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PLOS ONE: Sex in Cheese: Evidence for Sexuality in the Fungus Penicillium roqueforti

PLOS ONE: Sex in Cheese: Evidence for Sexuality in the Fungus Penicillium roqueforti | plant cell genetics | Scoop.it

Although most eukaryotes reproduce sexually at some moment of their life cycle, as much as a fifth of fungal species were thought to reproduce exclusively asexually. Nevertheless, recent studies have revealed the occurrence of sex in some of these supposedly asexual species. For industrially relevant fungi, for which inoculums are produced by clonal-subcultures since decades, the potentiality for sex is of great interest for strain improvement strategies. Here, we investigated the sexual capability of the fungus Penicillium roqueforti, used as starter for blue cheese production. We present indirect evidence suggesting that recombination could be occurring in this species. The screening of a large sample of strains isolated from diverse substrates throughout the world revealed the existence of individuals of both mating types, even in the very same cheese. The MAT genes, involved in fungal sexual compatibility, appeared to evolve under purifying selection, suggesting that they are still functional. The examination of the recently sequenced genome of the FM 164 cheese strain enabled the identification of the most important genes known to be involved in meiosis, which were found to be highly conserved. Linkage disequilibria were not significant among three of the six marker pairs and 11 out of the 16 possible allelic combinations were found in the dataset. Finally, the detection of signatures of repeat induced point mutations (RIP) in repeated sequences and transposable elements reinforces the conclusion that P. roqueforti underwent more or less recent sex events. In this species of high industrial importance, the induction of a sexual cycle would open the possibility of generating new genotypes that would be extremely useful to diversify cheese products

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The Interrelationships of Land Plants and the Nature of the Ancestral Embryophyte

The Interrelationships of Land Plants and the Nature of the Ancestral Embryophyte | plant cell genetics | Scoop.it

• Early land plant relationships are extremely uncertain • We resolve the “Setaphyta” clade of liverworts plus mosses • The simple body plan of liverworts results from loss of ancestral characters • The ancestral land plant was more complex

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Why a global decline in genetic crop variety matters for the future of food

Why a global decline in genetic crop variety matters for the future of food | plant cell genetics | Scoop.it
Preserving the genetic diversity of edible plants could help us develop new crop varieties, with useful traits such as drought and disease-resistance.
Via Luigi Guarino
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Phytoglobin expression influences soil flooding response of corn plants | Annals of Botany | Oxford Academic

Phytoglobin expression influences soil flooding response of corn plants | Annals of Botany | Oxford Academic | plant cell genetics | Scoop.it
Excess water is a limiting factor for crop productivity. Under conditions of full submergence or flooding, plants can experience prolonged oxygen depletion which compromises basic physiological and biochemical processes. Severe perturbations of the photosynthetic machinery with a concomitant decline in photosynthetic potential as a result of elevated levels of reactive oxygen species (ROS) are the major consequences of water excess. Phytoglobins (Pgbs) are ubiquitous proteins induced by several types of stress which affect plant response by modulating nitric oxide.
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Reduction in Root Secondary Growth as a Strategy for Phosphorus Acquisition

Reduction in Root Secondary Growth as a Strategy for Phosphorus Acquisition | plant cell genetics | Scoop.it
We tested the hypothesis that reduced root secondary growth of dicotyledonous species improves phosphorus acquisition. Functional-structural modeling in SimRoot indicates that, in common bean (Phaseolus vulgaris), reduced root secondary growth reduces root metabolic costs, increases root length, improves phosphorus capture, and increases shoot biomass in low-phosphorus soil. Observations from the field and greenhouse confirm that, under phosphorus stress, resource allocation is shifted from secondary to primary root growth, genetic variation exists for this response, and reduced secondary growth improves phosphorus capture from low-phosphorus soil. Under low phosphorus in greenhouse mesocosms, genotypes with reduced secondary growth had 39% smaller root cross-sectional area, 60% less root respiration, 27% greater root length, 78% greater shoot phosphorus content, and 68% greater shoot mass than genotypes with advanced secondary growth. In the field under low phosphorus, these genotypes had 43% smaller root cross-sectional area, 32% greater root length, 58% greater shoot phosphorus content, and 80% greater shoot mass than genotypes with advanced secondary growth. Secondary growth eliminated arbuscular mycorrhizal associations as cortical tissue was destroyed. These results support the hypothesis that reduced root secondary growth is an adaptive response to low phosphorus availability and merits investigation as a potential breeding target.
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Why the European Union needs a national GMO opt-in mechanism

