Can consumers avoid mislabelling? Genetic species identification provides recommendations for shrimp/prawn products.

BACKGROUND: Crustaceans of the superfamily Penaeoidea (e.g., shrimps and prawns) are among the most commercially available aquatic products worldwide. However, there are few studies regarding not only the presence but also the characteristics of mislabelling in these food products. Such information would be helpful for consumers in order to avoid the typical problems associated with mislabelling (e.g., health and economic issues). For this reason, this work considers Penaeoidea mislabelling by comparing different products (frozen, fresh, boiled), and sources (hypermarkets, supermarkets and fishmongers) from Spain (Europe). RESULTS: A total of 94 samples from 55 different products were collected, representing 19 different species from 13 genera. Mitochondrial DNA (COI gene) was amplified, revealing mislabelling in almost 30% of supermarket products and almost exclusively found in frozen samples (95% of the total) regardless of its price. In addition, products from the Pacific Ocean seem to be particularly susceptible to mislabelling. CONCLUSIONS: All in all, recommendations for the consumer in order to avoid mislabelling of prawns include purchasing them fresh from fishmongers; aquaculture products must not be avoided. This study represents, to our knowledge, the first attempt to provide recommendations to consumers based on DNA analyses in order to avoid mislabelling in food products. Further research is therefore required to provide such recommendations in different food products, particularly those that are processed, packaged and/or frozen. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Beta-Lactam Antibiotic Resistance Genes in the Microbiome of the Public Transport System of Quito, Ecuador.

Multidrug-resistant bacteria present resistance mechanisms against ß-lactam antibiotics, such as Extended-Spectrum Beta-lactamases (ESBL) and Metallo-ß-lactamases enzymes (MBLs) which are operon encoded in Gram-negative species. Likewise, Gram-positive bacteria have evolved other mechanisms through mec genes, which encode modified penicillin-binding proteins (PBP2). This study aimed to determine the presence and spread of ß-lactam antibiotic resistance genes and the microbiome circulating in Quito's Public Transport (QTP). A total of 29 station turnstiles were swabbed to extract the surface environmental DNA. PCRs were performed to detect the presence of 13 antibiotic resistance genes and to identify and to amplify 16S rDNA for barcoding, followed by clone analysis, Sanger sequencing, and BLAST search. ESBL genes blaTEM-1 and blaCTX-M-1 and MBL genes blaOXA-181 and mecA were detected along QPT stations, blaTEM being the most widely spread. Two subvariants were found for blaTEM-1, blaCTX-M-1, and blaOXA-181. Almost half of the circulating bacteria found at QPT stations were common human microbiota species, including those classified by the WHO as pathogens of critical and high-priority surveillance. ß-lactam antibiotic resistance genes are prevalent throughout QPT. This is the first report of blaOXA-181 in environmental samples in Ecuador. Moreover, we detected a new putative variant of this gene. Some commensal coagulase-negative bacteria may have a role as mecA resistance reservoirs.

Genetic Variability of Polypedilum (Diptera: Chironomidae) from Southwest Ecuador.

Chironomids show a wide distribution and can occupy several habitats due to their high adaptive capacity in different freshwater environments. The genus Polypedilum is found along a wide elevational and environmental gradient in the neotropics, and its genetic variability could help to elucidate factors determining its distribution and tolerance to the environmental changes of different species or populations. This study examines the genetic variability of Polypedilum in an important biogeographic area that acts as a geographical barrier of biodiversity at the border of the Choco and Tumbes biomes. We identified five Polypedilum morphotypes using classic taxonomic methods. We examined 68 Polypedilum individuals from eight sampling sites in El Oro Province, Ecuador, analyzing the putative molecular species using the cytochrome c oxidase subunit 1 (CO1) mitochondrial gene fragment. Then, we calculated molecular diversity indices, Haplotype diversity (Hd), and θs and θπ estimators. Seven Polypedilum OTUs were determined from which a high molecular diversity was registered. A CCA was conducted to understand the population composition in relation to environmental characteristics. Results indicated that dissolved oxygen and temperature are the main environmental factors affecting Polypedilum distribution across elevational gradients and between basins.

