Betalains are water-soluble nitrogen-containing pigments which are subdivided in red-violet betacyanins and yellow-orange betaxanthins. Due to glycosylation and acylation betalains exhibit a huge structural diversity. Betanin (betanidin-5-O-β-glucoside) is the most common betacyanin in the plant kingdom. According to the regulation on food additives betanin is permitted quantum satis as a natural red food colorant (E162). Moreover, betanin is used as colorant in cosmetics and pharmaceuticals.
Recently, potential health benefits of betalains and betalain-rich foods (e.g., red beet, Opuntia sp.) have been discussed. Betanin is a scavenger of reactive oxygen species and exhibits gene-regulatory activity partly via Nrf2-dependent signaling pathways. Betanin may induce phase II enzymes and antioxidant defense mechanisms. Furthermore, betanin possibly prevents LDL oxidation and DNA damage. Potential blood pressure lowering effects of red beet seem to be mainly mediated by dietary nitrate rather than by betanin per se.
Orientation of cell division is critical for plant morphogenesis. This is evident in the formation and function of meristems and for morphogenetic transitions. Mosses undergo such transitions: from two-dimensional tip-growing filaments (protonema) to the generation of three-dimensional leaf-like structures (gametophores).The Defective Kernel 1 (DEK1) protein plays a key role in the perception of and/or response to positional cues that specify the formation and function of the epidermal layer in developing seeds of flowering plants. The moss Physcomitrella patens contains the highly conserved DEK1 gene.Using efficient gene targeting, we generated a precise PpDEK1 deletion (∆dek1), which resulted in normal filamentous growth of protonema. Two distinct mutant phenotypes were observed: an excess of buds on the protonema, and abnormal cell divisions in the emerging buds resulting in developmental arrest and the absence of three-dimensional growth. Overexpression of a complete PpDEK1 cDNA, or the calpain domain of PpDEK1 alone, successfully complements both phenotypes.These results in P. patens demonstrate the morphogenetic importance of the DEK1 protein in the control of oriented cell divisions. As it is not for protonema, it will allow dissection of the structure/function relationships of the different domains of DEK1 using gene targeting in null mutant background.
The variegated flower colors of many plant species have been shown to result from the insertion or excision of transposable elements into genes that encode enzymes involved in anthocyanin synthesis. To date, however, it has not been established whether this phenomenon is responsible for the variegation produced by other pigments such as betalains. During betalain synthesis in red beet, the enzyme CYP76AD1 catalyzes the conversion of l-dihydroxyphenylalanine (DOPA) to cyclo-DOPA. RNA sequencing (RNA-seq) analysis indicated that the homologous gene in four o’clock (Mirabilis jalapa) is CYP76AD3. Here, we show that in four o’clock with red perianths, the CYP76AD3 gene consists of one intron and two exons; however, in a mutant with a perianth showing red variegation on a yellow background, a transposable element, dTmj1, had been excised from the intron. This is the first report that a transposition event affecting a gene encoding an enzyme for betalain synthesis can result in a variegated flower phenotype.
Can we use transgenic plants to limit aphid negative impact on plants? And if yes, which efficient technical means can we develop? Guo et al in the lab of Rongxiang Fang in Beijing, propose to generate in planta, small ...
TALEN-induced mutation of all homologous copies of a gene that represses resistance to an important wheat pathogen confers a trait that has eluded plant breeders for decades.
