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Insights into the regenerative property of plant cells and their receptivity to transgenesis: Wheat as a research case study

Insights into the regenerative property of plant cells and their receptivity to transgenesis: Wheat as a research case study | plant cell genetics | Scoop.it
From a holistic perspective, the discovery of cellular plasticity, a very interesting property of totipotency, underlies many topical issues in biology with important medical applications, while transgenesis is a core research tool in biology.

Partially known, some basic mechanisms involved in the regenerative property of cells and in their receptivity to transgenesis are common to plant and animal cells and highlight the principle of the unity of life. Transgenesis provides an important investigative instrument in plant physiology and is regarded as a valuable tool for crop improvement. The economic, social, cultural and scientific importance of cereals has led to a rich stream of research into their genetics, biology and evolution. Sustained efforts to achieve the results obtained in the fields of genetic engineering and applied biotechnology reflect this deep interest. Difficulties encountered in creating genetically modified cereals, especially wheat, highlighted the central notions of tissue culture regeneration and transformation competencies. From the perspective of combining or encountering these competencies in the same cell lineage, this reputedly recalcitrant species provides a stimulating biological system in which to explore the physiological and genetic complexity of both competencies. The former involves two phases, dedifferentiation and redifferentiation. Cells undergo development switches regulated by extrinsic and intrinsic factors. The re-entry into the cell division cycle progressively culminates in the development of organized structures. This is achieved by global chromatin reorganization associated with the reprogramming of the gene expression pattern. The latter is linked with surveillance mechanisms and DNA repair, aimed at maintaining genome integrity before cells move into mitosis, and with those mechanisms aimed at genome expression control and regulation. In order to clarify the biological basis of these two physiological properties and their interconnectedness, we look at both competencies at the core of defense/adaptive mechanisms and survival, between undifferentiated cell proliferation and organization, constituting a transition phase between two different dynamic regimes, a typical feature of critical dynamic systems. Opting for a candidate-gene strategy, several gene families could be proposed as relevant targets for investigating this hypothesis at the molecular level.

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Frontiers | Metabolic engineering of the moss Physcomitrella patens to produce the sesquiterpenoids patchoulol and α/β-santalene | Plant Biotechnology

The moss Physcomitrella patens, has been genetically engineered to produce patchoulol and β-santalene, two valuable sesquiterpenoid ingredients in the fragrance industry. The highest yield of patchoulol achieved was 1.34 mg/g dry weight. This was achieved by non-targeted transformation of the patchoulol synthase and either a yeast or P. patens HMGR gene under the control of a 35S promoter. Santalene synthase targeted to the plastids yielded 0.039 mg/g dry weight of α/β santalene; cytosolic santalene synthase and 35S controlled HMGR afforded 0.022 mg/g dry weight. It has been observed that the final yield of the fragrance molecules is dependent on the expression of the synthase. This is the first report of heterologous production of sesquiterpenes in moss and it opens up a promising source for light-driven production of valuable fragrance ingredients.
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Do Political Attitudes Affect Consumer Choice? Evidence from a Large-Scale Field Study with Genetically Modified Bread in Switzerland

Do Political Attitudes Affect Consumer Choice? Evidence from a Large-Scale Field Study with Genetically Modified Bread in Switzerland | plant cell genetics | Scoop.it
Independent of the left-right model of ideological structure, genetically modified organisms (GMOs) in food and agriculture are resented across the political spectrum in Switzerland. In the absence of any real experience with genetically modified (GM) food but faced with continuous exposure to warning messages in the media, conditioned feelings related to such a politically sensitive product may have a significant influence on revealed consumer choice. In our large-scale field study, we examined this assumption by selling three types of bread labeled as ‘made with organic corn’, ‘made with genetically modified corn’ and ‘made with conventional corn’ respectively in five locations across Switzerland using different price scenarios and selling groups. Customers who decided to buy bread also received an envelope containing a questionnaire about their prior political attitude expressed through their voting decision in a national referendum on a five-year ban on GMOs in 2005. The results demonstrate that consumer purchase decisions are determined by contextual factors not captured by general political attitudes. Surprisingly, the mere presence of GM food did have a positive impact on overall sales. The assumption that consumers would feel turned off by the mere presence of GM food for political reasons can therefore be safely discarded.
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On the Origins of Agriculture

On the Origins of Agriculture | plant cell genetics | Scoop.it
This is the first in a series of posts reviewing the 17 articles found in the October 2014 Special Issue of American Journal of Botany, Speaking of Food: Connecting Basic and Applied Science. Agric...