Bioremediation potential of glyphosate-degrading microorganisms in eutrophicated Ecuadorian water bodies.

Phosphonate compounds are the basis of many xenobiotic pollutants, such as Glyphosate (N-(phosphonomethyl-glycine). Only procaryotic microorganisms and the lower eukaryotes are capable of phosphonate biodegradation through C-P lyase pathways. Thus, the aim of this study was to determine the presence of C-P lyase genes in Ecuadorian freshwater systems as a first step towards assessing the presence of putative glyphosate degraders. To that end, two Nested PCR assays were designed to target the gene that codifies for the subunit J (phnJ), which breaks the C-P bond that is critical for glyphosate mineralization. The assays designed in this study led to the detection of phnJ genes in 7 out of 8 tested water bodies. The amplified fragments presented 85-100% sequence similarity with phnJ genes that belong to glyphosate-degrading microorganisms. Nine sequences were not reported previously in the GenBank. The presence of phosphonate degraders was confirmed by isolating three strains able to grow using glyphosate as a unique carbon source. According to the 16S sequence, these strains belong to the Pantoea, Pseudomonas, and Klebsiella genera. Performing a Nested PCR amplification of phnJ genes isolated from eutrophicated water bodies, prior to isolation, may be a cost-effective strategy for the bioprospection of new species and/or genes that might have new properties for biotech industries, laying the groundwork for additional research.

Effect of thermal liquefaction on quality, chemical composition and antibiofilm activity against multiresistant human pathogens of crystallized eucalyptus honey.

Thermal liquefaction is a conventional method used by beekeepers to liquefy crystallized honey. However, an abusive use of heat may affect its quality, chemical composition and bioactivity. The purpose of this study was to investigate the effect of thermal liquefaction on the quality, chemical composition and antibiofilm properties of eucalyptus honey. Thermal liquefaction (at 45 and 60 °C) did not affect the honey's quality; however, a significant reduction in the reducing capacity, total phenolic content and hydrogen peroxide content was observed. At 60 °C, a significant reduction in the honey's ability to inhibit biofilm formation was observed in Pseudomonas aeruginosa, as well as a reduction in its ability to remove preformed biofilms in both Staphylococcus aureus and Pseudomonas aeruginosa. Structural changes in biofilm architecture caused by honey were not affected by thermal treatment. Therefore, we recommend liquefaction at 45 °C as the most convenient for honey liquefaction without affecting its characteristics.

Genetic barcoding of Ecuadorian epilithic diatom species suitable as water quality bioindicators.

Diatom identification is a key step in using these microorganisms as water quality bioindicators. Morphological diagnosis is a difficult task due to the enormous number of species and their microscopic size. This can be overcome using molecular tools to complement the diagnosis. The main goal of this work was to obtain the DNA barcode of Ecuadorian epilithic diatoms with a wide geographical distribution, a well-defined ecological range and characteristics that allow them to be reliable indicator species. Unialgal diatom cultures were obtained from environmental samples of Ecuadorian Andean streams. Morphological characterization of cultures was carried out under SEM microscopy. For molecular characterization, 18SV4 and rbcL barcodes were sequenced from each strain and blasted against a GenBank database. A phylogenetic tree for each barcode was constructed using the ML method including sequences of strains of the studied species from different geographical locations. The results showed the following five species to be suitable as bioindicators and these were isolated. Sellaphora seminulum (strain JA01b, c), Nitzschia fonticola (strain SP02a) and N. palea (strain CA01a) are tolerant to eutrophication; Eolimna minima (strain CH02a) is a mesotrophic water bioindicator, and Achnanthidium minutissimum (strain JA01a) is an oligotrophic water bioindicator. The comparison with the GenBank database of the barcoding regions supported the morphological identification. The barcoding sequences of the strains showed a high percentage of identity with the sequences reported in INSDC databases for the same species. The topology of the phylogenetic trees demonstrates that epilithic diatoms from Ecuador are closely related to those of same species isolated from other geographical regions. This study is a first attempt to establish a morphological and molecular taxonomic reference library for neotropical diatoms. This study demonstrates that it would be feasible to use the existing barcoding data for diatoms to develop molecular tools for the bioassessment of aquatic ecosystems in the Ecuadorian Andean region.

