531. Digital PCR as an effective tool for GMO quantification in complex matricesAlexandra Bogožalec Košir, Tina Demšar, Dejan Štebih, Jana Žel, Mojca Milavec, 2019, original scientific article Abstract: The increased use of genetically modified organisms (GMOs) is accompanied by increased complexity of the matrices that contain GMOs. The most common DNA-based approach for GMO detection and quantification is real-time quantitative polymerase chain reaction (qPCR). However, as qPCR is sensitive to inhibitors and relies on standard curves for quantification, it has limited application in GMO quantification for complex matrices. To overcome this hurdle in DNA quantification, we present droplet digital PCR (ddPCR) assays that were designed to target ‘Roundup Ready’ soybean and the soybean reference gene. Three ddPCR assays were transferred from qPCR to QX100/QX200 ddPCR platforms and characterised. Together, the fitness-for-purpose study on four real-life samples and the use of a chamber-based PCR system, showed that dPCR has great potential to improve such measurements in GMO testing and monitoring of food authenticity. Keywords: genetically modified organisms, digital PCR, GMO quantification, complex matrices Published in DiRROS: 23.07.2024; Views: 171; Downloads: 93
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532. Poročilo o preskusu št.: LVG 2024-074 : vzorec št. 2024/00385Nikica Ogris, Špela Hočevar, Patricija Podkrajšek, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, Fusarium circinatum, Pinus, borov smolasti rak, PCR Published in DiRROS: 23.07.2024; Views: 182; Downloads: 0 This document has many files! More... |
533. Cold atmospheric plasma as a novel method for inactivation of potato virus Y in water samplesArijana Filipić, Gregor Primc, Rok Zaplotnik, Nataša Mehle, Ion Gutiérrez-Aguirre, Maja Ravnikar, Miran Mozetič, Jana Žel, David Dobnik, 2019, original scientific article Abstract: While one of the biggest problems we are facing today is water scarcity, enormous quantities of water are still being used in irrigation. If contaminated, this water can act as an effective pathway for the spread of disease-causing agents, like viruses. Here, we present a novel, environmentally friendly method known as cold atmospheric plasma for inactivation of viruses in water used in closed irrigation systems. We measured the plasma-mediated viral RNA degradation as well as the plasma-induced loss of viral infectivity using potato virus Y as a model virus due to its confirmed water transmissibility and economic as well as biological importance. We showed that only 1 min of plasma treatment is sufficient for successful inactivation of viruses in water samples with either high or low organic background. The plasma-mediated inactivation was efficient even at markedly higher virus concentrations than those expected in irrigation waters. Obtained results point to reactive oxygen species as the main mode of viral inactivation. Our laboratory-scale experiments confirm for the first time that plasma has an excellent potential as the eukaryotic virus inactivation tool for water sources and could thus provide a cost-effective solution for irrigation mediated plant virus transmission. The outstanding inactivation efficiency demonstrated by plasma treatments in water samples offers further expansions of its application to other water sources such as reused wastewater or contaminated drinking waters, as well as other plant, animal, and human waterborne viruses, ultimately leading to the prevention of water scarcity and numerous human, animal, and plant infections worldwide. Keywords: cold atmospheric plasma, potato virus Y, virus inactivation, water decontamination Published in DiRROS: 23.07.2024; Views: 152; Downloads: 122
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534. Poročilo o preskusu št.: LVG 2024-072 : vzorec št. 2024/00313Tine Hauptman, Špela Hočevar, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, program preiskav, Geosmithia morbida, bolezen tisočerih rakov, vektorji, rtPCR Published in DiRROS: 23.07.2024; Views: 161; Downloads: 0 This document has many files! More... |
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537. Poročilo o preskusu št.: LVG 2024-063 : vzorec št. 2024/00185Tine Hauptman, Špela Hočevar, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, program preiskav, Geosmithia morbida, bolezen tisočerih rakov, vektorji, rtPCR Published in DiRROS: 23.07.2024; Views: 142; Downloads: 0 This document has many files! More... |