On March 27, 2017, the European Union (EU; Brussels) Appeal Committee on Genetically Modified Food and Feed and Environmental Risk voted on draft regulations for approving the placement of three genetically modified (GM) maize events on the market for cultivation in the EU1. The Appeal Committee once again did not reach a qualified majority for either approval or rejection. The March vote result was similar to the preceding vote in the Regulatory Committee 2001/18/EC on January 27, 2017 (ref. 2). This case was the first of its kind since the amendment of the EU legislation on GM crop cultivation (Directive 2015/412, the so-called 'opt-out Directive')3 came into force in 2015. The opt-out Directive allows EU member states to restrict or prohibit cultivation of GM crops in their territory based on “compelling grounds such as those related to: (a) environmental policy objectives; (b) town and country planning; (c) land use; (d) socioeconomic impacts; (e) avoidance of GMO presence in other products [e.g. crops that would be subject to cross-border 'contamination']; (f) agricultural policy objectives; and (g) public policy”3. This possibility was introduced to acknowledge that decisions on the cultivation of GM crops raise complicated issues other than safety, which are best dealt with at a national level and also to improve the process for authorizing GM crops in the EU.

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Jonathan Lapleau's curator insight, January 11, 9:20 AM
We need to improve the European regulatory system for GMO, this letter explain why and how.
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ScienceDirect

ScienceDirect | plant cell genetics | Scoop.it
Highlights • Two novel methods were combined to estimate a realistic worst case hazard index for pesticide residues in the Danish population. • The methods were able to refine previous estimates especially with regard to below LOQ (left censored) data. • Cumulative health risk assessment conducted for the Danish population. • Perspectives on hazard level of pesticides; comparisons with mycotoxins, caffeine and alcohol. Abstract Relatively few studies are available on realistic cumulative risk assessments for dietary pesticide exposure. Despite available studies showing low risk, public concern remains. A method to estimate realistic residue levels based on information from spraying journals and supervised residue trials was described in a previous publication. The present article proposes a new method to estimate average residue levels in imported foods based on residue monitoring data and knowledge about agronomic practices. The two methods were used in combination to estimate average pesticide residue levels in 47 commodities on the Danish market. The chronic consumer exposure was estimated in six Danish diets. The Hazard Index (HI) method was used to assess consumer risk. Despite the conservative (cautious) risk assessment approach, low HI values where obtained. The HI was 16% for adults and 44% for children, combining the risk of all pesticides in the diet. Conclusion: the present study adds support to the evidence showing that adverse health effects of chronic pesticide residue exposure in the Danish population are very unlikely. The HI for pesticides for a Danish adult was on level with that of alcohol for a person consuming the equivalent of 1 glass of wine every seventh year.
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Transgenic Bt cotton expressing Cry1Ac/Cry2Ab or Cry1Ac/EPSPS does not affect the plant bug Adelphocoris suturalis or the pollinating beetle Haptoncus luteolus - Env Pollution (2017) 

Transgenic Bt cotton expressing Cry1Ac/Cry2Ab or Cry1Ac/EPSPS does not affect the plant bug Adelphocoris suturalis or the pollinating beetle Haptoncus luteolus - Env Pollution (2017)  | plant cell genetics | Scoop.it
The widespread cultivation of transgenic Bt cotton makes assessing the potential effects of this recombinant crop on non-target organisms a priority... The plant bug Adelphocoris suturalis is now a major pest of cotton in southern China and the beetle Haptoncus luteolus is one of the most ancient cotton pollinators. 

We conducted laboratory experiments to evaluate the toxicity of the Bt cotton varieties ZMSJ, which expresses the toxins Cry1Ac and Cry2Ab, and ZMKCKC, which expresses Cry1Ac and EPSPS, on adult A. suturalis and H. luteolus. 

No significant increase in the mortality of either species was detected after feeding on Bt cotton leaves or pollen for 7 days. Trace amounts of Cry1Ac and Cry2Ab proteins could be detected in both species but in vitro binding experiments found no evidence of Cry1Ac and Cry2Ab binding proteins. 