L'identification des diatomées est une étape clé dans l'utilisation de ces microorganismes comme bioindicateurs de la qualité de l'eau. Le diagnostic morphologique est une tâche difficile en raison du nombre considérable d'espèces et de leur dimension microscopique. Il est possible de surmonter cette difficulté en utilisant des techniques moléculaires pour compléter le diagnostic. L'objectif principal de ce travail était d'obtenir le code-barre de l'ADN des diatomées épilithiques équatoriennes ayant une large distribution géographique, une niche écologique bien définie et des caractéristiques leur permettant d'être des espèces indicatrices fiables. Des cultures de diatomées unialgales ont été obtenues à partir d'échantillons environnementaux de cours d'eau des Andes équatoriennes. La caractérisation morphologique des cultures a été réalisée sous microscopie MEB. Pour la caractérisation moléculaire, les codes-barres 18SV4 et rbcL ont été séquencés à partir de chaque souche et comparés à la base de données GenBank. Pour chaque code-barres, un arbre phylogénétique a été construit à partir de la méthode ML comprenant des séquences de souches des espèces étudiées, provenant de différents lieux géographiques. Les résultats ayant montré que les cinq espèces suivantes étaient appropriées comme bioindicateurs, elles ont été isolées. Sellaphora seminulum (souche JA01b, c), Nitzschia fonticola (souche SP02a) et N. palea (souche CA01a) sont tolérantes à l'eutrophisation ; Eolimna minima (souche CH02a) est un bioindicateur d'eau mésotrophe, et Achnanthidium minutissimum (souche JA01a) est un bioindicateur d'eau oligotrophe. La comparaison avec la base de données GenBank des régions de code-barres a supporté leurs identifications morphologiques. Les séquences de code-barres des souches ont montré un pourcentage élevé d'identité génétique avec les séquences signalées dans les bases de données de l'INSDC pour la même espèce. La topologie des arbres phylogénétiques démontre que les diatomées épilithiques de l'Équateur sont étroitement liées à celles des mêmes espèces isolées d'autres régions géographiques. Cette étude est une première tentative d'établir une bibliothèque de référence morphologique et taxonomique moléculaire pour les diatomées néotropicales. Cette étude démontre qu'il serait possible d'utiliser les données de code-barres existantes pour les diatomées afin de développer des instruments moléculaires pour la bioévaluation des écosystèmes aquatiques dans la région andine équatorienne.

SARS-CoV-2 in river water: Implications in low sanitation countries.

Since the beginning of COVID-19 pandemic studies on viral shedding have reported that this virus is excreted in feces in most patients. High viral loads are found at the sewage pipeline or at the entrance of wastewater treatment plants from cities where the number of COVID-19 cases are significant. In Quito (Ecuador) as in many other cities worldwide, wastewater is directly discharged into natural waters. The aim of this study was to evaluate SARS-CoV-2 presence in urban streams from a low sanitation context. Three river locations along the urban rivers of Quito were sampled on the 5th of June during a peak of COVID-19 cases. River samples were evaluated for water quality parameters and afterwards, concentrated for viral analysis using skimmed milk flocculation method. The viral concentrates were quantified for SARS-CoV-2 (N1 and N2 target regions) and Human Adenovirus as a human viral indicator. The results showed that SARS-CoV-2 was detected for both target regions in all samples analyzed in a range of 2,91E+05 to 3,19E+06 GC/L for N1 and from 2,07E+05 to 2,22E+06 GC/L for N2. The high values detected in natural waters from a low sanitation region have several implications in health and ecology that should be further assessed.

