19 results on '"Rossmann, Simeon"'
Search Results
2. Diversity of the Rysto gene conferring resistance to potato virus Y in wild relatives of potato
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Paluchowska, Paulina, Lim Rossmann, Simeon, Lysøe, Erik, Janiszewska, Marta, Michalak, Krystyna, Heydarnajad Giglou, Rasoul, Torabi Giglou, Mousa, Brurberg, May Bente, Śliwka, Jadwiga, and Yin, Zhimin
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- 2024
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3. Diseases Caused by Pectobacterium and Dickeya Species Around the World
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van der Wolf, Jan M., Acuña, Ivette, De Boer, Solke H., Brurberg, May B., Cahill, Greig, Charkowski, Amy O., Coutinho, Teresa, Davey, Triona, Dees, Merete W., Degefu, Yeshitila, Dupuis, Brice, Elphinstone, John G., Fan, Jiaqin, Fazelisanagri, Esmaeil, Fleming, Thomas, Gerayeli, Nahid, Gorshkov, Vladimir, Helias, Valérie, le Hingrat, Yves, Johnson, Steven B., Keiser, Andreas, Kellenberger, Isabelle, Li, Xiang (Sean), Lojkowska, Ewa, Martin, Rodney, Perminow, Juliana Irina, Petrova, Olga, Motyka-Pomagruk, Agata, Rossmann, Simeon, Schaerer, Santiago, Sledz, Wojciech, Toth, Ian K., Tsror, Leah, van der Waals, Jacquie E., de Werra, Patrice, Yedidia, Iris, Van Gijsegem, Frédérique, editor, van der Wolf, Jan M., editor, and Toth, Ian K., editor
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- 2021
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4. Pectobacterium and Dickeya: Environment to Disease Development
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Toth, Ian K., Barny, Marie-anne, Brurberg, May B., Condemine, Guy, Czajkowski, Robert, Elphinstone, John G., Helias, Valérie, Johnson, Steven B., Moleleki, Lucy N., Pirhonen, Minna, Rossmann, Simeon, Tsror, Leah, van der Waals, Jacquie E., van der Wolf, Jan M., Van Gijsegem, Frédérique, Yedidia, Iris, Van Gijsegem, Frédérique, editor, van der Wolf, Jan M., editor, and Toth, Ian K., editor
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- 2021
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5. Diversity of the Ry sto gene conferring resistance to potato virus Y in wild relatives of potato
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Paluchowska, Paulina, primary, Rossmann, Simeon Lim, additional, Lysøe, Erik, additional, Janiszewska, Marta, additional, Michalak, Krystyna, additional, Giglou, Rasoul Heydarnajad, additional, Giglou, Mousa Torabi, additional, Brurberg, May Bente, additional, Śliwka, Jadwiga, additional, and Yin, Zhimin, additional
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- 2024
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6. Genetic characterization of historic Norwegian Erwinia amylovoraisolates by SSR-genotyping
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Brurberg, May Bente, Elameen, Abdelhameed, Sletten, Arild, and Rossmann, Simeon Lim
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Erwinia amylovora, the causative agent of fire blight of pome fruits and other rosaceous plants belongs to the group of regulated quarantine pests. The aim of this work was to characterize the populations of E. amylovorain Norway and their geographical distribution. A total of 238 E. amylovoraisolates recovered from symptomatic host plants in Norway between 1986 and 2004 were genotyped by means of a short sequence repeat (SSR) marker (ATTACAGA) on plasmid pEa29. The SSR region was amplified and amplicon size determined using fluorescent labelling and rapid, automated capillary gel electrophoresis. All isolates contained the pEa29 plasmid harbouring the investigated marker. In total, ten genotypes were identified, of which two were detected only once. The number of repeats varied from 3 to 13, with 43% of the isolates containing five repeats. Of 17 isolates collected between 1986 and 1991, all but one contained five repeats, whereas more variation was observed in isolates from the period 2000 to 2004. Most of the isolates (80%) originated from Cotoneaster bullatus, hence no relationship between genotype of the isolate and host species that it was isolated from could be detected. This historic data suggests multiple introductions of E. amylovorato Norway.