Via Dorian Q Fuller, Loïc Lepiniec
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Dorian Q Fuller's curator insight, November 21, 7:42 AM

A blog summarizing the recent review on the archaeobotany of agricultural origins, aimed at bringing archaeobotany to a wider botanical audience, by archaeobotanists from Washington University in St Louis.

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#GMO The Precautionary Principle (with Application to the Genetic Modification of Organisms)

#GMO The Precautionary Principle (with Application to the Genetic Modification of Organisms) | plant cell genetics | Scoop.it

We present a non-naive version of the Precautionary (PP) that allows us to avoid paranoia and paralysis by confining precaution to specific domains and problems. PP is intended to deal with uncertainty and risk in cases where the absence of evidence and the incompleteness of scientific knowledge carries profound implications and in the presence of risks of "black swans", unforeseen and unforeseable events of extreme consequence. We formalize PP, placing it within the statistical and probabilistic structure of ruin problems, in which a system is at risk of total failure, and in place of risk we use a formal fragility based approach. We make a central distinction between 1) thin and fat tails, 2) Local and systemic risks and place PP in the joint Fat Tails and systemic cases. We discuss the implications for GMOs (compared to Nuclear energy) and show that GMOs represent a public risk of global harm (while harm from nuclear energy is comparatively limited and better characterized). PP should be used to prescribe severe limits on GMOs.

Jean-Pierre Zryd's insight:

The authors consider GMO as a high risk technology - Their article mentionned mostly if not only highly controversial and discredited GMO studies (Seralani among others) - This of course invalidate their conclusions.

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DNA Analysis of Herbarium Specimens of the Grass Weed Alopecurus myosuroides Reveals Herbicide Resistance Pre-Dated Herbicides

DNA Analysis of Herbarium Specimens of the Grass Weed Alopecurus myosuroides Reveals Herbicide Resistance Pre-Dated Herbicides | plant cell genetics | Scoop.it
Acetyl-CoA carboxylase (ACCase) alleles carrying one point mutation that confers resistance to herbicides have been identified in arable grass weed populations where resistance has evolved under the selective pressure of herbicides. In an effort to determine whether herbicide resistance evolves from newly arisen mutations or from standing genetic variation in weed populations, we used herbarium specimens of the grass weed Alopecurus myosuroides to seek mutant ACCase alleles carrying an isoleucine-to-leucine substitution at codon 1781 that endows herbicide resistance. These specimens had been collected between 1788 and 1975, i.e., prior to the commercial release of herbicides inhibiting ACCase. Among the 734 specimens investigated, 685 yielded DNA suitable for PCR. Genotyping the ACCase locus using the derived Cleaved Amplified Polymorphic Sequence (dCAPS) technique identified one heterozygous mutant specimen that had been collected in 1888. Occurrence of a mutant codon encoding a leucine residue at codon 1781 at the heterozygous state was confirmed in this specimen by sequencing, clearly demonstrating that resistance to herbicides can pre-date herbicides in weeds. We conclude that point mutations endowing resistance to herbicides without having associated deleterious pleiotropic effects can be present in weed populations as part of their standing genetic variation, in frequencies higher than the mutation frequency, thereby facilitating their subsequent selection by herbicide applications.
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Does polyploidy facilitate long-distance dispersal?