These results demonstrate that feeding on the leaves or pollen of these two Bt cotton varieties has no toxic effects on adult A. suturalis or H. luteolus. 



Via Alexander J. Stein
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Crop Science Abstract - Crop Breeding & Genetics Isolation of Mutations Conferring Increased Glyphosate Resistance in Spring Wheat | Digital Library

A mutation breeding approach was used to explore the feasibility of isolating glyphosate-resistant (GR) wheat (Triticum aestivum L.) lines. Although transgenic GR wheat cultivars were developed, they were never introduced due to lack of consumer acceptance and concern over management of volunteer wheat in rotation. Large-scale screening experiments recovered ethyl methanesulfonate mutants able to resist 360 to 480 g acid equivalent (ae) ha−1 glyphosate in four spring wheat cultivars, ‘Hollis’, ‘Louise’, ‘Macon’, and ‘Tara2002’, indicating that it is possible to recover resistance in a wide range of genetic backgrounds (glyphosate is typically applied at 840 g ae ha−1 in transgenic crops). Glyphosate rates of 420 to 530 g ae ha−1 were sufficient to kill the susceptible wild-type parents. Seven GR mutants were characterized: GRH9-5, GRH9-8, GRL1, GRL33, GRL65, GRM14, and GRT20. Glyphosate resistance was examined at the whole-plant level in dose–response experiments. Three mutant lines—GRL33, GRH9-5, and GRT20—exhibited resistance based on a significant increase in the dose required to retard growth compared with the corresponding susceptible wild type. According to F2 segregation analysis, GRL1, GRL65, and GRT20 segregated as a single dominant gene, whereas GRL33, GRH9-5, and GRH9-8 appeared to be either a single semidominant or polygenic trait. Although GRL1 was associated with an amino acid substitution (L239F) in TaEPSPS-7D1, no nucleotide changes were observed in the coding regions of wheat 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene in GRL33 and GRH9-8. Results suggest that glyphosate resistance can result from multiple genetic mechanisms in wheat.
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Anaesthetics stop diverse plant organ movements, affect endocytic vesicle recycling and ROS homeostasis, and block action potentials in Venus flytraps | Annals of Botany | Oxford Academic

Anaesthetics stop diverse plant organ movements, affect endocytic vesicle recycling and ROS homeostasis, and block action potentials in Venus flytraps | Annals of Botany | Oxford Academic | plant cell genetics | Scoop.it

Abstract Background and Aims Anaesthesia for medical purposes was introduced in the 19th century. However, the physiological mode of anaesthetic drug actions on the nervous system remains unclear. One of the remaining questions is how these different compounds, with no structural similarities and even chemically inert elements such as the noble gas xenon, act as anaesthetic agents inducing loss of consciousness. The main goal here was to determine if anaesthetics affect the same or similar processes in plants as in animals and humans. Methods A single-lens reflex camera was used to follow organ movements in plants before, during and after recovery from exposure to diverse anaesthetics. Confocal microscopy was used to analyse endocytic vesicle trafficking. Electrical signals were recorded using a surface AgCl electrode. Key Results Mimosa leaves, pea tendrils, Venus flytraps and sundew traps all lost both their autonomous and touch-induced movements after exposure to anaesthetics. In Venus flytrap, this was shown to be due to the loss of action potentials under diethyl ether anaesthesia. The same concentration of diethyl ether immobilized pea tendrils. Anaesthetics also impeded seed germination and chlorophyll accumulation in cress seedlings. Endocytic vesicle recycling and reactive oxygen species (ROS) balance, as observed in intact Arabidopsis root apex cells, were also affected by all anaesthetics tested. Conclusions Plants are sensitive to several anaesthetics that have no structural similarities. As in animals and humans, anaesthetics used at appropriate concentrations block action potentials and immobilize organs via effects on action potentials, endocytic vesicle recycling and ROS homeostasis. Plants emerge as ideal model objects to study general questions related to anaesthesia, as well as to serve as a suitable test system for human anaesthesia.