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- 2024
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7. Diversity of the Rysto gene conferring resistance to potato virus Y in wild relatives of potato.
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Paluchowska, Paulina, Lim Rossmann, Simeon, Lysøe, Erik, Janiszewska, Marta, Michalak, Krystyna, Heydarnajad Giglou, Rasoul, Torabi Giglou, Mousa, Brurberg, May Bente, Śliwka, Jadwiga, and Yin, Zhimin
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POTATO virus Y , *POTATOES , *RELATIVES , *SOLANUM , *AMINO acid sequence , *CULTIVARS - Abstract
Background: Potato virus Y (PVY) is among the economically most damaging viral pathogen in production of potato (Solanum tuberosum) worldwide. The gene Rysto derived from the wild potato relative Solanum stoloniferum confers extreme resistance to PVY. Results: The presence and diversity of Rysto were investigated in wild relatives of potato (298 genotypes representing 29 accessions of 26 tuber-bearing Solanum species) using PacBio amplicon sequencing. A total of 55 unique Rysto-like sequences were identified in 72 genotypes representing 12 accessions of 10 Solanum species and six resistant controls (potato cultivars Alicja, Bzura, Hinga, Nimfy, White Lady and breeding line PW363). The 55 Rysto-like sequences showed 89.87 to 99.98% nucleotide identity to the Rysto reference gene, and these encoded in total 45 unique protein sequences. While Rysto-like26 identified in Alicja, Bzura, White Lady and Rysto-like16 in PW363 encode a protein identical to the Rysto reference, the remaining 44 predicted Rysto-like proteins were 65.93 to 99.92% identical to the reference. Higher levels of diversity of the Rysto-like sequences were found in the wild relatives of potato than in the resistant control cultivars. The TIR and NB-ARC domains were the most conserved within the Rysto-like proteins, while the LRR and C-JID domains were more variable. Several Solanum species, including S. antipoviczii and S. hougasii, showed resistance to PVY. This study demonstrated Hyoscyamus niger, a Solanaceae species distantly related to Solanum, as a host of PVY. Conclusions: The new Rysto-like variants and the identified PVY resistant potato genotypes are potential resistance sources against PVY in potato breeding. Identification of H. niger as a host for PVY is important for cultivation of this plant, studies on the PVY management, its ecology, and migrations. The amplicon sequencing based on PacBio SMRT and the following data analysis pipeline described in our work may be applied to obtain the nucleotide sequences and analyze any full-length genes from any, even polyploid, organisms. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Field-scale molecular testing of virulent potato soft rot Pectobacteriaceae in Norway
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Rossmann, Simeon, Dees, Merete Wiken, Torp, Torfinn, Le, Vinh Hong, Skogen, Monica, Glorvigen, Borghild, van der Wolf, Jan, and Brurberg, May Bente
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- 2020
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9. Genome analysis of Phytophthora cactorum strains associated with crown- and leather-rot in strawberry
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Gogoi, Anupam, primary, Rossmann, Simeon L., additional, Lysøe, Erik, additional, Stensvand, Arne, additional, and Brurberg, May Bente, additional
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- 2023
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10. Genomic signatures and insights into host niche adaptation of the entomopathogenic fungus Metarhizium humberi
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Iwanicki, Natasha Sant′Anna, primary, Botelho, Ana Beatriz Riguetti Zanardo, additional, Klingen, Ingeborg, additional, Júnior, Italo Delalibera, additional, Rossmann, Simeon, additional, and Lysøe, Erik, additional
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- 2021
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11. Pest risk categorization – New plant health regulations for Norway : Scientific Opinion of the Panel on Plant Health of the Norwegian Scientific Committee for Food and Environment
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Krokene, Paal, Hatteland, Bjørn Arild, Magnusson, Christer, Flø, Daniel, Thomsen, Iben M., Stenberg, Johan A., Brurberg, May Bente, Wendell, Micael, Nicolaisen, Mogens, Rossmann, Simeon, Talgø, Venche, Krokene, Paal, Hatteland, Bjørn Arild, Magnusson, Christer, Flø, Daniel, Thomsen, Iben M., Stenberg, Johan A., Brurberg, May Bente, Wendell, Micael, Nicolaisen, Mogens, Rossmann, Simeon, and Talgø, Venche
- Abstract