Does polyploidy facilitate long-distance dispersal? | plant cell genetics | Scoop.it

Background and Aims The ability of plant lineages to reach all continents contributes substantially to their evolutionary success. This is exemplified by the Poaceae, one of the most successful angiosperm families, in which most higher taxa (tribes, subfamilies) have global distributions. Due to the old age of the ocean basins relative to the major angiosperm radiations, this is only possible by means of long-distance dispersal (LDD), yet the attributes of lineages with successful LDD remain obscure. Polyploid species are over-represented in invasive floras and in the previously glaciated Arctic regions, and often have wider ecological tolerances than diploids; thus polyploidy is a candidate attribute of successful LDD.

Methods The link between polyploidy and LDD was explored in the globally distributed grass subfamily Danthonioideae. An almost completely sampled and well-resolved species-level phylogeny of the danthonioids was used, and the available cytological information was assembled. The cytological evolution in the clade was inferred using maximum likelihood (ML) as implemented in ChromEvol. The biogeographical evolution in the clade was reconstructed using ML and Bayesian approaches.

Key Results Numerous increases in ploidy level are demonstrated. A Late Miocene–Pliocene cycle of polyploidy is associated with LDD, and in two cases (the Australian Rytidosperma and the American Danthonia) led to secondary polyploidy. While it is demonstrated that successful LDD is more likely in polyploid than in diploid lineages, a link between polyploidization events and LDD is not demonstrated.

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A Meta-Analysis of the Impacts of Genetically Modified Crops - Klümper & Qaim (2014) - PLOS One

A Meta-Analysis of the Impacts of Genetically Modified Crops - Klümper & Qaim (2014) - PLOS One | plant cell genetics | Scoop.it

Despite the rapid adoption of genetically modified (GM) crops by farmers in many countries, controversies about this technology continue. Uncertainty about GM crop impacts is one reason for widespread public suspicion. 

 

We carry out a meta-analysis of the agronomic and economic impacts of GM crops to consolidate the evidence... Studies were included when they build on primary data from farm surveys or field trials anywhere in the world, and when they report impacts of GM soybean, maize, or cotton on crop yields, pesticide use, and/or farmer profits... 

 

 

On average, GM technology adoption has reduced chemical pesticide use by 37%, increased crop yields by 22%, and increased farmer profits by 68%. Yield gains and pesticide reductions are larger for insect-resistant crops than for herbicide-tolerant crops. Yield and profit gains are higher in developing countries than in developed countries...


The meta-analysis reveals robust evidence of GM crop benefits for farmers in developed and developing countries. Such evidence may help to gradually increase public trust in this technology.

 

http://dx.doi.org/10.1371/journal.pone.0111629

 


Via Alexander J. Stein
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AckerbauHalle's curator insight, November 4, 4:52 PM

Meta-Analyse zum Einsatz von transgenen Pflanzen

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Speaking of food: Connecting basic and applied plant science

Speaking of food: Connecting basic and applied plant science | plant cell genetics | Scoop.it

The Food and Agriculture Organization (FAO) predicts that food production must rise 70% over the next 40 years to meet the demands of a growing population that is expected to reach nine billion by the year 2050. Many facets of basic plant science promoted by the Botanical Society of America are important for agriculture; however, more explicit connections are needed to bridge the gap between basic and applied plant research. This special issue, Speaking of Food: Connecting Basic and Applied Plant Science, was conceived to showcase productive overlaps of basic and applied research to address the challenges posed by feeding billions of people and to stimulate more research, fresh connections, and new paradigms. Contributions to this special issue thus illustrate some interactive areas of study in plant science—historical and modern plant–human interaction, crop and weed origins and evolution, and the effects of natural and artificial selection on crops and their wild relatives. These papers provide examples of how research integrating the basic and applied aspects of plant science benefits the pursuit of knowledge and the translation of that knowledge into actions toward sustainable production of crops and conservation of diversity in a changing climate.