538. Who cares about ocean acidification in the Plasticene?Rachel Tiller, Francisco Arenas, Charles Galdies, Francisco Leitão, Alenka Malej, Beatriz Martinez Romera, Cosimo Solidoro, Robert Stojanov, Valentina Turk, Roberta Guerra, 2019, original scientific article Abstract: Plastics is all the rage, and mitigating marine litter is topping the agenda for nations pushing issues such as ocean acidification, or even climate change, away from the public consciousness. We are personally directly affected by plastics and charismatic megafauna is dying from it, and it is something that appears to be doable. So, who cares about the issue of ocean acidification anymore? We all should. The challenge is dual in the fact that is both invisible to the naked eye and therefore not felt like a pressing issue to the public, thereby not reaching the top of the agenda of policy makers; but also that it is framed in the climate change narrative of fear - whereby it instills in a fight-or-flight response in the public, resulting in their avoidance of the issue because they feel they are unable to take action that have results. In this article, we argue that the effective global environmental governance of ocean acidification, though critical to address, mitigate against and adapt to, is hindered by the both this lack of perception of urgency in the general public, fueled by a lack of media coverage, as well as a fight-or-flight response resulting from fear. We compare this to the more media friendly and plastics problem that is tangible and manageable. We report on a media plots of plastics and ocean acidification coverage over time and argue that the issue needs to be detangled from climate change and framed as its own issue to reach the agenda at a global level, making it manageable to assess and even care about for policy makers and the public alike? Keywords: oceans, acidification, plastics Published in DiRROS: 23.07.2024; Views: 133; Downloads: 68
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539. Genomic characterisation of the new Dickeya fangzhongdai species regrouping plant pathogens and environmental isolatesŠpela Alič, Jacques Pédron, Tanja Dreo, Frédérique van Gijsegem, 2019, original scientific article Abstract: Background
The Dickeya genus is part of the Pectobacteriaceae family that is included in the newly described enterobacterales order. It comprises a group of aggressive soft rot pathogens with wide geographic distribution and host range. Among them, the new Dickeya fangzhongdai species groups causative agents of maceration-associated diseases that impact a wide variety of crops and ornamentals. It affects mainly monocot plants, but D. fangzhongdai strains have also been isolated from pear trees and water sources. Here, we analysed which genetic novelty exists in this new species, what are the D. fangzhongdai-specific traits and what is the intra-specific diversity.
Results
The genomes of eight D. fangzhongdai strains isolated from diverse environments were compared to 31 genomes of strains belonging to other Dickeya species. The D. fangzhongdai core genome regroups approximately 3500 common genes, including most genes that encode virulence factors and regulators characterised in the D. dadantii 3937 model strain. Only 38 genes are present in D. fangzhongdai and absent in all other Dickeyas. One of them encodes a pectate lyase of the PL10 family of polysaccharide lyases that is found only in a few bacteria from the plant environment, soil or human gut. Other D. fangzhongdai-specific genes with a known or predicted function are involved in regulation or metabolism.
The intra-species diversity analysis revealed that seven of the studied D. fangzhongdai strains were grouped into two distinct clades. Each clade possesses a pool of 100–150 genes that are shared by the clade members, but absent from the other D. fangzhongdai strains and several of these genes are clustered into genomic regions. At the strain level, diversity resides mainly in the arsenal of T5SS- and T6SS-related toxin-antitoxin systems and in secondary metabolite biogenesis pathways.
Conclusion
This study identified the genome-specific traits of the new D. fangzhongdai species and highlighted the intra-species diversity of this species. This diversity encompasses secondary metabolites biosynthetic pathways and toxins or the repertoire of genes of extrachromosomal origin. We however didn’t find any relationship between gene content and phenotypic differences or sharing of environmental habitats.