In an ongoing effort to renew Norwegian regulations related to plants and measures against plant pests, the Norwegian Food Safety Authority asked The Norwegian Scientific Committee for Food and Environment (VKM) which of the currently regulated pests that should still be regulated (either as a quarantine pest (QP) or a regulated non-quarantine pest (RNQP) for Norway), and whether there are any species that should be deregulated. Following such a risk categorization process the Norwegian Food Safety Authority will determine if pest risk assessments (PRA’s) should be performed for quarantine pests. International trade regulations define quarantine pests (QPs) as pests of potential economic importance to an area that are not yet present, or are present but not widely distributed and are subject to official control. A regulated non-quarantine pest (RNQP) is a pest whose presence in plants for planting affects the intended use of those plants with an economically unacceptable impact and which is therefore subject to official control within the territory of the importing contracting party and regulated in international trade. In this report VKM presents an overview of the pest categorisation of some of the pests regulated in the current Norwegian regulation and concludes on whether each pest should be regulated as a potential QP, RNQP or none of these categories for Norway. The pest categorisation process – the process of determining whether a pest has or has not the characteristics of a QP or RNQP – has been done using the FinnPRIO model. The FinnPRIO model is a pest risk ranking tool that uses a hypervolume approach carry out quick, semiquantitative expert assessments and that allows a high number of pest risk categorizations to be done cost-effectively and in a short period of time. In total 33 pests were assessed as per request from the Norwegian Food Safety Authority. Of those 33 pests VKM suggests that the vast majority – 32 pests – are kept as a QPs for Norway. How
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- 2021
12. Pectobacterium and Dickeya: Environment to Disease Development
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Toth, I.K., Barny, Marie-Anne, Brurberg, M.B., Condemine, G., Czajkowski, R.L., Elphinstone, J.G., Helias, V., Johnson, Steven B., Moleleki, Lucy N., Pirhonen, Minna, Rossmann, Simeon, Tsror, L., van der Waals, J.E., van der Wolf, J.M., van Gijsegem, Frédérique, Yedidia, Iris, Toth, I.K., Barny, Marie-Anne, Brurberg, M.B., Condemine, G., Czajkowski, R.L., Elphinstone, J.G., Helias, V., Johnson, Steven B., Moleleki, Lucy N., Pirhonen, Minna, Rossmann, Simeon, Tsror, L., van der Waals, J.E., van der Wolf, J.M., van Gijsegem, Frédérique, and Yedidia, Iris
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The soft rot Pectobacteriaceae (SRP) infect a wide range of plants worldwide and cause economic damage to crops and ornamentals but can also colonize other plants as part of their natural life cycle. They are found in a variety of environmental niches, including water, soil and insects, where they may spread to susceptible plants and cause disease. In this chapter, we look in detail at the plants colonized and infected by these pathogens and at the diseases and symptoms they cause. We also focus on where in the environment these organisms are found and their ability to survive and thrive there. Finally, we present evidence that SRP may assist the colonization of human enteric pathogens on plants, potentially implicating them in aspects of human/animal as well as plant health.
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- 2021
13. DNA Metabarcoding Reveals Broad Presence of Plant Pathogenic Oomycetes in Soil From Internationally Traded Plants
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Rossmann, Simeon, primary, Lysøe, Erik, additional, Skogen, Monica, additional, Talgø, Venche, additional, and Brurberg, May Bente, additional
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- 2021
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14. Field-scale molecular testing of virulent potato soft rot Pectobacteriaceae in Norway
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Rossmann, Simeon, primary, Dees, Merete Wiken, additional, Torp, Torfinn, additional, Le, Vinh Hong, additional, Skogen, Monica, additional, Glorvigen, Borghild, additional, van der Wolf, Jan, additional, and Brurberg, May Bente, additional
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- 2019
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15. Potato soft rot Pectobacteriaceae in Norway – seed potato health, association with insects and molecular mechanisms of disease development
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Rossmann, Simeon K. W., Brurberg, May Bente, Dees, Merete Wiken, Perminow, Juliana, and van der Wolf, Jan M.