Protective effect of the medicinal herb infusion "horchata" against oxidative damage in cigarette smokers: An ex vivo study.

Cigarette smoking has been associated with an increase in oxidative stress (OS) and is considered a predisposing factor to chronic noncommunicable diseases, whilst dietary antioxidants has been proposed as an alternative to cope with this oxidative stress. In this study, 20 smokers and 20 non-smokers were studied with the aim of determining their antioxidant status, as well as the ability of an infusion of 23 medicinal plants, to counteract the damage caused by OS. The plasma, red blood cells (RBCs) and polymorphonuclear cells (PBMCs) of both groups were incubated or not with the horchata infusion extract and then the OS markers, genotoxicity, nanostructure of RBCs membrane and genes related to oxidative responses and cellular functionality were evaluated. Up to 33 different compounds, mainly quercetin glycosides, were identified in the extract. A significant deterioration in the antioxidant status in smokers compared to non-smokers was found. The horchata infusion extract improved the nanostructure of RBCs and DNA damage, as well as the activity of the endogenous antioxidant enzymes and markers of oxidative damage to lipid, and proteins in plasma, RBCs and PBMCs in both groups, whilst no significant changes were found in the expression of different genes related to OS response.

Eucalyptus honey: Quality parameters, chemical composition and health-promoting properties.

Eucalyptus honey is an important unifloral honey commercialized worldwide and much desired by consumers due to the medicinal properties attributed to it because of the plant from which it is produced. In general, eucalyptus honey has been classified as being rich in pollen grains from the eucalyptus tree as well as having physicochemical characteristics that, in a way, have made it stand out from other honeys. Similar to other types of honey, eucalyptus honey can suffer contaminations and adulterations that compromise its quality, safety and authenticity. Thus, detailed knowledge of the composition and properties of this monofloral honeys is of great importance. With this background, the aim of this review is to present and discuss recent data regarding the physicochemical characteristics, chemical and health-promoting properties of eucalyptus honey as well as microbial contamination, authenticity, processing and adulteration.

Changes Induced by Pressure Processing on Immunoreactive Proteins of Tree Nuts.

Tree nuts confer many health benefits due to their high content of vitamins and antioxidants, and they are increasingly consumed in the last few years. Food processing is an important industrial tool to modify allergenic properties of foods, in addition to ensuring safety and enhancing organoleptic characteristics. The effect of high pressure, without and with heating, on SDS-PAGE and immunodetection profile of potential allergenic proteins (anti-11S, anti-2S and anti-LTP) of pistachio, cashew, peanut, hazelnut, almond, and chestnut was investigated. Processing based on heat and/or pressure and ultra-high pressure (HHP, 300-600 MPa) without heating was applied. After treating the six tree nuts with pressure combined with heat, a progressive diminution of proteins with potential allergenic properties was observed. Moreover, some tree nuts proteins (pistachio, cashew, and peanut) seemed to be more resistant to technological processing than others (hazelnut and chestnut). High pressure combined with heating processing markedly reduce tree nut allergenic potential as the pressure and treatment time increases. HHP do not alter hazelnut and almond immunoreactivity.

Application of real-time PCR for tree nut allergen detection in processed foods.

Currently, food allergies are an important health concern worldwide. The presence of undeclared allergenic ingredients or the presence of traces of allergens due to accidental contamination during food processing poses a great health risk to sensitized individuals. Therefore, reliable analytical methods are required to detect and identify allergenic ingredients in food products. Real-time PCR allowed a specific and accurate amplification of allergen sequences. Some processing methods could induce the fragmentation and/or degradation of genomic DNA and some studies have been performed to analyze the effect of processing on the detection of different targets, as thermal treatment, with and without applying pressure. In this review, we give an updated overview of the applications of real-time PCR for the detection of allergens of tree nut in processed food products. The different variables that contribute to the performance of PCR methodology for allergen detection are also review and discussed.

Influence of enzymatic hydrolysis on the allergenic reactivity of processed cashew and pistachio.