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Meta-analysis approach to assess effect of tillage on microbial biomass and enzyme activities

Meta-analysis approach to assess effect of tillage on microbial biomass and enzyme activities | plant cell genetics | Scoop.it
Measures of soil biology are critical for the assessment of soil quality under different agricultural management practices. By modifying soil microclimate, tillage exerts the most important control on soil microbial communities. The objective of this study is to assess the effect of tillage on soil microbial biomass and enzyme activities. A meta-analysis was conducted utilizing 139 observations from 62 studies from around the world; the selected effect size (ES) was logn of the response ratio (RR), the mean of the tilled treatment divided by the mean of the no-till control. This ES was calculated for seven different microbial properties – microbial biomass carbon (MBC) and nitrogen (MBN), metabolic quotient (qCO2), fluorescein diacetate (FDA), dehydrogenase (DHA), β-glucosidase, and urease. Microbial biomass, metabolic quotient and enzyme activities were evaluated due their prevalent usage in evaluation of soil quality and use in soil quality indices. Overall, microbial biomass and all of the enzyme activities were greater under no-till compared to tillage. One exception to this was that under chisel tillage, there was no difference in MBC between the tilled plots and no-till. The qCO2 was greater under tillage than under no-till indicating more active microbes in tilled soil, perhaps compensating for the reduced quantity. In contrast, when looking at only long-term experiments, qCO2 was similar under both tillage and no-till, which may indicate that eventually microbes in no-till plots become as active as those in tilled plots even with the larger microbial community. The findings of this study illustrate that no-till and even reduced tillage, such as chisel tillage, promote larger microbial communities and greater enzymatic activity.
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Low number of fixed somatic mutations in a long-lived oak tree

Low number of fixed somatic mutations in a long-lived oak tree | plant cell genetics | Scoop.it

Because plants do not possess a defined germline, deleterious somatic mutations can be passed to gametes, and a large number of cell divisions separating zygote from gamete formation may lead to many mutations in long-lived plants. We sequenced the genome of two terminal branches of a 234-year-old oak tree and found several fixed somatic single-nucleotide variants whose sequential appearance in the tree could be traced along nested sectors of younger branches. Our data suggest that stem cells of shoot meristems in trees are robustly protected from the accumulation of mutations.

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Stable Production of the Antimalarial Drug Artemisinin in the Moss Physcomitrella patens

Stable Production of the Antimalarial Drug Artemisinin in the Moss Physcomitrella patens | plant cell genetics | Scoop.it

Malaria is a real and constant danger to nearly half of the world’s population of 7.4 billion people. In 2015, 212 million cases were reported along with 429,000 estimated deaths. The World Health Organization recommends artemisinin-based combinatorial therapies, and the artemisinin for this purpose is mainly isolated from the plant Artemisia annua. However, the plant supply of artemisinin is irregular, leading to fluctuation in prices. Here, we report the development of a simple, sustainable, and scalable production platform of artemisinin. The five genes involved in artemisinin biosynthesis were engineered into the moss Physcomitrella patens via direct in vivo assembly of multiple DNA fragments. In vivo biosynthesis of artemisinin was obtained without further modifications. A high initial production of 0.21 mg/g dry weight artemisinin was observed after only 3 days of cultivation. Our study shows that P. patens can be a sustainable and efficient production platform of artemisinin that without further modifications allow for industrial-scale production. A stable supply of artemisinin will lower the price of artemisinin-based treatments, hence become more affordable to the lower income communities most affected by malaria; an important step toward containment of this deadly disease threatening millions every year.

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Frontiers | Testing of Auxotrophic Selection Markers for Use in the Moss Physcomitrella Provides New Insights into the Mechanisms of Targeted Recombination | Plant Science