Sequence-specific nucleases have been applied to engineer targeted modifications in polyploid genomes1, but simultaneous modification of multiple homoeoalleles has not been reported. Here we use transcription activator–like effector nuclease (TALEN)2, 3 and clustered, regularly interspaced, short palindromic repeats (CRISPR)-Cas9 (refs. 4,5) technologies in hexaploid bread wheat to introduce targeted mutations in the three homoeoalleles that encode MILDEW-RESISTANCE LOCUS (MLO) proteins6. Genetic redundancy has prevented evaluation of whether mutation of all three MLO alleles in bread wheat might confer resistance to powdery mildew, a trait not found in natural populations7. We show that TALEN-induced mutation of all three TaMLO homoeologs in the same plant confers heritable broad-spectrum resistance to powdery mildew. We further use CRISPR-Cas9 technology to generate transgenic wheat plants that carry mutations in the TaMLO-A1 allele. We also demonstrate the feasibility of engineering targeted DNA insertion in bread wheat through nonhomologous end joining of the double-strand breaks caused by TALENs. Our findings provide a methodological framework to improve polyploid crops.
Bread wheat (hexaploid Triticum aestivum) provides an extraordinary 10,000-y story of a new species, established by early farmers, selecting for simple agronomical traits to facilitate efficient and plentiful grain harvest. The genetic changes underlying wheat domestication over thousands of years, however, included not just a collection of beneficial single gene mutations, but also introgressions and whole genome duplication. The hexaploidization event occurred spontaneously in nature, but the resulting wild species did not survive; it is known only in its domesticated form. Evolutionary bottleneck(s) reduced genetic variation of the species, and it was introduced broadly outside its native geographical range and habitat. Nevertheless, modern breeding programs delivered high-yield elite cultivars, which are planted in most major wheat-producing areas of the world. In the face of quickly declining arable land expansion and challenges from climate change, the following question arises: where can we find the next wave of increase in yield and global production of wheat? In PNAS, Kempe et al. (1) describe molecular engineering of an elegant male sterility–fertility restoration system for the exploration of heterosis (hybrid plant vigor) in wheat. In the future, this system could facilitate introduction of hybrid seeds on a large scale.
Emmer wheat, one of the eight founder crops domesticated in the Middle East about 10,000 y ago, was instrumental in spawning the Agricultural Revolution. The transition of wild to cultivated emmer initiated the extensive genetic restructuring of domesticated wheat, primarily involving mutations that resulted in the transition of types with natural seed dispersal mechanisms (brittle spikes) to types with a nonbrittle rachis (2). The initial transition from the wild habitat to cultivated fields also involved selection for free-threshing seeds, nondormant seeds, uniform and rapid germination, erect plants, and increased grain size. It was a domesticated derivative of emmer that hybridized with goatgrass about 8,000 y ago (3), probably southeast of the Caspian Sea, that resulted in the first hexaploid bread wheat (4).
In vascular plants, strigolactones (SLs) are known for their hormonal role and for their role as signal molecules in the rhizosphere. SLs are also produced by the moss Physcomitrella patens, in which they act as signaling factors for controlling filament extension and possibly interaction with neighboring individuals. To gain a better understanding of SL action at the cellular level, we investigated the effect of exogenously added molecules (SLs or analogs) in moss growth media. We used the previously characterized Ppccd8 mutant that is deficient in SL synthesis and showed that SLs affect moss protonema extension by reducing caulonema cell elongation and mainly cell division rate, both in light and dark conditions. Based on this effect, we set up bioassays to examine chemical structure requirements for SL activity in moss. The results suggest that compounds GR24, GR5, and 5-deoxystrigol are active in moss (as in pea), while other analogs that are highly active in the control of pea branching show little activity in moss. Interestingly, the karrikinolide KAR1, which shares molecular features with SLs, did not have any effect on filament growth, even though the moss genome contains several genes homologous to KAI2 (encoding the KAR1 receptor) and no canonical homologue to D14 (encoding the SL receptor). Further studies should investigate whether SL signaling pathways have been conserved during land plant evolution.
Once again, there are calls to reopen the debate on genetically modified (GM) crops. I find these calls frustrating and unnecessarily decisive. In my opinion the GM debate, on both sides, continues to hamper the urgent need to address the diverse and pressing challenges of global food security and environmental sustainability. The destructive power of the debate comes from its conflation of unrelated issues, coupled with deeply rooted misconceptions of the nature of agriculture.