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Pectobacteriaceae ,Blackleg ,Molecular biology ,Insect vectors ,Plant pathology ,Agriculture ,Potato ,Soft rot - Abstract
Soft rot Pectobacteriaceae are among the most problematic pathogens of a wide variety of crop plants and ornamentals. Among their hosts is potato, the most important food crop in Norway, where the bacteria cause soft rot of the tubers and blackleg of the stem. The soft rot Pectobacteriaceae currently comprise 18 recognized bacterial species of the genera Dickeya and Pectobacterium, which are somewhat diverse in aspects like geographical distribution, preferred temperature for growth and virulence, typical host range, as well as the disease symptoms they cause on different hosts. Nevertheless, they all feed on rotten host tissue, which they macerate by secreting a variety of plant cell wall degrading enzymes into the intercellular space. In this work, several aspects of soft rot Pectobacteriaceae biology and virulence were investigated with the ultimate goal of contributing to the improvement of potato seed health. To gain more insight into the taxonomy and phylogeny of these pathogens, the genome sequencing of two isolates, which appeared atypical in previous phylogenetic analysis, was performed. This lead to the description of the new species Pectobacterium polaris, which subsequently was found in old isolate collections in Poland and the Netherlands. The identification of this new species may lead to improved detection tools, which facilitate sensible management strategies. The health of Norwegian potato seed of varied quality and different cultivars was assessed in a three-year field study. This was done to investigate the influence of environmental and host factors, as well as testing the implementation of large scale molecular testing of the pathogens’ infection prevalence. The bacteria were found to be near-ubiquitous, regardless of potato cultivar or seed quality, except for seed of the highest quality. These tubers quite reliably tested low in infection prevalence and disease was rarely observed compared to lower quality seed. Climate, particularly precipitation seemed to play the most important role in infection prevalence. Disease incidence for blackleg was partially determined by the host, as demonstrated by one cultivar (Innovator), which seemed less susceptible to this disease. It also performed best in a test, where tubers from 15 different cultivars were infected with P. polaris and P. atrosepticum. In this test, it was also shown that temperature was the factor that had the overall largest influence on rot outcome. This study gave insight into the status of Norwegian seed potatoes in regard to soft rot and important environmental factors in disease. In addition, a two-year field study was performed to examine the presence of the pathogens in insects that were caught in potato fields. The insect were tested by qPCR, which allowed the selection of specimens which contained a high amount of bacteria. These insect were identified by DNA sequencing, and were found to belong to over 90 different species. In the two years, 15 and 20 % of tested insects contained a high amount of soft rot bacteria. A high percentage of insects in a field where clean seed potatoes were grown, was carrying the bacteria, which is highly relevant, because it is not clear how clean seed potatoes are initially infected. Remarkably, the seed corn maggot (Delia platura) was the species that most often carried a high amount of the bacteria. The same species and closely related flies were previously shown to transmit the bacteria to potato and other plants. By showing the high number of insects that carried the soft rot bacteria, and identifying the insects as known vector species, it was demonstrated that insects may play a much more important role in the infection of clean seed than previously assumed. Furthermore, the transcriptomes of the type strain of P. polaris, as well as a strain of P. carotovorum subsp. carotovorum were analysed during early and progressing tuber infection by RNA sequencing. This was done to examine the regulation of virulence factors in the bacteria over the development of disease. In both examined strains, important virulence genes, encoding e.g. the enzymes that degrade host cell walls, as well as several bacterial secretion systems, decreased in expression