Frontiers | Testing of Auxotrophic Selection Markers for Use in the Moss Physcomitrella Provides New Insights into the Mechanisms of Targeted Recombination | Plant Science | plant cell genetics | Scoop.it
The moss Physcomitrella patens is unique among plants in that homologous recombination can be used to knock out genes, just like in yeast. Furthermore, transformed plasmids can be rescued from Physcomitrella back into E. coli, similar to yeast. In the present study, we have tested if a third important tool from yeast molecular genetics, auxotrophic selection markers, can be used in Physcomitrella. Two auxotrophic moss strains were made by knocking out the PpHIS3 geThe moss Physcomitrella patens is unique among plants in that homologous recombination can be used to knock out genes, just like in yeast. Furthermore, transformed plasmids can be rescued from Physcomitrella back into E. coli, similar to yeast. In the present study, we have tested if a third important tool from yeast molecular genetics, auxotrophic selection markers, can be used in Physcomitrella. Two auxotrophic moss strains were made by knocking out the PpHIS3 gene encoding imidazoleglycerol-phosphate dehydratase, and the PpTRP1 gene encoding phosphoribosylanthranilate isomerase, disrupting the biosynthesis of histidine and tryptophan, respectively. The resulting PpHIS3∆ and PpTRP1∆ knockout strains were unable to grow on medium lacking histidine or tryptophan. The PpHIS3∆ strain was used to test selection of transformants by complementation of an auxotrophic marker. We found that the PpHIS3∆ strain could be complemented by transformation with a plasmid expressing the PpHIS3 gene from the CaMV 35S promoter, allowing the strain to grow on medium lacking histidine. Both linearized plasmids and circular supercoiled plasmids could complement the auxotrophic marker, and plasmids from both types of transformants could be rescued back into E. coli. Plasmids rescued from circular transformants were identical to the original plasmid, whereas plasmids rescued from linearized transformants had deletions generated by recombination between micro-homologies in the plasmids. Our results show that cloning by complementation of an auxotrophic marker works in Physcomitrella, which opens the door for using auxotrophic selection markers in moss molecular genetics. This will facilitate the adaptation of shuttle plasmid dependent methods from yeast molecular genetics for use in Physcomitrella.
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Sweet transgenic immunity

Sweet transgenic immunity | plant cell genetics | Scoop.it
Banana is not just every kid’s favourite fruit; it is also a major staple crop that feeds (directly or indirectly) half a billion people in (sub)tropical areas. Unfortunately, banana is once again threatened by Fusarium wilt, a devastating fungal disease. A mostly Australian team has now used biotechnology to create a transgenic resistant banana. Credit: David Hancock/Alamy Stock Photo Last century, the Gros Michel cultivar was decimated by the same disease, and replaced by the resistant Cavendish — the fruit most of us are familiar with. But Cavendish is no match for a new Fusarium race now spreading in Asia and Africa, causing fears over what may happen when the disease reaches Latin America, the most important region of production. No chemical treatment is efficient, and spores can stay dormant in the soil for decades. As in the case of the Hawaiian papaya, saved from the ringspot virus by a transgenic approach, the authors thought to use biotechnology to increase banana resistance to the disease. The researchers overexpressed two genes, including one nucleotide-binding/leucine-rich repeat (NB-LRR) gene called RGA2 from a resistant wild banana. Unlike previous research performed in a glasshouse, the transformed lines were tested in a heavily contaminated field. The results after three years were impressive: while most of the control plants were dead or infected, the plants highly expressing RGA2 were completely immune to the disease, without any detrimental effect on yield. Even more interesting from a regulatory and public acceptance point of view, the cultivated banana already contains a weakly expressed RGA2 homologue; therefore slightly modifying the endogenous gene may lead to the same level of resistance. This success story in the making is another reminder of the power of crop biotechnology as a tool to improve food security.

Via Christophe Jacquet
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Impact of genetically engineered maize on agronomic, environmental and toxicological traits: a meta-analysis of 21 years of field data

Impact of genetically engineered maize on agronomic, environmental and toxicological traits: a meta-analysis of 21 years of field data | plant cell genetics | Scoop.it

Despite the extensive cultivation of genetically engineered (GE) maize and considerable number of scientific reports on its agro-environmental impact, the risks and benefits of GE maize are still being debated and concerns about safety remain. This meta-analysis aimed at increasing knowledge on agronomic, environmental and toxicological traits of GE maize by analyzing the peer-reviewed literature (from 1996 to 2016) on yield, grain quality, non-target organisms (NTOs), target organisms (TOs) and soil biomass decomposition. Results provided strong evidence that GE maize performed better than its near isogenic line: grain yield was 5.6 to 24.5% higher with lower concentrations of mycotoxins (−28.8%), fumonisin (−30.6%) and thricotecens (−36.5%). The NTOs analyzed were not affected by GE maize, except for Braconidae, represented by a parasitoid of European corn borer, the target of Lepidoptera active Bt maize. Biogeochemical cycle parameters such as lignin content in stalks and leaves did not vary, whereas biomass decomposition was higher in GE maize. The results support the cultivation of GE maize, mainly due to enhanced grain quality and reduction of human exposure to mycotoxins. Furthermore, the reduction of the parasitoid of the target and the lack of consistent effects on other NTOs are confirmed.