Background
Soft rot Pectobacteriaceae are Enterobacterales responsible for considerable economic losses in several important crops and ornamental plants [1,2,3]. Their virulence is mainly due to the production and secretion of a battery of plant cell wall degrading enzymes (PCWDEs) that cause maceration of the plant tissue; however, several other virulence factors have also been characterized [2, 4]. These bacteria often exhibit a very broad host range, and recent outbreaks in potato, for example, resulted from the action of a cohort of bacteria belonging to different Pectobacteriaceae species in a complex population dynamics history [5]. The Pectobacteriaceae family includes two genera comprising soft rot bacteria, Pectobacterium and Dickeya. The Dickeya genus was formed in 2005 by the reclassification of former Erwinia chrysanthemi into six species [6]. It has recently undergone multiple phylogenetic changes, including the addition of three new species, Dickeya solani [7], Dickeya aquatica [8] and, more recently, Dickeya fangzhongdai [9].
The description of this last new species was based on three isolates from pear trees in China with bleeding canker necrosis [9], but it was extended by a large number of strains isolated from monocot plants from Japan [10, 11]. D. fangzhongdai strains were associated with soft rot symptoms of many ornamental and economically important staple food plants [10, 12, 13], thereby highlighting the broad host range of the species.
While there is little information regarding associated economic damages and the extent of its occurrence in different host plants outside of Asia, Alič et al. [14] recently identified D. fangzhongdai as the causative agent of soft rot of orchids in commercial production in Europe, starting with material from Asia [11]. Moreover, as previously reported, bacteriophages of different families, and active against D. fangzhongdai, were isolated from a wastewater treatment plant not associated to the orchid production site. This would suggest that D. fangzhongdai bacteria may be more widespread in nature than could currently be concluded on the basis of symptoms in plants. Its occurrence in water would suggest that it may potentially have a wider ecological niche than genomically close Dickeya spp., that is, Dickeya dadantii, Dickeya dianthicola, and D. solani.
Previous experience with D. solani has shown that novel species or isolates can lead to clonal spread and high losses in affected host plants [15]. Together with repeated introductions of D. fangzhongdai, the co-occurrence of genetically and phenotypically diverse strains on the same plants (e.g., B16 and S1 on orchids, as reported by Alič et al. [11]) increases the probability of the development of recombined strains with novel pathogenic potential and may present a risk to agriculturally important plants. Their aggressiveness, high maceration potential on various plant tissues, and persistence in potato plants further exacerbate the risk for agriculture.
Therefore, in this paper, we analysed the genomic characteristics of the D. fangzhongdai species, compared it to the other Dickeya species and determine the inter- and intra- species diversity. The study addressed the question whether the presence of the isolates in a specific environment is associated to a specific set of genes (water vs plant symptoms, monocots vs dicots, different geographical origin). We also analysed the virulence gene arsenal, in order to evaluate the virulence potential of this species.
Methods
Dickeya strain selection
All D. fangzhongdai genomes publicly available in the NCBI database were included in this study. These genomes were compared to five D. solani, four D. dadantii, five D. dianthicola, five D. chrysanthemi, seven D. zeae, one D. aquatica, two D. paradisiaca and two unassigned Dickeya genomes extracted from the NCBI database. Information on the provenance and genomic data of the D. fangzhongdai strains used in this study are summarized in Table 1. The accession numbers and phylogenetic position of the other Dickeya strains used for the SiLix analyses are presented in Additional file 1: Figure S1. Keywords: T5SS, T6SS, NRPS/PKS, zeamine, oocydin A, plant-bacteria interactions, plasmid, Dickeya fangzhongdai Published in DiRROS: 23.07.2024; Views: 167; Downloads: 118
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540. Poročilo o preskusu št.: LVG 2024-055 : vzorec št. 2024/00136Tine Hauptman, Špela Hočevar, Zina Devetak, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, program preiskav, Geosmithia morbida, bolezen tisočerih rakov, vektorji, rtPCR Published in DiRROS: 23.07.2024; Views: 140; Downloads: 0 This document has many files! More... |