over time. This, indicated a shift in prioritized function in the investigated bacteria. A better understanding of the molecular processes and their trajectory in progressing infection may help in devising and optimizing counterstrategies. Bløtråtebakterier er blant de mest problematiske skadegjørere i mange forskjellige kulturplanter, inkludert potet der de forårsaker sykdommene bløtråte og stengelråte. Bløtråtebakterier består per i dag av 18 kjente bakteriearter fra slekten Dickeya og Pectobacterium. Disse er noe ulike med hensyn på geografisk distribusjon, foretrukket temperatur for vekst og sykdomsspredning (virulens), typisk vertsspekter, i tillegg til hvilke sykdomssymptomer de gir. De likevel næres alle av vertens råtne vev, som de bløter opp ved å skille ut en rekke plantecelleveggdegraderende enzymer i det intercellulære rommet. Dette arbeidet har undersøkt flere aspekt ved bløtråtebakteriers biologi og virulens. Målet har vært å bidra til forbedring av settepotetenes helse. For å få bedre innsikt i taksonomi og fylogeni av disse bakteriene, har genomene blitt sekvensert av to isolat som virket atypiske i tidligere fylogenetiske analyser. Dette førte til beskrivelse av den nye arten Pectobacterium polaris, som etterpå ble funnet igjen i eldre samlinger av isolat i Polen og Nederland. Identifiseringen av denne nye arten kan føre til forbedrede deteksjonsmetoder, som igjen kan gjøre det lettere å tilrettelegge for tilpassede bekjempelsesstrategier. En treårig feltstudie ble også gjennomført, der helsen til norske settepoteter av ulike sorter og varierende kvalitet ble vurdert. Dette ble gjort for å undersøke faktorer knyttet til potetsorter og miljø, i tillegg til å teste implementeringen av storskala molekylær testing av utbredelsen av bløtråtebakterier. Undersøkelsen viste at bløtråtebakterier var nesten allestedsnærværende, uavhengig av potetsort og kvalitet. Et unntak var knoller av høyeste kvalitet. Disse knollene testet nokså pålitelig lavt i infeksjonsutbredelse, og sammenlignet med i knoller av lavere kvalitet, var sykdom sjeldent observert. Klima, og særlig nedbør, spilte den viktigste rolle for infeksjonsutbredelse. Forekomst av stengelråte var delvis bestemt av potetsorten. Dette kom særlig fram i en sort (Innovator), som var minst mottakelig mot denne sykdommen. Den kom også best ut i en test, der 15 forskjellige sorter ble infisert med P. polaris og P. atrosepticum. I denne testen kom det også fram at temperatur var den faktoren som hadde størst effekt på utvikling av råten. Denne studien ga innsikt i helsestatusen til norske settepoteter med hensyn på bløtråte og viktige miljøfaktorer som påvirker sykdommen. I tillegg ble en toårig feltstudie gjennomført for å undersøke tilstedeværelse av bløtråtebakterier i insekter som ble fanget i potetåkrer. Insektene ble testet med qPCR, som gjorde det mulig å velge ut eksemplarer som inneholdt store mengder bakterier. Disse insektene ble identifisert med DNA-sekvensering, og viste seg å tilhøre over 90 ulike arter. I løpet av de to årene, inneholdt 15 og 20 % av de testede insektene store mengder av bløtråtebakterie, inkludert et felt der rene settepoteter ble dyrket. Dette er interessant fordi man ikke sikkert vet hvordan settepoteter blir først infisert. Bønneflue (Delia platura) var den arten som oftest bar med seg store mengder av bakterien. Den samme arten, og nært beslektede fluer, har i tidligere studier vist seg å overføre bakterien til poteter og andre planter. Det høye antallet insekter som var bærere av bløtråtebakterier og identifisering av kjente vektorarter, viste at insekter potensielt spiller en mye viktigere rolle i smitte av rene poteter enn først antatt. Transkriptomet av typestammen til P. polaris, i tillegg til en stamme av P. carotovorum subsp. carotovorum, ble analysert under infeksjon av potetknoller ved hjelp av RNA-sekvensering. Dette ble gjort for å undersøke regulering av virulensfaktorer i bakterien i ulike utviklingsstadier av sykdommen. I begge de undersøkte stammene ble viktige virulensgener, som f.eks. koder for enzymer som bryter ned vertens cellevegg, i tillegg til flere bakterielle sekresjonssystemer, redusert i uttrykk over tid. Dette indikerte et skifte i de prioriterte funksjonene i den undersøkte bakterien. Bedre forståelse av de molekylære prosessene og framdrift av infeksjonen, kan hjelpe med å utvikle og optimalisere bekjempelsesstrategier.
