selection and more conserved. In summary, the present study provides genome-wide insights into evolutionary history and mechanisms of genes and gene families in green plants and especially in A. thaliana.

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Potential shortfall of pyramided transgenic cotton for insect resistance management

Potential shortfall of pyramided transgenic cotton for insect resistance management | plant cell genetics | Scoop.it

To delay evolution of pest resistance to transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt), the “pyramid” strategy uses plants that produce two or more toxins that kill the same pest. In the United States, this strategy has been adopted widely, with two-toxin Bt cotton replacing one-toxin Bt cotton. Although two-toxin plants are likely to be more durable than one-toxin plants, the extent of this advantage depends on several conditions. One key assumption favoring success of two-toxin plants is that they kill insects selected for resistance to one toxin, which is called “redundant killing.” Here we tested this assumption for a major pest, Helicoverpa zea, on transgenic cotton producing Bt toxins Cry1Ac and Cry2Ab. Selection with Cry1Ac increased survival on two-toxin cotton, which contradicts the assumption. The concentration of Cry1Ac and Cry2Ab declined during the growing season, which would tend to exacerbate this problem. Furthermore, analysis of results from 21 selection experiments with eight species of lepidopteran pests indicates that some cross-resistance typically occurs between Cry1A and Cry2A toxins. Incorporation of empirical data into simulation models shows that the observed deviations from ideal conditions could greatly reduce the benefits of the pyramid strategy for pests like H. zea, which have inherently low susceptibility to Bt toxins and have been exposed extensively to one of the toxins in the pyramid before two-toxin plants are adopted. For such pests, the pyramid strategy could be improved by incorporating empirical data on deviations from ideal assumptions about redundant killing and cross-resistance.

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OsLG1 regulates a closed panicle trait in domesticated rice- Nature Genetics

OsLG1 regulates a closed panicle trait in domesticated rice- Nature Genetics | plant cell genetics | Scoop.it

Reduction in seed shattering was an important phenotypic change during cereal domestication1, 2. Here we show that a simple morphological change in rice panicle shape, controlled by the SPR3 locus, has a large impact on seed-shedding and pollinating behaviors. In the wild genetic background of rice, we found that plants with a cultivated-like type of closed panicle had significantly reduced seed shedding through seed retention. In addition, the long awns in closed panicles disturbed the free exposure of anthers and stigmas on the flowering spikelets, resulting in a significant reduction of the outcrossing rate. We localized the SPR3 locus to a 9.3-kb genomic region, and our complementation tests suggest that this region regulates the liguleless gene (OsLG1). Sequencing analysis identified reduced nucleotide diversity and a selective sweep at the SPR3 locus in cultivated rice. Our results suggest that a closed panicle was a selected trait during rice domestication.


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Homologous recombination-mediated gene targeting in the liverwort Marchantia polymorpha L.

Homologous recombination-mediated gene targeting in the liverwort Marchantia polymorpha L. | plant cell genetics | Scoop.it

The liverwort Marchantia polymorpha is an emerging model organism on account of its ideal characteristics for molecular genetics in addition to occupying a crucial position in the evolution of land plants. Here we describe a method for gene targeting by applying a positive/negative selection system for reduction of non-homologous random integration to an efficient Agrobacterium-mediated transformation system using M. polymorpha sporelings. The targeting efficiency was evaluated by knocking out the NOP1 gene, which impaired air-chamber formation. Homologous recombination was observed in about 2% of the thalli that passed the positive/negative selection. With the advantage of utilizing the haploid gametophytic generation, this strategy should facilitate further molecular genetic analysis of M. polymorpha, in which many of the mechanisms found in land plants are conserved, yet in a less complex form.

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Interesting paper but why  using Agrobacterium transformation in place of direct naked DNA (not as successful as Physcomitrella patens)

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Effect of Stacked Insecticidal Cry Proteins from Maize Pollen on Nurse Bees (Apis mellifera carnica) and Their Gut Bacteria - Hendriksma &al (2013) - PLoS ONE

Effect of Stacked Insecticidal Cry Proteins from Maize Pollen on Nurse Bees (Apis mellifera carnica) and Their Gut Bacteria - Hendriksma &al (2013) - PLoS ONE | plant cell genetics | Scoop.it

Honey bee pollination is a key ecosystem service to nature and agriculture. However, biosafety research on genetically modified crops rarely considers effects on nurse bees from intact colonies, even though they receive and primarily process the largest amount of pollen. The objective of this study was to analyze the response of nurse bees and their gut bacteria to pollen from Bt maize expressing three different insecticidal Cry proteins (Cry1A.105, Cry2Ab2, and Cry3Bb1). Naturally Cry proteins are produced by bacteria (Bacillus thuringiensis).