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China's GMO Stockpile - MIT Technology Review

China's GMO Stockpile - MIT Technology Review | plant cell genetics | Scoop.it
With its world-leading research investments and vast size, China will dominate the future of genetically modified food—despite the resistance of its population.
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Exploration of Three Solanum Species for Improvement of Antioxidant Traits in Tomato

Exploration of Three Solanum Species for Improvement of Antioxidant Traits in Tomato | plant cell genetics | Scoop.it
Wild tomato species have been widely used for improvement of tomato disease resistance but have not been extensively explored for health-related traits. In this work, three interspecific populations derived from backcrosses between cultivated tomato and Solanum pimpinellifolium (LA1589), S. habrochaites (LA1223), and S. peruvianum (LA2172) were analyzed for water-soluble antioxidant activity, phenolic content, vitamin C content, and basic agronomic traits including fruit weight, shape, and color. The wild species accessions significantly exceeded S. lycopersicum for all three antioxidant traits with only one exception: vitamin C content in S. habrochaites LA1223. Several populations and traits showed transgressive segregation indicating that the backcross populations contained individuals with allele combinations that allowed antioxidant activity/content to exceed that of both parents. The S. habrochaites LA1223 population provided the best starting material for improvement of water-soluble antioxidant activity and phenolics content with 20% and 15% of the population, respectively, significantly exceeding the parental values for these traits. Moreover, the S. habrochaites population contained individuals that had nearly 2-fold more water-soluble antioxidant activity and phenolic content than cultivated tomato. The S. peruvianum LA2172 population was best for improvement of vitamin C content with 3-fold variation for the trait and individuals, which had twice as much vitamin C as cultivated tomato.
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Genome-wide identification and characterisation of R2R3-MYB genes in sugar beet (Beta vulgaris)

Genome-wide identification and characterisation of R2R3-MYB genes in sugar beet (Beta vulgaris) | plant cell genetics | Scoop.it
Background

The R2R3-MYB genes comprise one of the largest transcription factor gene families in plants, playing regulatory roles in plant-specific developmental processes, metabolite accumulation and defense responses. Although genome-wide analysis of this gene family has been carried out in some species, the R2R3-MYB genes in Beta vulgaris ssp. vulgaris (sugar beet) as the first sequenced member of the order Caryophyllales, have not been analysed heretofore.

Results

We present a comprehensive, genome-wide analysis of the MYB genes from Beta vulgaris ssp. vulgaris (sugar beet) which is the first species of the order Caryophyllales with a sequenced genome. A total of 70 R2R3-MYB genes as well as genes encoding three other classes of MYB proteins containing multiple MYB repeats were identified and characterised with respect to structure and chromosomal organisation. Also, organ specific expression patterns were determined from RNA-seq data. The R2R3-MYB genes were functionally categorised which led to the identification of a sugar beet-specific clade with an atypical amino acid composition in the R3 domain, putatively encoding betalain regulators. The functional classification was verified by experimental confirmation of the prediction that the R2R3-MYB gene Bv_iogq encodes a flavonol regulator.

Conclusions

This study provides the first step towards cloning and functional dissection of the role of MYB transcription factor genes in the nutritionally and evolutionarily interesting species B. vulgaris. In addition, it describes the flavonol regulator BvMYB12, being the first sugar beet R2R3-MYB with an experimentally proven function.

 

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RAD51B plays an essential role during somatic and meiotic recombination in Physcomitrella

RAD51B plays an essential role during somatic and meiotic recombination in Physcomitrella | plant cell genetics | Scoop.it

The eukaryotic RecA homologue Rad51 is a key factor in homologous recombination and recombinational repair. Rad51-like proteins have been identified in yeast (Rad55, Rad57 and Dmc1), plants and vertebrates (RAD51B, RAD51C, RAD51D, XRCC2, XRCC3 and DMC1). RAD51 and DMC1 are the strand-exchange proteins forming a nucleofilament for strand invasion, however, the function of the paralogues in the process of homologous recombination is less clear. In yeast the two Rad51 paralogues, Rad55 and Rad57, have been shown to be involved in somatic and meiotic HR and they are essential to the formation of the Rad51/DNA nucleofilament counterbalancing the anti-recombinase activity of the SRS2 helicase. Here, we examined the role of RAD51B in the model bryophyte Physcomitrella patens. Mutant analysis shows that RAD51B is essential for the maintenance of genome integrity, for resistance to DNA damaging agents and for gene targeting. Furthermore, we set up methods to investigate meiosis in Physcomitrella and we demonstrate that the RAD51B protein is essential for meiotic homologous recombination. Finally, we show that all these functions are independent of the SRS2 anti-recombinase protein, which is in striking contrast to what is found in budding yeast where the RAD51 paralogues are fully dependent on the SRS2 anti-recombinase function.