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- 2018
16. Soft Rot Enterobacteriaceae Are Carried by a Large Range of Insect Species in Potato Fields
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Rossmann, Simeon, primary, Dees, Merete Wiken, additional, Perminow, Juliana, additional, Meadow, Richard, additional, and Brurberg, May Bente, additional
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- 2018
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17. Pectobacterium polaris sp. nov., isolated from potato (Solanum tuberosum)
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Dees, Merete Wiken, primary, Lysøe, Erik, additional, Rossmann, Simeon, additional, Perminow, Juliana, additional, and Brurberg, May Bente, additional
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- 2017
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18. Genomic signatures and insights into host niche adaptation of the entomopathogenic fungus Metarhizium humberi.
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Iwanicki, Natasha Sant0Anna, Riguetti Zanardo Botelho, Ana Beatriz, Klingen, Ingeborg, Júnior, Italo Delalibera, Rossmann, Simeon, and Lysøe, Erik
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BIOLOGICAL control of agricultural pests , *ENTOMOPATHOGENIC fungi , *METARHIZIUM , *AMINO acid transport , *SUGARCANE , *POLYKETIDE synthases , *MEDICAGO - Abstract
The genus Metarhizium is composed of species used in biological control programs of agricultural pests worldwide. This genus includes common fungal pathogen of many insects and mites and endophytes that can increase plant growth. Metarhizium humberi was recently described as a new species. This species is highly virulent against some insect pests and promotes growth in sugarcane, strawberry, and soybean crops. In this study, we sequenced the genome of M. humberi, isolate ESALQ1638, and performed a functional analysis to determine its genomic signatures and highlight the genes and biological processes associated with its lifestyle. The genome annotation predicted 10633 genes in M. humberi, of which 92.0% are assigned putative functions, and )17% of the genome was annotated as repetitive sequences. We found that 18.5% of the M. humberi genome is similar to experimentally validated proteins associated with pathogen–host interaction. Compared to the genomes of eight Metarhizium species, the M. humberi ESALQ1638 genome revealed some unique traits that stood out, e.g., more genes functionally annotated as polyketide synthases (PKSs), overrepresended GO-terms associated to transport of ions, organic and amino acid, a higher percentage of repetitive elements, and higher levels of RIP-induced point mutations. The M. humberi genome will serve as a resource for promoting studies on genome structure and evolution that can contribute to research on biological control and plant biostimulation. Thus, the genomic data supported the broad host range of this species within the generalist PARB clade and suggested that M. humberi ESALQ1638 might be particularly good at producing secondary metabolites and might be more efficient in transporting amino acids and organic compounds. [ABSTRACT FROM AUTHOR]
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- 2022
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19. Investigating possible biotic causes of poor potato emergence by DNA metabarcoding and morphological nematode analysis : a case study
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Løwø, Sunniva, Brurberg, May Bente, Rossmann, Simeon, Tangvik, Marte, and Haukeland, Solveig
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Forsinket spiring hos potetplanter, og redusert avling og kvalitet ble observert på betydelige arealer i flere potetåkere på Engeløya i Nordland i 2018 og 2019. Ingen åpenbar årsak ble funnet. Det ble tatt jordprøver i områdene med normal og forsinket vekst, og i overgangen mellom disse i tre åkere i 2020 og 2021. DNA-metastrekkoding ble gjennomført for å kartlegge bakterier, sopp, oomyceter og nematoder. Jordprøvene ble også analysert for planteparasittære nematoder, inkludert cyster, for å sammenligne DNA-metastrekkoding med tradisjonelle metoder. Videre ble nematoder ekstrahert fra potetknoller med symptomer på Streptomyces spp. (flatskurv), da man har sett at Pratylenchus spp. kan gi lignende symptomer på knollene. Nematodene ble