 

Colonies of Apis mellifera carnica were kept during anthesis in flight cages on field plots with the Bt maize, two different conventionally bred maize varieties, and without cages, 1-km outside of the experimental maize field to allow ad libitum foraging to mixed pollen sources. During their 10-days life span, the consumption of Bt maize pollen had no effect on their survival rate, body weight and rates of pollen digestion compared to the conventional maize varieties.

 

As indicated by ELISA-quantification of Cry1A.105 and Cry3Bb1, more than 98% of the recombinant proteins were degraded. Bacterial population sizes in the gut were not affected by the genetic modification. Bt-maize, conventional varieties and mixed pollen sources selected for significantly different bacterial communities which were, however, composed of the same dominant members, including Proteobacteria in the midgut and Lactobacillus sp. andBifidobacterium sp. in the hindgut.

 

Surprisingly, Cry proteins from natural sources, most likelyB. thuringiensis, were detected in bees with no exposure to Bt maize. The natural occurrence of Cry proteins and the lack of detectable effects on nurse bees and their gut bacteria give no indication for harmful effects of this Bt maize on nurse honey bees. 


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Aluminum tolerance in maize is associated with higher MATE1 gene copy number

Aluminum tolerance in maize is associated with higher MATE1 gene copy number | plant cell genetics | Scoop.it

Genome structure variation, including copy number variation and presence/absence variation, comprises a large extent of maize genetic diversity; however, its effect on phenotypes remains largely unexplored. Here, we describe how copy number variation underlies a rare allele that contributes to maize aluminum (Al) tolerance. Al toxicity is the primary limitation for crop production on acid soils, which make up 50% of the world’s potentially arable lands. In a recombinant inbred line mapping population, copy number variation of the Al tolerance gene multidrug and toxic compound extrusion 1 (MATE1) is the basis for the quantitative trait locus of largest effect on phenotypic variation. This expansion in MATE1 copy number is associated with higher MATE1 expression, which in turn results in superior Al tolerance. The three MATE1 copies are identical and are part of a tandem triplication. Only three maize inbred lines carrying the three-copy allele were identified from maize and teosinte diversity panels, indicating that copy number variation for MATE1 is a rare, and quite likely recent, event. These maize lines with higher MATE1 copy number are also Al-tolerant, have high MATE1 expression, and originate from regions of highly acidic soils. Our findings show a role for copy number variation in the adaptation of maize to acidic soils in the tropics and suggest that genome structural changes may be a rapid evolutionary response to new environments.

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A Major Facilitator Superfamily Transporter Plays a Dual Role in Polar Auxin Transport and Drought Stress Tolerance in Arabidopsis

A Major Facilitator Superfamily Transporter Plays a Dual Role in Polar Auxin Transport and Drought Stress Tolerance in Arabidopsis | plant cell genetics | Scoop.it

Many key aspects of plant development are regulated by the polarized transport of the phytohormone auxin. Cellular auxin efflux, the rate-limiting step in this process, has been shown to rely on the coordinated action of PIN-formed (PIN) and B-type ATP binding cassette (ABCB) carriers. Here, we report that polar auxin transport in the Arabidopsis thaliana root also requires the action of a Major Facilitator Superfamily (MFS) transporter, Zinc-Induced Facilitator-Like 1 (ZIFL1). Sequencing, promoter-reporter, and fluorescent protein fusion experiments indicate that the full-length ZIFL1.1 protein and a truncated splice isoform, ZIFL1.3, localize to the tonoplast of root cells and the plasma membrane of leaf stomatal guard cells, respectively. Using reverse genetics, we show that the ZIFL1.1 transporter regulates various root auxin-related processes, while the ZIFL1.3 isoform mediates drought tolerance by regulating stomatal closure. Auxin transport and immunolocalization assays demonstrate that ZIFL1.1 indirectly modulates cellular auxin efflux during shootward auxin transport at the root tip, likely by regulating plasma membrane PIN2 abundance. Finally, heterologous expression in yeast revealed that ZIFL1.1 and ZIFL1.3 share H+-coupled K+ transport activity. Thus, by determining the subcellular and tissue distribution of two isoforms, alternative splicing dictates a dual function for the ZIFL1 transporter. We propose that this MFS carrier regulates stomatal movements and polar auxin transport by modulating potassium and proton fluxes in Arabidopsis cells.