An analysis of key genes and enzymes of the betacyanin biosynthetic pathway in Amaranthus hypochondriacus (Ah) was performed. Complete cDNA sequence of Ah genes coding for cyclo-DOPA 5-O glucosyltransferase (AhcDOPA5-GT), two 4, 5-DOPA-extradiol-dioxygenase isoforms (AhDODA-1 and AhDODA-2, respectively), and a betanidin 5-O-glucosyltransferase (AhB5-GT), plus the partial sequence of an orthologue of the cytochrome P-450 R gene (CYP76AD1) were obtained. With the exception AhDODA-2, which had a closer phylogenetic relationship to DODA-like genes in anthocyanin-synthesizing plants, all genes analyzed closely resembled those reported in related Caryophyllales species. The measurement of basal gene expression levels, in addition to the DOPA oxidase tyrosinase (DOT) activity, in different tissues of three Ah genotypes having contrasting pigmentation levels (green to red-purple) was determined. Additional analyses were performed in Ah plants subjected to salt and drought stress and to two different insect herbivory regimes. Basal pigmentation accumulation in leaves, stems and roots of betacyanic plants correlated with higher expression levels of AhDODA-1 and AhB5-GT, whereas DOT activity levels coincided with pigment accumulation in stems and roots and with the acyanic nature of green plants, respectively, but not with pigmentation in leaves. Although the abiotic stress treatments tested produced changes in pigment levels in different tissues, pigment accumulation was the highest in leaves and stems of drought stressed betacyanic plants, respectively. However, tissue pigment accumulation in stressed Ah plants did not always correlate with betacyanin biosynthetic gene expression levels and/or DOT activity. This effect was tissue- and genotype-dependent, and further suggested that other unexamined factors were influencing pigment content in stressed Ah. The results obtained from the insect herbivory assays, particularly in acyanic plants, also support the proposal that these genes could have functions other than betacyanin biosynthesis.
no double blindThis article describes the nutrient and elemental composition, including residues of herbicides and pesticides, of 31 soybean batches from Iowa, USA. The soy samples were grouped into three different categories: (i) genetically modified, glyphosate-tolerant soy (GM-soy); (ii) unmodified soy cultivated using a conventional “chemical” cultivation regime; and (iii) unmodified soy cultivated using an organic cultivation regime. Organic soybeans showed the healthiest nutritional profile with more sugars, such as glucose, fructose, sucrose and maltose, significantly more total protein, zinc and less fibre than both conventional and GM-soy. Organic soybeans also contained less total saturated fat and total omega-6 fatty acids than both conventional and GM-soy. GM-soy contained high residues of glyphosate and AMPA (mean 3.3 and 5.7 mg/kg, respectively). Conventional and organic soybean batches contained none of these agrochemicals. Using 35 different nutritional and elemental variables to characterise each soy sample, we were able to discriminate GM, conventional and organic soybeans without exception, demonstrating “substantial non-equivalence” in compositional characteristics for ‘ready-to-market’ soybeans.
Jean-Pierre Zryd's insight:
To be read "cum grano salis"; it's not a double blind study; statistics are at the limit of significance level and finally some authors have huge conflicts of interest
With the advent of deep sequencing technologies and the ability to analyze whole genome sequences and transcriptomes, there has been a growing interest in exploring putative functions of the very large fraction of the genome that is commonly referred to as “junk DNA.” Whereas this is an issue of considerable importance in genome biology, there is an unfortunate tendency for researchers and science writers to proclaim the demise of junk DNA on a regular basis without properly addressing some of the fundamental issues that first led to the rise of the concept. In this review, we provide an overview of the major arguments that have been presented in support of the notion that a large portion of most eukaryotic genomes lacks an organism-level function. Some of these are based on observations or basic genetic principles that are decades old, whereas others stem from new knowledge regarding molecular processes such as transcription and gene regulation.