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Transcriptome dynamics at Arabidopsis graft junctions reveal an intertissue recognition mechanism that activates vascular regeneration

Transcriptome dynamics at Arabidopsis graft junctions reveal an intertissue recognition mechanism that activates vascular regeneration | plant cell genetics | Scoop.it
Plant grafting is an ancient and agriculturally important technique. Despite its widespread use, little is known about how plants graft. Here, we perform a genome-wide transcriptome analysis of tissues above and below graft junctions. We observed a sequential activation of genes important for vascular development including cambium-, phloem-, and xylem-related genes. Massive changes in gene expression that rapidly differentiate the top of the graft from the bottom occur. These changes disappear as the graft heals and the vasculature reconnects. Many genes below the junction rapidly respond to the presence of attached tissues including genes involved in vascular differentiation and cell division. This intertissue communication process occurs independently of functional vascular connections and acts as a signal to activate vascular regeneration.

The ability for cut tissues to join and form a chimeric organism is a remarkable property of many plants; however, grafting is poorly characterized at the molecular level. To better understand this process, we monitored genome-wide gene expression changes in grafted Arabidopsis thaliana hypocotyls. We observed a sequential activation of genes associated with cambium, phloem, and xylem formation. Tissues above and below the graft rapidly developed an asymmetry such that many genes were more highly expressed on one side than on the other. This asymmetry correlated with sugar-responsive genes, and we observed an accumulation of starch above the graft junction. This accumulation decreased along with asymmetry once the sugar-transporting vascular tissues reconnected. Despite the initial starvation response below the graft, many genes associated with vascular formation were rapidly activated in grafted tissues but not in cut and separated tissues, indicating that a recognition mechanism was activated independently of functional vascular connections. Auxin, which is transported cell to cell, had a rapidly elevated response that was symmetric, suggesting that auxin was perceived by the root within hours of tissue attachment to activate the vascular regeneration process. A subset of genes was expressed only in grafted tissues, indicating that wound healing proceeded via different mechanisms depending on the presence or absence of adjoining tissues. Such a recognition process could have broader relevance for tissue regeneration, intertissue communication, and tissue fusion events.
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Meeting report: Separate product from process: framing the debate that surrounds the potential uptake of new breeding technologies

Meeting report: Separate product from process: framing the debate that surrounds the potential uptake of new breeding technologies | plant cell genetics | Scoop.it

The use of the CRISPR-Cas9 system for precision genome editing (GE) has been regularly described as a ‘game-changing technology’ that allows a more precise targeting of DNA to induce specific nucleotide variations (Belhaj et al. 2015); however, the use of GE in plants for the production of food or feed still faces an uncertain regulatory future. This follows on from a long-standing public distrust of genetically modified organisms (GMOs), an opinion predicated from, amongst other things, controversial yet discredited scientific studies and public miscommunications. Public unease with this technology has guided government policy on the permitted uses of the products of GMOs, such that growth of these crops is now restricted throughout most of the European Union (EU). The plant science community stands at an important crossroads at which the future uses of plants generated by GE technologies will be decided..

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The push and pull of plant specialized metabolism underlies a long‐standing, colorful mystery

The push and pull of plant specialized metabolism underlies a long‐standing, colorful mystery | plant cell genetics | Scoop.it


This article is a Commentary on Lopez‐Nieves et al., 217: 896–908.