Cashew and pistachio allergies are considered a serious health problem. Previous studies have shown that thermal processing, pressurization and enzymatic hydrolysis may reduce the allergenic properties of food by changing the protein structure. This study assesses the allergenic properties of cashew and pistachio after thermal treatment (boiling and autoclaving), with or without pressure (autoclaving), and multiple enzymatic treatments under sonication, by SDS-PAGE, western blot and ELISA, with serum IgE of allergic individuals, and mass spectroscopy. Autoclaving and enzymatic hydrolysis under sonication separately induced a measurable reduction in the IgE binding properties of pastes made from treated cashew and pistachio nuts. These treatments were more effective with pistachio allergens. However, heat combined with enzymatic digestion was necessary to markedly lower IgE binding to cashew allergens. The findings identify highly effective simultaneous processing conditions to reduce or even abolish the allergenic potency of cashew and pistachio.

Thermal processing effects on the IgE-reactivity of cashew and pistachio.

Thermal processing can modify the structure and function of food proteins and may alter their allergenicity. This work aimed to elucidate the influence of moist thermal treatments on the IgE-reactivity of cashew and pistachio. IgE-western blot and IgE-ELISA were complemented by Skin Prick Testing (SPT) and mediator release assay to determine the IgE cross-linking capability of treated and untreated samples. Moist thermal processing diminished the IgE-binding properties of both nuts, especially after heat/pressure treatment. The wheal size in SPT was importantly reduced after application of thermally-treated samples. For cashew, heat/pressure treated-samples still retain some capacity to cross-link IgE and degranulate basophils, however, this capacity was diminished when compared with untreated cashew. For pistachio, the degranulation of basophils after challenge with the harshest heat/pressure treatment was highly decreased. Boiling produced more variable results, however this treatment applied to both nuts for 60 min, led to an important decrease of basophil degranulation.

Detection by real time PCR of walnut allergen coding sequences in processed foods.

A quantitative real-time PCR (RT-PCR) method, employing novel primer sets designed on Jug r 1, Jug r 3, and Jug r 4 allergen-coding sequences, was set up and validated. Its specificity, sensitivity, and applicability were evaluated. The DNA extraction method based on CTAB-phenol-chloroform was best for walnut. RT-PCR allowed a specific and accurate amplification of allergen sequence, and the limit of detection was 2.5pg of walnut DNA. The method sensitivity and robustness were confirmed with spiked samples, and Jug r 3 primers detected up to 100mg/kg of raw walnut (LOD 0.01%, LOQ 0.05%). Thermal treatment combined with pressure (autoclaving) reduced yield and amplification (integrity and quality) of walnut DNA. High hydrostatic pressure (HHP) did not produce any effect on the walnut DNA amplification. This RT-PCR method showed greater sensitivity and reliability in the detection of walnut traces in commercial foodstuffs compared with ELISA assays.

Transcriptional profiles of Arabidopsis stomataless mutants reveal developmental and physiological features of life in the absence of stomata.

Loss of function of the positive stomata development regulators SPCH or MUTE in Arabidopsis thaliana renders stomataless plants; spch-3 and mute-3 mutants are extreme dwarfs, but produce cotyledons and tiny leaves, providing a system to interrogate plant life in the absence of stomata. To this end, we compared their cotyledon transcriptomes with that of wild-type plants. K-means clustering of differentially expressed genes generated four clusters: clusters 1 and 2 grouped genes commonly regulated in the mutants, while clusters 3 and 4 contained genes distinctively regulated in mute-3. Classification in functional categories and metabolic pathways of genes in clusters 1 and 2 suggested that both mutants had depressed secondary, nitrogen and sulfur metabolisms, while only a few photosynthesis-related genes were down-regulated. In situ quenching analysis of chlorophyll fluorescence revealed limited inhibition of photosynthesis. This and other fluorescence measurements matched the mutant transcriptomic features. Differential transcriptomes of both mutants were enriched in growth-related genes, including known stomata development regulators, which paralleled their epidermal phenotypes. Analysis of cluster 3 was not informative for developmental aspects of mute-3. Cluster 4 comprised genes differentially up-regulated in mute-3, 35% of which were direct targets for SPCH and may relate to the unique cell types of mute-3. A screen of T-DNA insertion lines in genes differentially expressed in the mutants identified a gene putatively involved in stomata development. A collection of lines for conditional overexpression of transcription factors differentially expressed in the mutants rendered distinct epidermal phenotypes, suggesting that these proteins may be novel stomatal development regulators. Thus, our transcriptome analysis represents a useful source of new genes for the study of stomata development and for characterizing physiology and growth in the absence of stomata.

