Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2024
Abstract
Phytophthora cactorum is a plant pathogenic oomycete that causes crown rot in strawberry leading to significant economic losses every year. To invade the host, P. cactorum secretes an arsenal of effectors that can manipulate host physiology and impair its defense system promoting infection. A transcriptome analysis was conducted on a susceptible wild strawberry genotype (Fragaria vesca) 48 hours post inoculation with P. cactorum to identify effectors expressed during the early infection stage. The analysis revealed 4,668 P. cactorum genes expressed during infection of F. vesca. A total of 539 secreted proteins encoded by transcripts were identified, including 120 carbohydrate-active enzymes, 40 RXLRs, 23 proteolytic enzymes, nine elicitins, seven cysteine rich proteins, seven necrosis inducing proteins and 216 hypothetical proteins with unknown function. Twenty of the 40 RXLR effector candidates were transiently expressed in Nicotiana benthamiana using agroinfiltration and five previously unreported RXLR effector genes (Pc741, Pc8318, Pc10890, Pc20813, and Pc22290) triggered cell death when transiently expressed. The identified cell death inducing RXLR effectors showed 31–66% identity to known RXLR effectors in different Phytophthora species having roles in pathogenicity including both activation and suppression of defense response in the host. Furthermore, homology analysis revealed that these cell death inducing RXLR effectors were highly conserved (82 - 100% identity) across 23 different strains of P. cactorum originating from apple or strawberry.
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Authors
Theresa Weigl Jorunn Børve Emily Follett Ingunn Øvsthus Carl Gunnar Fossdal Hanne Larsen Siv Fagertun RembergAbstract
https://ehc.usamv.ro/wp-content/uploads/2024/05/S10-Book-of-Abstracts.pdf The mid-early ripening cultivar, 'Summerred‘, is popular among consumers and widely grown in Norway. However, 'Summerred‘ fruit is prone to rapid softening and development of senescence-related disorders, especially senescent breakdown. Calcium can have a significant role in maintaining firmness and delaying senescence of fruits. In a two-year study, foliar application of calcium chloride (CaCl2) was conducted six times, with varying weather conditions between the growing seasons. Fruit was harvested at optimal commercial maturity and stored at 4 °C for either six or nine weeks, followed by simulated shelf-life conditions at 20 °C. Ethylene levels were monitored during storage to detect ripening discrepancies. At harvest, CaCl2-treated fruit exhibited significantly lower ethylene production compared to untreated fruit, although no differences were observed during the end of the storage period. Senescent breakdown showed significant variability between the two seasons, with an incidence of up to 15 % in the first season and nearly no incidence in the second season. Senescent breakdown increased with storage length but was not affected by foliar CaCl2 application. Real-time PCR analysis of fruit flesh samples revealed increased expression of polygalacturonase and β-galactosidases genes after storage, indicating their involvement in apple softening. Notably, there were no differences in gene expression between CaCl2-treated and untreated fruit after storage. Expression patterns of genes involved in ethylene biosynthesis at harvest were different between the two seasons. Higher expression was observed in the year when more disorder development occurred, indicating advanced maturity at harvest. There were no significant differences in Streif index between the two years.
Authors
Åsa Helena Frostegård Christer Magnusson Kjetil Klaveness Melby Nana Yaa Boahene Siamak Pour Yazdankhah Beatrix Alsanius Jorunn Børve Paal Krokene Mogens Nicolaisen Line Nybakken Johan A. Stenberg Iben Margrete Thomsen Sandra A.I. Wright May-Guri SæthreAbstract
Helse- og miljørisiko ved bruk av bakterien Psychrobacter sp. i plantevernmiddelet Nemaslug® Helserisikoen for mennesker ved bruk av Nemaslug® anses som lav, men man kan ikke utelukke risiko for svært infeksjonsutsatte pasientgrupper. Det er ingen bevis for helseproblemer som oppstår ved inntak av matvarer behandlet med Nemaslug®. Vitenskapskomiteen for mat og miljø (VKM) har, på oppdrag fra Mattilsynet, utført en risikovurdering av bakterien Psychrobacter sp. som inngår i plantevernmiddelet Nemaslug®. Plantevernmiddelet Nemaslug®, som er godkjent for bruk i Norge siden 2005, inneholder nematoden Phasmarhabditis hermaphrodita. Nematoden bærer en symbiotisk bakterie som fungerer som den aktive biokontrollorganismen ved å produsere giftstoffer som dreper snegler ved infeksjon. Bakgrunnen for oppdraget er at det ble avdekket at bakterien i Nemaslug® ikke er Moraxella osloensis, som den tidligere godkjenningen er basert på. Den er i stedet blitt identifisert som en art i bakterieslekten Psychrobacter, mest sannsynlig Psychrobacter faecalis, alternativt Psychrobacter pulmonis. Denne vurderingen skal danne grunnlag for Mattilsynets beslutning om hvorvidt Nemaslug® skal beholde sin godkjenning for bruk i Norge eller ei. Resultater Det er begrenset informasjon om helsefarene ved Psychrobacter sp. hos mennesker. Kunnskap om antibiotikaresistens og patogenisitet i slekten Psychrobacter er i stor grad mangelfull. Det er lite informasjon om forekomsten av Psychrobacter sp. i Norge. Potensialet for spredning og etablering av Psychrobacter sp. i miljøet under norske forhold vurderes som lavt. Risikoen Nemaslug® utgjør for ikke-målorganismer, spesielt bløtdyr, er usikker og krever videre forskning. Videre taksonomisk analyse og fullstendig genomsekvensering er nødvendig for å bekrefte artstilhørigheten til bakterien i Nemaslug®. Konklusjoner Selv om informasjonen om helsefarene knyttet til Psychrobacter sp. hos mennesker er begrenset, betraktes den generelt som et lavrisikopatogen. Helserisikoen for mennesker ved bruk av Nemaslug® anses derfor som lav, men risiko for pasientgrupper som er svært mottakelige for infeksjoner kan ikke utelukkes. Det er ingen bevis for helseproblemer som oppstår ved inntak av matvarer behandlet med Nemaslug®. Metode VKM har hentet data og informasjon fra søkeren via Mattilsynet og VKMs forrige rapport om Nemaslug®. Et grundig litteratursøk ble gjennomført for å innhente ytterligere relevant informasjon. Vurderingen er godkjent av VKMs faggruppe for plantehelse.
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