Three types of compounds – chlorophylls, carotenoids and anthocyanins – are responsible for generating the vast majority of colors in the plant world. However, in 1918, a PhD student working with Richard Willstätter – the 1915 Chemistry Nobel Prize Winner who studied chlorophyll – recognized that the red color in beets is different (Ainley & Robinson, 1937). The red, purple and blue colors in many plants are a result of accumulation of anthocyanins, which lack nitrogen. However, the red pigment in beets – composed of the compound betanin – was found to contain nitrogen. Betanin soon came to be annotated (Ainley & Robinson, 1937) – with some suspicion (Pucher et al., 1938) – as a ‘nitrogenous anthocyanin’, with one or more amino acids conjugated to an anthocyanin backbone. However, this inference was proved incorrect when, in 1957, it was demonstrated that the nitrogen in betanin was actually contained in a pyrrole ring and not in a conjugated amino acid (Peterson & Joslyn, 1958). This intriguing difference between

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Speed breeding is a powerful tool to accelerate crop research and breeding

Speed breeding is a powerful tool to accelerate crop research and breeding | plant cell genetics | Scoop.it

The growing human population and a changing environment have raised significant concern for global food security, with the current improvement rate of several important crops inadequate to meet future demand1. This slow improvement rate is attributed partly to the long generation times of crop plants. Here, we present a method called ‘speed breeding’, which greatly shortens generation time and accelerates breeding and research programmes. Speed breeding can be used to achieve up to 6 generations per year for spring wheat (Triticum aestivum), durum wheat (T. durum), barley (Hordeum vulgare), chickpea (Cicer arietinum) and pea (Pisum sativum), and 4 generations for canola (Brassica napus), instead of 2–3 under normal glasshouse conditions. We demonstrate that speed breeding in fully enclosed, controlled-environment growth chambers can accelerate plant development for research purposes, including phenotyping of adult plant traits, mutant studies and transformation. The use of supplemental lighting in a glasshouse environment allows rapid generation cycling through single seed descent (SSD) and potential for adaptation to larger-scale crop improvement programs. Cost saving through light-emitting diode (LED) supplemental lighting is also outlined. We envisage great potential for integrating speed breeding with other modern crop breeding technologies, including high-throughput genotyping, genome editing and genomic selection, accelerating the rate of crop improvement.

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Physcomitrella MADS-box genes regulate water supply and sperm movement for fertilization

Physcomitrella MADS-box genes regulate water supply and sperm movement for fertilization | plant cell genetics | Scoop.it

MIKC classic (MIKCC)-type MADS-box genes encode transcription factors that function in various developmental processes, including angiosperm floral organ identity. Phylogenetic analyses of the MIKCC-type MADS-box family, including genes from non-flowering plants, suggest that the increased numbers of these genes in flowering plants is related to their functional divergence; however, their precise functions in non-flowering plants and their evolution throughout land plant diversification are unknown. Here, we show that MIKCC-type MADS-box genes in the moss Physcomitrella patens function in two ways to enable fertilization. Analyses of protein localization, deletion mutants and overexpression lines of all six genes indicate that three MIKCC-type MADS-box genes redundantly regulate cell division and growth in the stems for appropriate external water conduction, as well as the formation of sperm with motile flagella. The former function appears to be maintained in the flowering plant lineage, while the latter was lost in accordance with the loss of sperm.

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Bioproduction of a betalain color palette in Saccharomyces cerevisiae

Bioproduction of a betalain color palette in Saccharomyces cerevisiae | plant cell genetics | Scoop.it
Betalains are a family of natural pigments found exclusively in the plant order Caryophyllales. All members of this chemical family are biosynthesized through the common intermediate betalamic acid, which is capable of spontaneously condensing with various primary and secondary amines to produce betalains. Of particular interest is the red-violet betanin, most commonly obtained from Beta vulgaris (beet) as a natural food dye. We demonstrate the first complete microbial production of betanin in Saccharomyces cerevisiae from glucose, an early step towards a fermentation process enabling rapid, on-demand production of this natural dye. A titer of 17 mg/L was achieved, corresponding to a color intensity obtained from 10 g/L of beetroot extract. Further, we expanded the spectrum of betalain colors by condensing betalamic acid with various amines fed to an engineered strain of S. cerevisiae. Our work establishes a platform for microbial production of betalains of various colors as a potential alternative to land- and resource-intensive agricultural production.
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The P. patens chromosome‐scale assembly reveals moss genome structure and evolution

The P. patens chromosome‐scale assembly reveals moss genome structure and evolution | plant cell genetics | Scoop.it