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Scientific Reports: Secret lifestyles of Neurospora crassa: can it be a plant pathogen? (2014)

Scientific Reports: Secret lifestyles of Neurospora crassa: can it be a plant pathogen? (2014) | plant cell genetics | Scoop.it

Neurospora crassa has a long history as an excellent model for genetic, cellular, and biochemical research. Although this fungus is known as a saprotroph, it normally appears on burned vegetations or trees after forest fires. However, due to a lack of experimental evidence, the nature of its association with living plants remains enigmatic. Here we report that Scots pine (Pinus sylvestris) is a host plant for N. crassa. The endophytic lifestyle of N. crassa was found in its interaction with Scots pine. Moreover, the fungus can switch to a pathogenic state when its balanced interaction with the host is disrupted. Our data reveal previously unknown lifestyles of N. crassa, which are likely controlled by both environmental and host factors. Switching among the endophytic, pathogenic, and saprotrophic lifestyles confers upon fungi phenotypic plasticity in adapting to changing environments and drives the evolution of fungi and associated plants.


Via Kamoun Lab @ TSL
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Forschungsarbeit "The German Beekeepers and Modern Plant Biotechnology" (english) von Klaus-Dieter Jany / Eberhard Höfer, Verlag Dr. Kovač, Hamburg 2015

Genetic engineering – an emotive issue in Germany. Only few topics in the agriculture and food sector are so emotionally and controversially discussed as modern plant biotechnology; the cultivation of genetically modified plants and their use as food or feed. Large circles of society are skeptical or fundamentally oppose the application of this technology. The reasons are manifold: ethical concerns, unforeseen risks to human and environment, threat of natural and organic farming and fears of economic loss. Parts of the beekeepers see in modern plant biotechnology a sustainable threat to their existence, and fear that the entry of pollen derived from genetically modified plants in honey reduces the acceptance of German honey amongst consumers and that Bt toxins affect the health of bees. The book presents a chronological overview of the fight and measures by beekeepers to enforce a ban on the cultivation of GM plants in Germany and to enforce a legal claim for compensation for economic losses caused by GM pollen in honey. The development of one simple compensation process and its transition to the European Court of Justice (ECJ) is shown and critically discussed. The ECJ judgment led to a revision of the EU-Honey Directive. As beekeepers did not feel adequately protected by the state, they carried out destructions of fields planted with GM crops as a means of civil disobedience. In the end, neither the processes nor the field destructions led to a ban of modern plant biotechnology or to a compensation claim or to a labeling of honey containing traces of GM pollen.

In the second part of the book, the scientific literature was analyzed regarding the impact of Bt toxins and Bt pollen on bee health. From the numerous scientific investigations and obtained results, no negative effect of Bt toxins / Bt-plants on the health of bees or bee mortality can be concluded.
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Speaking of food: Connecting basic and applied plant science

Speaking of food: Connecting basic and applied plant science | plant cell genetics | Scoop.it
The Food and Agriculture Organization (FAO) predicts that food production must rise 70% over the next 40 years to meet the demands of a growing population that is expected to reach nine billion by the year 2050. Many facets of basic plant science promoted by the Botanical Society of America are important for agriculture; however, more explicit connections are needed to bridge the gap between basic and applied plant research. This special issue, Speaking of Food: Connecting Basic and Applied Plant Science, was conceived to showcase productive overlaps of basic and applied research to address the challenges posed by feeding billions of people and to stimulate more research, fresh connections, and new paradigms. Contributions to this special issue thus illustrate some interactive areas of study in plant science—historical and modern plant–human interaction, crop and weed origins and evolution, and the effects of natural and artificial selection on crops and their wild relatives. These papers provide examples of how research integrating the basic and applied aspects of plant science benefits the pursuit of knowledge and the translation of that knowledge into actions toward sustainable production of crops and conservation of diversity in a changing climate.
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Maize Pests in Mexico and Challenges for the Adoption of Integrated Pest Management Programs