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Detection and Learning of Floral Electric Fields by Bumblebee

Detection and Learning of Floral Electric Fields by Bumblebee | plant cell genetics | Scoop.it

Insects use several senses to forage, detecting floral cues such as color, shape, pattern, and volatiles. We report a formerly unappreciated sensory modality in bumblebees (Bombus terrestris), detection of floral electric fields. These fields act as floral cues, which are affected by the visit of naturally charged bees. Like visual cues, floral electric fields exhibit variations in pattern and structure, which can be discriminated by bumblebees. We also show that such electric field information contributes to the complex array of floral cues that together improve a pollinator's memory of floral rewards. Because floral electric fields can change within seconds, this sensory modality may facilitate rapid and dynamic communication between flowers and their pollinators.

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IJMS | Free Full-Text | Activation of Defense Mechanisms against Pathogens in Mosses and Flowering Plants

IJMS | Free Full-Text | Activation of Defense Mechanisms against Pathogens in Mosses and Flowering Plants | plant cell genetics | Scoop.it

During evolution, plants have developed mechanisms to cope with and adapt to different types of stress, including microbial infection. Once the stress is sensed, signaling pathways are activated, leading to the induced expression of genes with different roles in defense. Mosses (Bryophytes) are non-vascular plants that diverged from flowering plants more than 450 million years ago, allowing comparative studies of the evolution of defense-related genes and defensive metabolites produced after microbial infection. The ancestral position among land plants, the sequenced genome and the feasibility of generating targeted knock-out mutants by homologous recombination has made the moss Physcomitrella patens an attractive model to perform functional studies of plant genes involved in stress responses. This paper reviews the current knowledge of inducible defense mechanisms in P. patens and compares them to those activated in flowering plants after pathogen assault, including the reinforcement of the cell wall, ROS production, programmed cell death, activation of defense genes and synthesis of secondary metabolites and defense hormones. The knowledge generated in P. patens together with comparative studies in flowering plants will help to identify key components in plant defense responses and to design novel strategies to enhance resistance to biotic stress

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KNOX2 Genes Regulate the Haploid-to-Diploid Morphological Transition in Land Plants

KNOX2 Genes Regulate the Haploid-to-Diploid Morphological Transition in Land Plants | plant cell genetics | Scoop.it

Unlike animals, land plants undergo an alternation of generations, producing multicellular bodies in both haploid (1n: gametophyte) and diploid (2n: sporophyte) generations. Plant body plans in each generation are regulated by distinct developmental programs initiated at either meiosis or fertilization, respectively. In mosses, the haploid gametophyte generation is dominant, whereas in vascular plants—including ferns, gymnosperms, and angiosperms—the diploid sporophyte generation is dominant. Deletion of the class 2 KNOTTED1-LIKE HOMEOBOX (KNOX2) transcription factors in the moss Physcomitrella patens results in the development of gametophyte bodies from diploid embryos without meiosis. Thus, KNOX2 acts to prevent the haploid-specific body plan from developing in the diploid plant body, indicating a critical role for the evolution of KNOX2 in establishing an alternation of generations in land plants

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Jack's curator insight, April 8, 2013 3:42 PM

This is fascinating, understanding how plant species form and stabilize into what they are is crucial into utilizing the potential of the Genomics of Botany to help our world in the future.

Jack's comment, April 8, 2013 3:48 PM
My thoughts - I hadn't any idea that land plants alternate between haplodid and diploid states stabilizing (as a species) in the one that is more successful in the given scenario. Given this information several questions are raised, how would different versions (haploid and diploid) of these plants fare in the mapping of their genetics, and how would mapping these same (but different) genetics round our view on the genetics of plants overall?
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Horizontal gene transfer in the innovation and adaptation of land plants

Horizontal gene transfer in the innovation and adaptation of land plants | plant cell genetics | Scoop.it

Horizontal gene transfer (HGT) has been well documented in prokaryotes and unicellular eukaryotes, but its role in plants and animals remains elusive. In a recent study, we showed that at least 57 families of nuclear genes in the moss Physcomitrella patens were acquired from prokaryotes, fungi or viruses and that HGT played a critical role in plant colonization of land. In this paper, we categorize all acquired genes based on their putative functions and biological processes, and further address the importance of HGT in plant innovation and evolution.