Over 70 years ago, increased spontaneous mutation rates were observed in Drosophila spp. hybrids, but the genetic basis of this phenomenon is not well understood. The model plant Arabidopsis (Arabidopsis thaliana) offers unique opportunities to study the types of mutations induced upon hybridization and the frequency of their occurrence. Understanding the mutational effects of hybridization is important, as many crop plants are grown as hybrids. Besides, hybridization is important for speciation and its effects on genome integrity could be critical, as chromosomal rearrangements can lead to reproductive isolation. We examined the rates of hybridization-induced point and frameshift mutations as well as homologous recombination events in intraspecific Arabidopsis hybrids using a set of transgenic mutation detector lines that carry mutated or truncated versions of a reporter gene. We found that hybridization alters the frequency of different kinds of mutations. In general, Columbia (Col) × Cape Verde Islands and Col × C24 hybrid progeny had decreased T→G and T→A transversion rates but an increased C→T transition rate. Significant changes in frameshift mutation rates were also observed in some hybrids. In Col × C24 hybrids, there is a trend for increased homologous recombination rates, except for the hybrids from one line, while in Col × Cape Verde Islands hybrids, this rate is decreased. The overall genetic distance of the parents had no influence on mutation rates in the progeny, as closely related accessions on occasion displayed higher mutation rates than accessions that are separated farther apart. However, reciprocal hybrids had significantly different mutation rates, suggesting parent-of-origin-dependent effects on the mutation frequency.
The use of plant (cell) suspension cultures in phototrophic mode on an industrially relevant scale is limited to two systems worldwide. These are the moss-based BryoTechnology™ and the duckweed-based SYNLEX™ production systems being developed by greenovation biotech GmbH and Synthon, respectively. Both production platforms make use of intact plants, rather than isolated cells, which are grown in simple salt media to manufacture recombinant, high value pharmaceutical proteins. They exploit unique features of plants like homogenous N-glycosylation, absolute genetic stability, and pathogen safety to create biopharmaceuticals of outstanding quality. On the equipment side, both processes build on single use, disposable solutions bringing about high flexibility and regulatory safety. Despite sharing all of the above-mentioned aspects, these two systems differ remarkably in several details. Physcomitrella patens, the moss behind BryoTechnology™, is unique in its potential for genetic engineering. Resembling yeast systems in that aspect, it allows for rapid generation of product-tailored production platforms. The SYNLEX™-system on the other hand, with Lemna minor as producing organism has a very basic process setup with few controls and good scale-up potential. This chapter discusses strengths and weaknesses of both systems side-by-side, describes their current technological development status, and gives a short future outlook.
DEK1 of higher plants plays an essential role in position dependent signaling and consists of a large transmembrane domain (MEM) linked to a protease catalytic domain (CysPc) and a regulatory domain (C2L). Here we show that the postulated sensory Loop of the MEM domain plays an important role in the developmental regulation of DEK1 activity in the moss Physcomitrella patens. Compared with P. patens lacking DEK1 (∆dek1), the dek1∆loop mutant correctly positions the division plane in the bud apical cell. In contrast to an early developmental arrest of ∆dek1 buds, dek1∆loop develops aberrant gametophores lacking expanded phyllids resulting from mis-regulation of mitotic activity. In contrast to the highly conserved sequence of the catalytic CysPc domain, the Loop is highly variable in land plants. Functionally, the sequence from Marchantia polymorpha fully complements the dek1∆loop phenotype, whereas sequences from Zea mays and Arabidopsis thaliana give phenotypes with retarded growth and affected phyllid development. New bioinformatic analysis identifies MEM as a member of the Major Facilitator Superfamily, membrane transporters reacting to stimuli from the external environment. Transcriptome analysis comparing WT and ∆dek1 tissues identifies an effect of two groups of transcripts connected to dek1 mutant phenotypes, i.e. transcripts related to cell wall remodeling and regulation of the APB2 and APB3 transcription factors known to regulate bud initiation. Finally, new sequence data support the hypothesis that the advanced charophyte algae that evolved into ancestral land plants lost cytosolic calpains, retaining DEK1 as the sole calpain in the evolving land plant lineage.