Mexico is the fifth largest maize producer and the area of origin and domestication of this crop. Mexico’s 6.8 million hectare annual production of maize represents 30% of its total domestic agricultural production and 6.6% of the country’s arable land. However, Mexico’s average yield of 3.17 tons per hectare is 38% below the world’s average. Although maize is a major crop globally, it is typically not grown under modern or comprehensive integrated pest management (IPM) programs aimed at minimizing economic damage and lowering environmental and health risks. Pest management in commercial maize in Mexico continues to rely primarily on chemical control using conventional synthetic insecticides. Approximately 3,000 tons of active ingredient per year are used to combat the single most important pest, the fall armyworm (Spodoptera frugiperda Smith), followed by the corn earworm (Helicoverpa zea Boddie) and the black cutworm (Agrotis ipsilon (Hufnagel)). Mexican farmers have successfully adopted IPM programs for many crops, but IPM is not common in maize crops. Although different components and elements have been identified, most of the information on maize pests and IPM in Mexico has been published in technical bulletins of a reduced regional scope or in difficult-to-access reports, generally describing laboratory screenings, preliminary field evaluations, or listing technical recommendations but rarely including products and practices that growers actually use. This report provides up-to-date information on the common pests in the main maize-growing areas of Mexico from experts in the field. Updated information on maize pest population dynamics and control has been gathered from agricultural professionals directly involved in maize crop protection. This critical information, not readably available for Mexican production systems, is intended to help researchers, government officials, and industry specialists in making decisions regarding time and resource allocations in the design and implementation of IPM techniques, practices, and programs for Mexican maize.
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Epigenetic reprogramming in plant sexual reproduction : Nature Reviews Genetics : Nature Publishing Group

Epigenetic reprogramming in plant sexual reproduction : Nature Reviews Genetics : Nature Publishing Group | plant cell genetics | Scoop.it
Epigenetic reprogramming consists of global changes in DNA methylation and histone modifications. In mammals, epigenetic reprogramming is primarily associated with sexual reproduction and occurs during both gametogenesis and early embryonic development. Such reprogramming is crucial not only to maintain genomic integrity through silencing transposable elements but also to reset the silenced status of imprinted genes. In plants, observations of stable transgenerational inheritance of epialleles have argued against reprogramming. However, emerging evidence supports that epigenetic reprogramming indeed occurs during sexual reproduction in plants and that it has a major role in maintaining genome integrity and a potential contribution to epiallelic variation.
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Agroecological Research: Conforming—or Transforming the Dominant Agro-Food Regime?

Agroecological Research: Conforming—or Transforming the Dominant Agro-Food Regime? | plant cell genetics | Scoop.it
Agroecology has three practical forms—a scientific discipline, an agricultural practice, and a social movement. Their integration has provided a collective-action mode for contesting the dominant agro-food regime and creating alternatives, especially through a linkage with food sovereignty. At the same time, agroecology has been recently adopted by some actors who also promote conventional agriculture. Agroecology can play different roles—either conforming to the dominant regime, or else helping to transform it—contingent on specific empowerment strategies. Tensions between “conform versus transform” roles can be identified in European agroecological research, especially in three areas: farm-level agroecosystems development; participatory plant breeding; and short food-supply chains remunerating agroecological methods. To play a transformative role, collaborative strategies need to go beyond the linear stereotype whereby scientists “transfer” technology or farmers “apply” scientific research results. To the extent that farmer–scientist alliances co-create and exchange knowledge, such gains can transform the research system.
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RAD51B plays an essential role during somatic and meiotic recombination in Physcomitrella