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Key environmental impacts of global genetically modified (GM) crop use 1996-2011 - Barfoot & Brookes (2013) - GM Crops and Food

Key environmental impacts of global genetically modified (GM) crop use 1996-2011 - Barfoot & Brookes (2013) - GM Crops and Food | plant cell genetics | Scoop.it

Given the increasing awareness and appreciation of issues such as global warming and the impact of mankind's activities such as agriculture on the global environment, this paper updates previous assessments of the environmental impact... crop biotechnology has had on global agriculture. It focuses on the environmental impacts associated with changes in pesticide use and greenhouse gas emissions arising from the use of GM crops.

 

The adoption of the technology has reduced pesticide spraying by 474 million kg (-8.9%) and, as a result, decreased the environmental impact associated with herbicide and insecticide use on these crops (as measured by the indicator the Environmental Impact Quotient (EIQ)) by18.1%. The technology has also facilitated a significant reduction in the release of greenhouse gas emissions from this cropping area, which, in 2011, was equivalent to removing 10.22 million cars from the roads.


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The manipulation of auxin in the abscission zone cells of Arabidopsis flowers reveals that IAA signaling is a prerequisite for organ shedding

A number of novel strategies were employed to examine the role of indoleacetic acid (IAA) in regulating floral organ abscission in Arabidopsis thaliana. Analysis of auxin influx facilitator expression in GUS reporter plants revealed that AUX1, LAX1 and LAX3 were specifically up-regulated at the site of floral organ shedding. Flowers from mutants where individual family members were down-regulated exhibited a reduction in the force necessary to bring about petal separation, however, the effect was not additive in double or quadruple mutants. Using the promoter of a polygalacturonase (At2g41850), active primarily in cells undergoing separation, to drive expression of the bacterial genes iaaL or iaaM we have shown that it is possible to manipulate auxin activity specifically within the floral organ abscission zones (AZ). Analysis of petal breakstrength reveals that if IAA AZ levels are reduced shedding takes place prematurely while if they are enhanced organ loss is delayed. The At2g41850 promoter was also used to trans-activate the gain-of-function AXR3-1 gene in order to disrupt auxin signaling specifically within the floral organ AZ cells. Flowers from trans-activated lines failed to shed their sepals, petals and anthers during pod expansion and maturity and these organs frequently remained attached to the plant even after silique desiccation and dehiscence had taken place. These observations support a key role for IAA in the regulation of abscission in planta and reveal, for the first time, a requirement for a functional IAA-signaling pathway in AZ cells for organ shedding to take place.


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Biswapriya Biswavas Misra's curator insight, April 2, 2013 4:15 AM
Abstract

A number of novel strategies were employed to examine the role of indoleacetic acid (IAA) in regulating floral organ abscission in Arabidopsis thaliana. Analysis of auxin influx facilitator expression in GUS reporter plants revealed that AUX1, LAX1 and LAX3 were specifically up-regulated at the site of floral organ shedding. Flowers from mutants where individual family members were down-regulated exhibited a reduction in the force necessary to bring about petal separation, however, the effect was not additive in double or quadruple mutants. Using the promoter of a polygalacturonase (At2g41850), active primarily in cells undergoing separation, to drive expression of the bacterial genes iaaL or iaaM we have shown that it is possible to manipulate auxin activity specifically within the floral organ abscission zones (AZ). Analysis of petal breakstrength reveals that if IAA AZ levels are reduced shedding takes place prematurely while if they are enhanced organ loss is delayed. The At2g41850 promoter was also used to trans-activate the gain-of-function AXR3-1 gene in order to disrupt auxin signaling specifically within the floral organ AZ cells. Flowers from trans-activated lines failed to shed their sepals, petals and anthers during pod expansion and maturity and these organs frequently remained attached to the plant even after silique desiccation and dehiscence had taken place. These observations support a key role for IAA in the regulation of abscission in planta and reveal, for the first time, a requirement for a functional IAA-signaling pathway in AZ cells for organ shedding to take place.