The draft genome of the moss model, Physcomitrella patens, comprised approximately 2,000 unordered scaffolds. In order to enable analyses of genome structure and evolution we generated a chromosome-scale genome assembly using genetic linkage as well as (end) sequencing of long DNA fragments. We find that 57% of the genome comprises transposable elements (TEs), some of which may be actively transposing during the life cycle. Unlike in flowering plant genomes, gene- and TE-rich regions show an overall even distribution along the chromosomes. However, the chromosomes are mono-centric with peaks of a class of Copia elements potentially coinciding with centromeres. Gene body methylation is evident in 5.7% of the protein-coding genes, typically coinciding with low GC and low expression. Some giant virus insertions are transcriptionally active and might protect gametes from viral infection via siRNA mediated silencing. Structure-based detection methods show that the genome evolved via two rounds of whole genome duplications (WGDs), apparently common in mosses but not in liverworts and hornworts. Several hundred genes are present in colinear regions conserved since the last common ancestor of plants. These syntenic regions are enriched for functions related to plant-specific cell growth and tissue organization. The P. patens genome lacks the TE-rich pericentromeric and gene-rich distal regions typical for most flowering plant genomes. More non-seed plant genomes are needed to unravel how plant genomes evolve, and to understand whether the P. patens genome structure is typical for mosses or bryophytes.

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Identification of a Novel Maize Protein Important for Paramutation at the purple plant1 Locus

Identification of a Novel Maize Protein Important for Paramutation at the purple plant1 Locus | plant cell genetics | Scoop.it
Paramutation occurs at a specific locus when one epiallele, referred to as paramutagenic, facilitates a heritable change in the regulation of the other epiallele, which is referred to as paramutable (reviewed in Arteaga-Vazquez and Chandler, 2010). Because these two states have the same DNA sequence but differ epigenetically, they are referred to as epialleles, or states, rather than alleles. Generally, transcription from paramutable epialleles is heritably repressed following exposure to paramutagenic alleles. Paramutation was first discovered in the 1950s as an epigenetic phenomenon affecting maize (Zea mays) anthocyanin production regulated by red1 (r1) and booster1 (b1). For example, the paramutable B-I epiallele produces strong anthocyanin expression, but when crossed to the low-anthocyanin paramutagenic B′ epiallele, the B-I allele is converted in trans into a heritable, low-anthocyanin, paramutagenic B′ epiallele. Paramutation seems to involve sequences affecting transcription, such as an 853-bp tandem repeat 100 kb upstream of B-I, which acts as a transcriptional enhancer.
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How to get old without aging

How to get old without aging | plant cell genetics | Scoop.it

The low number of mutations in multiple sectors from a 234-year-old oak tree reveals possible mechanisms to avoid the irreversible build-up of mutations in long-lived plants. How do trees manage to survive for hundreds or even thousands of years1,2? How do they avoid the gradual accumulation of mutations due to DNA replication errors and environmental influences such as ultraviolet radiation? In this issue of Nature Plants, Schmid-Siegert et al.3 address this long-standing question by studying genetic diversity in a tree on their campus. The tree is locally known as Napoleon’s Oak and commemorates the visit of the victorious general in the year 1800. Napoleon has been dead now for almost two centuries and so are all his contemporaries, but the oak that bears his name has grown into a magnificent tree. Why do trees live so much longer than us humans? The authors decided to count the number of mutations in Napoleon’s Oak through a great citizens’ outreach project (http://www.napoleome.ch).

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A Review of Biotechnological Artemisinin Production in Plants

A Review of Biotechnological Artemisinin Production in Plants | plant cell genetics | Scoop.it

Malaria is still an eminent threat to major parts of the world population mainly in sub-Saharan Africa. Researchers around the world continuously seek novel solutions to either eliminate or treat the disease. Artemisinin, isolated from the Chinese medicinal herb Artemisia annua, is the active ingredient in artemisinin-based combination therapies used to treat the disease. However, naturally artemisinin is produced in small quantities, which leads to a shortage of global supply. Due to its complex structure, it is difficult chemically synthesize. Thus to date, A. annua remains as the main commercial source of artemisinin. Current advances in genetic and metabolic engineering drives to more diverse approaches and developments on improving in planta production of artemisinin, both in A. annua and in other plants. In this review, we describe efforts in bioengineering to obtain a higher production of artemisinin in A. annua and stable heterologous in planta systems. The current progress and advancements provides hope for significantly improved production in plants.

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