RAD51B plays an essential role during somatic and meiotic recombination in Physcomitrella | plant cell genetics | Scoop.it
The eukaryotic RecA homologue Rad51 is a key factor in homologous recombination and recombinational repair. Rad51-like proteins have been identified in yeast (Rad55, Rad57 and Dmc1), plants and vertebrates (RAD51B, RAD51C, RAD51D, XRCC2, XRCC3 and DMC1). RAD51 and DMC1 are the strand-exchange proteins forming a nucleofilament for strand invasion, however, the function of the paralogues in the process of homologous recombination is less clear. In yeast the two Rad51 paralogues, Rad55 and Rad57, have been shown to be involved in somatic and meiotic HR and they are essential to the formation of the Rad51/DNA nucleofilament counterbalancing the anti-recombinase activity of the SRS2 helicase. Here, we examined the role of RAD51B in the model bryophyte Physcomitrella patens. Mutant analysis shows that RAD51B is essential for the maintenance of genome integrity, for resistance to DNA damaging agents and for gene targeting. Furthermore, we set up methods to investigate meiosis in Physcomitrella and we demonstrate that the RAD51B protein is essential for meiotic homologous recombination. Finally, we show that all these functions are independent of the SRS2 anti-recombinase protein, which is in striking contrast to what is found in budding yeast where the RAD51 paralogues are fully dependent on the SRS2 anti-recombinase function.
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BMC Plant Biology | Full text | Dynamic parent-of-origin effects on small interfering RNA expression in the developing maize endosperm

BMC Plant Biology | Full text | Dynamic parent-of-origin effects on small interfering RNA expression in the developing maize endosperm | plant cell genetics | Scoop.it
In angiosperms, the endosperm plays a crucial placenta-like role in that not only is it necessary for nurturing the embryo, but also regulating embryogenesis through complicated genetic and epigenetic interactions with other seed compartments and is the primary tissue in which genomic imprinting occurs.
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Building a bridge from basic botany to applied agriculture - Phys.Org

Building a bridge from basic botany to applied agriculture - Phys.Org | plant cell genetics | Scoop.it
One of the planet's leading questions is how to produce enough food to feed the world in an increasingly variable climate.
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Plant root exudates mediate neighbour recognition and trigger complex behavioural changes -

Plant root exudates mediate neighbour recognition and trigger complex behavioural changes - | plant cell genetics | Scoop.it
Some plant species are able to distinguish between neighbours of different genetic identity and attempt to pre-empt resources through root proliferation in the presence of unrelated competitors, but avoid competition with kin. However, studies on neighbour recognition have met with some scepticism because the mechanisms by which plants identify their neighbours have remained unclear.
In order to test whether root exudates could mediate neighbour recognition in plants, we performed a glasshouse experiment in which plants of Deschampsia caespitosa were subjected to root exudates collected from potential neighbours of different genetic identities, including siblings and individuals belonging to the same or a different population or species.
Our results show that root exudates can carry specific information about the genetic relatedness, population origin and species identity of neighbours, and trigger different responses at the whole root system level and at the level of individual roots in direct contact with locally applied exudates. Increased root density was mainly achieved through changes in morphology rather than biomass allocation, suggesting that plants are able to limit the energetic cost of selfish behaviour.
This study reveals a new level of complexity in the ability of plants to interpret and react to their surroundings.