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Genome-wide identification and characterization of microRNA genes and their targets in flax (Linum usitatissimum) - Springer

Genome-wide identification and characterization of microRNA genes and their targets in flax (Linum usitatissimum) - Springer | plant cell genetics | Scoop.it
MicroRNAs (miRNAs) are small (20–24 nucleotide long) endogenous regulatory RNAs that play important roles in plant growth and development. They regulate gene expression at the post-transcriptional level by translational repression or target degradation and gene silencing. In this study, we identified 116 conserved miRNAs belonging to 23 families from the flax (Linum usitatissimum L.) genome using a computational approach. The precursor miRNAs varied in length; while most of the mature miRNAs were 21 nucleotide long, intergenic and showed conserved signatures of RNA polymerase II transcripts in their upstream regions. Promoter region analysis of the flax miRNA genes indicated prevalence of MYB transcription factor binding sites. Four miRNA gene clusters containing members of three phylogenetic groups were identified. Further, 142 target genes were predicted for these miRNAs and most of these represent transcriptional regulators. The miRNA encoding genes were expressed in diverse tissues as determined by digital expression analysis as well as real-time PCR. The expression of fourteen miRNAs and nine target genes was independently validated using the quantitative reverse transcription PCR (qRT-PCR). This study suggests that a large number of conserved plant miRNAs are also found in flax and these may play important roles in growth and development of flax. 
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Large-scale, spatially-explicit test of the refuge strategy for delaying insecticide resistance

Large-scale, spatially-explicit test of the refuge strategy for delaying insecticide resistance | plant cell genetics | Scoop.it

The refuge strategy is used worldwide to delay the evolution of pest resistance to insecticides that are either sprayed or produced by transgenic Bacillus thuringiensis (Bt) crops. This strategy is based on the idea that refuges of host plants where pests are not exposed to an insecticide promote survival of susceptible pests. Despite widespread adoption of this approach, large-scale tests of the refuge strategy have been problematic. Here we tested the refuge strategy with 8 y of data on refuges and resistance to the insecticide pyriproxyfen in 84 populations of the sweetpotato whitefly (Bemisia tabaci) from cotton fields in central Arizona. We found that spatial variation in resistance to pyriproxyfen within each year was not affected by refuges of melons or alfalfa near cotton fields. However, resistance was negatively associated with the area of cotton refuges and positively associated with the area of cotton treated with pyriproxyfen. A statistical model based on the first 4 y of data, incorporating the spatial distribution of cotton treated and not treated with pyriproxyfen, adequately predicted the spatial variation in resistance observed in the last 4 y of the study, confirming that cotton refuges delayed resistance and treated cotton fields accelerated resistance. By providing a systematic assessment of the effectiveness of refuges and the scale of their effects, the spatially explicit approach applied here could be useful for testing and improving the refuge strategy in other crop–pest systems.

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The Many Influences of RNA on the Genome

The Many Influences of RNA on the Genome | plant cell genetics | Scoop.it

Here's a nice pan-kingdom reivew of noncoding RNAs of all flavors!


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Bringing light in the discussion about GMOs? – A rather long reading list

[updated 15 March, 2013]  

 

These days I received an apparently easy request: “Do you have any recommendations for reading about the debate on GMOs? I think there is a lot of heat, but too little light in the discussion; I trust you can send me some…” To which I answered carelessly: “Sure, I will look into it, select a few references and post them…” 

 

I thought I’d have a quick look into my collection of bookmarks and references and post some of the links to satisfy the request. Obviously there would be too many individual studies and crop-specific or country-specific reports, but focusing only (i) on what was published over the last couple of years, (ii) on sources where all this information was already aggregated (literature reviews, meta-analyses, authoritative statements, FAQs, etc.), and (iii) on academic or publicly funded sources should produce a fairly concise list, I thought.

 

While not unmanageable, the list has become quite long. To get a rough idea of the current state of knowledge, it may be sufficient to peruse the first 1-2 (starred *) references under each heading, and to have a quick look at the abstracts and summaries of some of the others. (Given the controversy surrounding this topic I didn’t want to suggest just one or two sources, but to show a bit the width of the scientific consensus, and to offer some titbits of related information.) ... 

http://ajstein.tumblr.com/post/40504136918/ ;


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Jennifer Mach's comment, March 30, 2013 9:05 AM
I admit I haven't read this list... but for future reference, I'll definitely have a look.
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Advance in Research on Bacterial Aromatic Extradiol Dioxygenase

As a type of bacterial aromatic ring-cleavage enzymes with versatile functions, extradiol dioxygenases (EDOs) have broad application in the field of environmental protection, chemical synthesis and biotechnologies. This paper reviewed the achievements of EDOs researches including the studies on their classification, catalytic mechanism, the application in biodegradation, biosynthesis, biotechnologies and the novel methods for extracting and modify EDOs. EDOs belong to three evolutionarily independent families, which utilize Fe(II) or Mn(II) as metal ions to catalyze the oxygenolytic fission of aromatic compounds via iron-alkylperoxo intermediates by the incorporation of substrates and O2. Through this mechanism, EDOs possess broad substrates spectra, and often take part in the biosynthesis of active compounds. Meanwhile, EDOs play an important role in the biotechnology such as biosensors. Recently, combined with the technology of metagenomic, hybrid enzymes, more and more EDOs were extracted and modified to provide a general message for the in depth study of EDOs. Fig 5, Ref 32
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Written mostly in chinese, but worth reading (comprehensive biblio)