Red beet is a rich source of betalain pigments, which can protect against age-related diseases. Betalain pigment can be used as a natural additive for food, cosmetics and drugs in the form of beet juice as well as beet powder. Processing stability in food is the most important issue nowadays. Microencapsulation of pigments creates stable powders. The aim of this study was to investigate the effect of carrier type on stability of beetroot pigments. Raw material used in the study was 100% beetroot juice. Low-crystallised maltodextrin, Arabic gum and a mixture of both (1:1) were used as carriers. Drying was carried out in a spray-drier at a disc speed of 39,000 rpm and a solution flux rate of 0.3 and 0.8 × 10− 6 m3 s− 1. The inlet air temperature was 160 °C. In powders physical properties such as hygroscopicity, dry matter solubility and size, which can influence future application, were tested. The highest violet pigment content was observed in powders based on Arabic gum, but the content of yellow pigment was low. Reverse results were seen for microparticles with maltodextrin. Moreover, for a longer period of time microcapsules of Arabic gum and beetroot pigments were stable, because of their lower hygroscopicity in comparison to maltodextrin. Nevertheless, the authors recommend beetroot pigments obtained with maltodextrin as natural food pigments for food supplements.
nRecent discoveries have highlighted the dramatic evolutionary transformation of massive, ground-dwelling theropod dinosaurs into light, volant birds. Here, we apply Bayesian approaches (originally developed for inferring geographic spread and rates of molecular evolution in viruses) in a different context: to infer size changes and rates of anatomical innovation (across up to 1549 skeletal characters) in fossils. These approaches identify two drivers underlying the dinosaur-bird transition. The theropod lineage directly ancestral to birds undergoes sustained miniaturization across 50 million years and at least 12 consecutive branches (internodes) and evolves skeletal adaptations four times faster than other dinosaurs. The distinct, prolonged phase of miniaturization along the bird stem would have facilitated the evolution of many novelties associated with small body size, such as reorientation of body mass, increased aerial ability, and paedomorphic skulls with reduced snouts but enlarged eyes and brains.
International Business Times UK Chinese Researchers Create Disease-Resistant Wheat by Deleting Genes Mashable The gene-deletion trick is particularly tough to do in wheat because the plant has three genomes — with largely similar copies of the same...
Allopolyploidization, the combination of the genomes from two different species, has been a major source of evolutionary innovation and a driver of speciation and environmental adaptation. In plants, it has also contributed greatly to crop domestication, as the superior properties of many modern crop plants were conferred by ancient allopolyploidization events. It is generally thought that allopolyploidization occurred through hybridization events between species, accompanied or followed by genome duplication. Although many allopolyploids arose from closely related species (congeners), there are also allopolyploid species that were formed from more distantly related progenitor species belonging to different genera or even different tribes. Here we have examined the possibility that allopolyploidization can also occur by asexual mechanisms. We show that upon grafting[mdash]a mechanism of plant-plant interaction that is widespread in nature[mdash]entire nuclear genomes can be transferred between plant cells. We provide direct evidence for this process resulting in speciation by creating a new allopolyploid plant species from a herbaceous species and a woody species in the nightshade family. The new species is fertile and produces fertile progeny. Our data highlight natural grafting as a potential asexual mechanism of speciation and also provide a method for the generation of novel allopolyploid crop species.
Over the last 300 years, plant science research has provided important knowledge and technologies for advancing the sustainability of agriculture. In this Essay, I describe how basic research advances have been translated into crop improvement, explore some lessons learned, and discuss the potential for current and future contribution of plant genetic improvement technologies to continue to enhance food security and agricultural sustainability.