Timely expression of the Arabidopsis stoma-fate master regulator MUTE is required for specification of other epidermal cell types.

Epidermal differentiation in Arabidopsis thaliana aerial organs involves stomatal lineage development. Lineages derive from meristemoids, which arise from asymmetric divisions of protodermal cells. Each meristemoid divides repeatedly in an inward spiral before it transits to a guard mother cell (GMC) that produces the stoma, leaving a trail of surrounding stomatal lineage ground cells (SLGCs) that eventually differentiate into endoreplicated pavement cells. MUTE is a bHLH transcription factor that is expressed in late meristemoids and drives their transition to GMCs. Loss-of-function mute mutants are stomata-less dwarf plants with arrested lineages, in which stunted putative SLGCs surround a halted meristemoid. We analysed MUTE functions using a chemically inducible system for mute-3 complementation based on conditional MUTE expression in its normal domain. Continuous induction from germination produced stomata-bearing, normal-sized plants with viable mute-3 seeds. In 2-week-old mute-3 cotyledons, meristemoids appeared to retain their identity and synchronously formed stomata in response to induced MUTE expression. However, arrested SLGCs were not complemented: many produced stomata, leading to stomatal clusters, and others remained unexpanded and diploid. In contrast, non-lineage pavement cells, which are under-endoreplicated in mute-3, expanded and increased their ploidy level upon induction, showing that the lack of response of SLGCs is specific to this arrested cell type. Leaf phenotypic mosaics include wild-type lineages and adjacent mute-3 lineages, whose meristemoids and putative SLGCs remained arrested, indicating that the role of MUTE in SLGC fate is strictly lineage-autonomous. These results show that timely MUTE expression is essential to prevent stomatal fate in SLGCs and to promote their differentiation as pavement cells.

Specialized functions of the PP2A subfamily II catalytic subunits PP2A-C3 and PP2A-C4 in the distribution of auxin fluxes and development in Arabidopsis.

Protein phosphorylation is a key molecular switch used to transmit information in biological signalling networks. The output of these signalling circuits is governed by the counteracting activities of protein kinases and phosphatases that determine the direction of the switch. Whereas many kinases have been functionally characterized, it has been difficult to ascribe precise cellular roles to plant phosphatases, which are encoded by enlarged gene families that may provide a high degree of genetic redundancy. In this work we have analysed the role in planta of catalytic subunits of protein phosphatase 2A (PP2A), a family encoded by five genes in Arabidopsis. Our results indicate that the two members of subfamily II, PP2A-C3 and PP2A-C4, have redundant functions in controlling embryo patterning and root development, processes that depend on auxin fluxes. Moreover, polarity of the auxin efflux carrier PIN1 and auxin distribution, determined with the DR5(pro) :GFP proxy, are affected by mutations in PP2A-C3 and PP2A-C4. Previous characterization of mutants in putative PP2A regulatory subunits had established a link between this class of phosphatases and PIN dephosphorylation and subcellular distribution. Building on those findings, the results presented here suggest that PP2A-C3 and PP2A-C4 catalyse this reaction and contribute critically to the establishment of auxin gradients for proper plant development.

Roles of constitutive photomorphogenic 10 in Arabidopsis stomata development.