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Draft genome of the wheat A-genome progenitor Triticum urartu

Draft genome of the wheat A-genome progenitor Triticum urartu | plant cell genetics | Scoop.it

Bread wheat (Triticum aestivum, AABBDD) is one of the most widely cultivated and consumed food crops in the world. However, the complex polyploid nature of its genome makes genetic and functional analyses extremely challenging. The A genome, as a basic genome of bread wheat and other polyploid wheats, for example, T. turgidum (AABB), T. timopheevii (AAGG) and T. zhukovskyi (AAGGAmAm), is central to wheat evolution, domestication and genetic improvement1. The progenitor species of the A genome is the diploid wild einkorn wheat T. urartu2, which resembles cultivated wheat more extensively than do Aegilops speltoides (the ancestor of the B genome3) and Ae. tauschii (the donor of the D genome4), especially in the morphology and development of spike and seed. Here we present the generation, assembly and analysis of a whole-genome shotgun draft sequence of the T. urartu genome. We identified protein-coding gene models, performed genome structure analyses and assessed its utility for analysing agronomically important genes and for developing molecular markers. Our T. urartu genome assembly provides a diploid reference for analysis of polyploid wheat genomes and is a valuable resource for the genetic improvement of wheat.

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A broader perspective on plant domestication and nutrient and carbon cycling

A broader perspective on plant domestication and nutrient and carbon cycling | plant cell genetics | Scoop.it
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Reducing herbivores, supplying nutrients in abundance, and selecting for yield and taste may produce organisms that would never survive in nature. The ecosystem-level effect of the traits of domesticated crops may have some parallels in the natural world, but we should also be prepared to find that ‘survival of the fittest’ in nature and ‘selection for human desires’ may yield asynchronous results for the plant traits that affect C and nutrient cycles.

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Discovery of Genetic Mechanism Allowing Potato Cultivation in Northern Latitudes - Science Daily (press release)

Discovery of Genetic Mechanism Allowing Potato Cultivation in Northern Latitudes - Science Daily (press release) | plant cell genetics | Scoop.it
Discovery of Genetic Mechanism Allowing Potato Cultivation in Northern Latitudes Science Daily (press release) The team of scientists, headed by Wageningen UR Plant Breeding, has published its findings on the gene allowing potato to grow and...
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Jack's curator insight, March 26, 2013 3:56 PM

If these accomplishments and the like in Botany based Genomics were implicated to the full extent could you imagine the effects? Although i understand the viewpoints of those opposed to GMO i think there's just too much of value to throw out such public scares on genetics.

Jack's comment, April 9, 2013 3:47 PM
My thoughts: If these accomplishments and the like in Botany based Genomics were implicated to the full extent could you imagine the effects? Although i understand the viewpoints of those opposed to GMO i think there's just too much of value to throw out such public scares on genetics.
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Quantitative imaging of directional transport through plasmodesmata in moss protonemata via single-cell photoconversion of Dendra2 - Online First - Springer

Quantitative imaging of directional transport through plasmodesmata in moss protonemata via single-cell photoconversion of Dendra2 - Online First - Springer | plant cell genetics | Scoop.it
Cell-to-cell transport of molecules in plants must be properly regulated for plant growth and development. One specialized mechanism that plants have evolved involves transport through plasmodesmata (PD), but when and how transport of molecules via PD is regulated among individual cells remains largely unknown, particularly at the single-cell level. Here, we developed a tool for quantitatively analyzing cell-to-cell transport via PD at a single-cell level using protonemata of Physcomitrella patens and a photoconvertible fluorescent protein, Dendra2. In the filamentous protonemal tissues, one-dimensional intercellular communication can be observed easily. Using this system, we found that Dendra2 was directionally transported toward the apex of the growing protonemata. However, this directional transport could be eliminated by incubation in the dark or treatment with a metabolic inhibitor. Thus, we propose that directional transport of macromolecules can occur via PD in moss protonemata, and may be affected by the photosynthetic and metabolic activity of cells.
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