Via Christophe Jacquet
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Genetic Analysis of DEFECTIVE KERNEL1 Loop Function in Three-Dimensional Body Patterning in Physcomitrella patens

Genetic Analysis of DEFECTIVE KERNEL1 Loop Function in Three-Dimensional Body Patterning in Physcomitrella patens | plant cell genetics | Scoop.it
In this article, we continue to explore the separate DEK1 domains, focusing on the Loop region. First, using homologous recombination, we create a P. patens Loop deletion mutant, dek1Δloop. On the basis of phylogenetic analysis of Loop sequences from Charophyta and land plant species, we use Loop coding regions from Marchantia polymorpha, maize, and Arabidopsis to complement the dek1Δloop mutant in P. patens in order to study the functional conservation of Loop sequences from land plants. Bioinformatics analysis is used to re-examine the structure of DEK1 MEM in order to identify homologous proteins or protein domains that help elucidate the MEM function. Next, in order to develop a better understanding of the global role of DEK1, we use RNA sequencing (RNA-Seq) differential expression analysis to study the effect of DEK1 on the transcriptome of P. patens by comparing wild-type and Δdek1 protonemata before and after bud initiation. Finally, we use novel data to identify the last charophycean species of green algae that possessed multiple calpain forms before retention of DEK1 as the single calpain of land plants.
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RAD51B plays an essential role during somatic and meiotic recombination in Physcomitrella

RAD51B plays an essential role during somatic and meiotic recombination in Physcomitrella | plant cell genetics | Scoop.it

The eukaryotic RecA homologue Rad51 is a key factor in homologous recombination and recombinational repair. Rad51-like proteins have been identified in yeast (Rad55, Rad57 and Dmc1), plants and vertebrates (RAD51B, RAD51C, RAD51D, XRCC2, XRCC3 and DMC1). RAD51 and DMC1 are the strand-exchange proteins forming a nucleofilament for strand invasion, however, the function of the paralogues in the process of homologous recombination is less clear. In yeast the two Rad51 paralogues, Rad55 and Rad57, have been shown to be involved in somatic and meiotic HR and they are essential to the formation of the Rad51/DNA nucleofilament counterbalancing the anti-recombinase activity of the SRS2 helicase. Here, we examined the role of RAD51B in the model bryophyte Physcomitrella patens. Mutant analysis shows that RAD51B is essential for the maintenance of genome integrity, for resistance to DNA damaging agents and for gene targeting. Furthermore, we set up methods to investigate meiosis in Physcomitrella and we demonstrate that the RAD51B protein is essential for meiotic homologous recombination. Finally, we show that all these functions are independent of the SRS2 anti-recombinase protein, which is in striking contrast to what is found in budding yeast where the RAD51 paralogues are fully dependent on the SRS2 anti-recombinase function.

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Scooped by Jean-Pierre Zryd
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Systemic Spread and Propagation of a Plant-Pathogenic Virus in European Honeybees, Apis mellifera

Systemic Spread and Propagation of a Plant-Pathogenic Virus in European Honeybees, Apis mellifera | plant cell genetics | Scoop.it

Emerging and reemerging diseases that result from pathogen host shifts are a threat to the health of humans and their domesticates. RNA viruses have extremely high mutation rates and thus represent a significant source of these infectious diseases. In the present study, we showed that a plant-pathogenic RNA virus, tobacco ringspot virus (TRSV), could replicate and produce virions in honeybees, Apis mellifera, resulting in infections that were found throughout the entire body. Additionally, we showed that TRSV-infected individuals were continually present in some monitored colonies. While intracellular life cycle, species-level genetic variation, and pathogenesis of the virus in honeybee hosts remain to be determined, the increasing prevalence of TRSV in conjunction with other bee viruses from spring toward winter in infected colonies was associated with gradual decline of host populations and winter colony collapse, suggesting the negative impact of the virus on colony survival. Furthermore, we showed that TRSV was also found in ectoparasitic Varroa mites that feed on bee hemolymph, but in those instances the virus was restricted to the gastric cecum of Varroa mites, suggesting that Varroa mites may facilitate the spread of TRSV in bees but do not experience systemic invasion. Finally, our phylogenetic analysis revealed that TRSV isolates from bees, bee pollen, and Varroa mites clustered together, forming a monophyletic clade. The tree topology indicated that the TRSVs from arthropod hosts shared a common ancestor with those from plant hosts and subsequently evolved as a distinct lineage after transkingdom host alteration. This study represents a unique example of viruses with host ranges spanning both the plant and animal kingdoms.

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