ekstrahert og identifisert morfologisk. Den vanligste planteparasittære nematoden i jordprøvene var rotsårnematoden Pratylenchus crenatus. Amplikonsvekvensvarianter (ASVer) karakterisert som Pratylenchus spp. var også mest abundant blant planteparasittære nematoder i metastrekkodeanalysen. Det ble ikke funnet Pratylenchus spp. i potetprøver med flatskurvsymptomer. ASVer tilordnet Paratrichodorus spp. ble observert oftere i områder med forsinket vekst enn i områder med god vekst, men denne slekta ble ikke funnet i nematodeekstraksjonen. Potetcystenematoder (Globodera rostochiensis og G. pallida), som er nematodekandidater ved dårlig vekst, ble ikke funnet. I en av åkrene ble det funnet Rhizoctonia spp. i områder med forsinket vekst. Rhizoctonia spp. kan inngå i sykdomskomplekser med frittlevende nematoder. I denne åkeren ble det også funnet P. crenatus, men antallet nematoder, som varierte fra 87-116 individer per 250 mL jord, er trolig under skadeterskel for denne arten. Oomyceten Globisporangium irregulare var vanligere i områder med forsinket vekst enn i områder med god vekst på alle åkrene. G. irregulare har et bredt vertsspekter og kan gi dårlig spiring i en rekke vertsplanter, men den er ikke kjent for å gjøre skade i potet. ASVer tilordnet Aphanomyces spp. var vanlig på alle skiftene. Plantepatogene Aphanomyces-arter kan gi rotråte i belgfrukter og noen andre arter, men det er ikke kjent at den gjør skade i potet. En tydelig årsak til den forsinkede spiringen i potetåkrene har ikke blitt funnet, men det ble funnet flere faktorer som kan ha ført til forsinket vekst. For å fastslå årsaken behøves det videre undersøkelser, inkludert isolering av skadegjørere og smitteforsøk. Delayed emergence of potato plants and reduced yield and quality were observed in large areas of several potato fields in Engeløya, 150 km north of the Arctic circle in Norway, in 2018-2019. Since no obvious cause was found, soil samples were collected in zones showing normal and delayed growth, and in the transition zones between these, in three fields in 2020 and 2021. DNA metabarcoding was performed to identify present bacteria, fungi, oomycetes, and nematodes. Soil samples were also analyzed for plant-parasitic nematodes, including cysts, to compare DNA metabarcoding with traditional methods. Furthermore, nematodes were extracted from potato tubers showing symptoms of Streptomyces spp. (common scab), as Pratylenchus spp. have been shown to cause similar symptoms on tubers. The extracted nematodes were counted and identified morphologically. The most prevalent plant-parasitic nematode in the soil samples was the root lesion nematode Pratylenchus crenatus. Amplicon sequence variants (ASVs) designated Pratylenchus spp. were also the most abundant among plant-parasitic nematodes in the metabarcoding analysis. However, no Pratylenchus spp. were detected in potato tuber samples showing common scab symptoms. ASVs designated Paratrichodorus spp. were more common in areas with delayed growth than in areas with good growth, however, this genus was not detected in the nematode extractions. Potato cyst nematodes (Globodera rostochiensis and G. pallida), which are obvious nematode candidates of poor growth, were not detected. In one field, Rhizoctonia spp. was present in the parts of the field with poor growth. In this same field P. crenatus was also detected, but the number of nematodes ranged from 87-116 individuals per 250 mL soil, which is likely below the expected damage threshold for this species. Rhizoctonia spp. and free-living nematodes have been found to join in disease complexes. The oomycete Globisporangium irregulare was more prevalent in the poor-growing parts across all fields. G. irregulare has a broad host range and is known to cause damping off disease in many plants, however, it is not described as a potato pathogen. ASVs designated Aphanomyces spp. were common in all three fields. Plant-pathogenic Aphanomyces species are known to cause root rot in legumes, and a few other species, but not in potato. A single cause of the delayed emergence in the potato fields has not been shown, but several factors that are associated with delayed growth were found. To narrow down the cause further, additional studies are needed, including isolation of potential pathogens and infection trials. M-PV
- Published
- 2022
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