Stomata are epidermal bi-celled structures that differentiate within special cell lineages initiated by a subset of protodermal cells. Recently, we showed that the Arabidopsis photomorphogenic repressor COP10 controls specific cell-lineage and cell-signaling developmental mechanisms in stomatal lineages. Loss-of-function cop10-1 mutant cotyledons and leaves produced (in the light and in the dark) abundant stomatal clusters, but nonlineage epidermal cells were not affected. Here we examine COP10 role in hypocotyls, cylindrical organs displaying a distinct epidermal organization with alternate files of protruding and non-protruding cells, with the latter producing a limited number of stomata. COP10 prevents stomatal clusters and restricts stomata production in hypocotyls; these roles are specific to lineage cells as in cotyledons, since COP10 loss of function does not elicit stomatal fate in nonlineage cells; COP10 also sustains the directional cell expansion of all hypocotyl epidermal cell types, and seems necessary for the differentiation between protruding and non-protruding cell files.

Dynamic analysis of epidermal cell divisions identifies specific roles for COP10 in Arabidopsis stomatal lineage development.

Stomatal development in Arabidopsis thaliana has been linked to photoreceptor-perceived light through several components of the photomorphogenic switch, whose lack of function is often seedling-lethal. CONSTITUTIVE PHOTOMORPHOGENIC 10 (COP10) is an important component of this switch, its loss of function producing stomatal clusters. Exploiting the reduced lethality of the cop10-1 mutant we characterized the developmental basis of its stomatal phenotype. Constitutive, light-independent stomata overproduction accounts for half of cop10-1 stomatal abundance and appears very early in development. Clusters are responsible for the remaining stomata excess and build-up progressively at later stages. Serial impressions of living cotyledon epidermis allowed a dynamic, quantitative analysis of stomatal lineage types by reconstructing their division histories. We found that COP10 adjusts the initiation frequency and extension of stomatal lineages (entry and amplifying asymmetric divisions) and represses stomatal fate in lineage cells; COP10 also supervises the orientation of spacing divisions in satellite lineages, preventing the appearance of stomata in contact. Aberrant accumulation of the proliferating stomatal lineage cell marker TMMpro::TMM-GFP showed that the abundant cop10-1 stomatal lineages maintained extended and ectopic competence for stomatal fate. Expression of stomatal development master genes suggests that the mutant does not bypass major molecular actors in this process. cop10-1 first leaf produces trichomes and apparently normal pavement cells, but functionally and morphologically aberrant stomata; COP10 operates genetically in parallel to the stomatal repressor SDD1 and does not generally affect epidermal cell differentiation, but seems to operate on stomatal lineages where it controls specific cell-lineage and cell-signaling developmental mechanisms.

Phylogenetic relationships among plant and animal parasites, and saprotrophs in Aphanomyces (Oomycetes).

Molecular phylogenetic relationships among 12 species of Aphanomyces de Bary (Oomycetes) were analyzed based on 108 ITS sequences of nuclear rDNA. Sequences used in the analyses belonged to the major species currently available in pure culture and GenBank. Bayesian, maximum likelihood, and maximum parsimony analyses support that Aphanomyces constitutes a monophyletic group. Three independent lineages were found: (i) plant parasitic, (ii) animal parasitic, and (iii) saprotrophic or opportunistic parasitic. Sexual reproduction appeared to be critical in plant parasites for survival in soil environments while asexual reproduction seemed to be advantageous for exploiting specialization in animal parasitism. Repeated zoospore emergence seems to be an advantageous property for both plant and animal parasitic modes of life. Growth in unspecific media was generally faster in saprotrophs compared with parasitic species. A number of strains and GenBank sequences were found to be misidentified. It was confirmed molecularly that Aphanomyces piscicida and Aphanomyces invadans appear to be conspecific, and found that Aphanomyces iridis and Aphanomyces euteiches are closely related, if not the same, species. This study has shown a clear evolutionary separation between Aphanomyces species that are plant parasites and those that parasitize animals. Saprotrophic or opportunistic species formed a separate evolutionary lineage except Aphanomyces stellatus whose evolutionary position has not yet been resolved.