Multiple geranylgeranyl diphosphate synthases (GGPPS) for biosynthesis of geranylgeranyl diphosphate (GGPP) exist in plants. GGPP is produced in the isoprenoid pathway and is a central precursor for various primary and specialized plant metabolites. Therefore, its biosynthesis is an essential regulatory point in the isoprenoid pathway. We selected 119 GGPPSs from 48 species representing all major plant lineages, based on stringent homology criteria. After the diversification of land plants, the number of GGPPS paralogs per species increases. Already in the moss Physcomitrella patens, GGPPS appears to be encoded by multiple paralogous genes. In gymnosperms, neofunctionalization of GGPPS may have enabled optimized biosynthesis of primary and specialized metabolites. Notably, lineage-specific expansion of GGPPS occurred in land plants. As a representative species we focused here on Arabidopsis thaliana, which retained the highest number of GGPPS paralogs (twelve) among the 48 species we considered in this study. Our results show that the A. thaliana GGPPS gene family is an example of evolution involving neo- and subfunctionalization as well as pseudogenization. We propose subfunctionalization as one of the main mechanisms allowing the maintenance of multiple GGPPS paralogs in A. thaliana genome. Accordingly, the changes in the expression patterns of the GGPPS paralogs occurring after gene duplication led to developmental and/or condition specific functional evolution.
The moss Physcomitrella patens is an important model organism to study plant evolution, development, physiology and biotechnology. Here, we have generated microarray gene expression data covering the principal developmental stages, culture forms and some environmental/stress conditions. Example analyses of developmental stages and growth conditions as well as abiotic stress treatments demonstrate that i) growth stage is dominant over culture conditions, ii) liquid culture is not stressful for the plant, iii) low pH might aid protoplastation by reduced expression of cell wall structure genes, iv) largely the same gene pool mediates response to de- and rehydration, and v) AP2/EREBP and NAC transcription factors play important roles in stress response reactions. With regard to the AP2 gene family, phylogenetic analysis and comparison with Arabidopsis thaliana shows commonalities as well as uniquely expressed family members under drought, light perturbations and protoplastation. Gene expression profiles for P. patens are available for the scientific community via the easy-to-use tool at "http://https://www.genevestigator.com" "https://www.genevestigator.com". By providing large scale expression profiles, the usability of this model organism is further enhanced, e.g. by enabling selection of control genes for quantitative Real Time PCR. Now, gene expression levels across a broad range of conditions can be accessed online for P. patens.
Plant growth and development are constantly influenced by temperature fluctuations. To respond to temperature changes, different levels of gene regulation are modulated in the cell. Alternative splicing (AS) is a widespread mechanism increasing transcriptome complexity and proteome diversity. Although genome-wide studies have revealed complex AS patterns in plants, whether AS impacts the stress defense of plants is not known. We used heat shock (HS) treatments at nondamaging temperature and messenger RNA sequencing to obtain HS transcriptomes in the moss Physcomitrella patens. Data analysis identified a significant number of novel AS events in the moss protonema. Nearly 50% of genes are alternatively spliced. Intron retention (IR) is markedly repressed under elevated temperature but alternative donor/acceptor site and exon skipping are mainly induced, indicating differential regulation of AS in response to heat stress. Transcripts undergoing heat-sensitive IR are mostly involved in specific functions, which suggests that plants regulate AS with transcript specificity under elevated temperature. An exonic GAG-repeat motif in these IR regions may function as a regulatory cis-element in heat-mediated AS regulation. A conserved AS pattern for HS transcription factors in P. patens and Arabidopsis (Arabidopsis thaliana) reveals that heat regulation for AS evolved early during land colonization of green plants. Our results support that AS of specific genes, including key HS regulators, is fine-tuned under elevated temperature to modulate gene regulation and reorganize metabolic processes.
Activists destroyed experimental fields of rapeseed plants in France this week to protest growing of mutated crops, national oilseed researcher Cetiom said. (Anti-GMO activists destroy rapeseed trial crops in France.
Jean-Pierre Zryd's insight:
They probably would like to destroy all agriculture - it's just a step further
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