1. Diversity, migration routes, and worldwide population genetic structure of Lecanosticta acicola, the causal agent of brown spot needle blightMarili Laas, Kalev Adamson, Irene Barnes, Josef Janoušek, Martin S. Mullett, Katarína Adamčíková, Mitsuteru Akiba, Ludwig Beenken, Helena Bragança, Timur S. Bulgakov, Barbara Piškur, 2022, original scientific article Abstract: Lecanosticta acicola is a pine needle pathogen causing brown spot needle blight that results in premature needle shedding with considerable damage described in North America, Europe, and Asia. Microsatellite and mating type markers were used to study the population genetics, migration history, and reproduction mode of the pathogen, based on a collection of 650 isolates from 27 countries and 26 hosts across the range of L. acicola. The presence of L. acicola in Georgia was confirmed in this study. Migration analyses indicate there have been several introduction events from North America into Europe. However, some of the source populations still appear to remain unknown. The populations in Croatia and western Asia appear to originate from genetically similar populations in North America. Intercontinental movement of the pathogen was reflected in an identical haplotype occurring on two continents, in North America (Canada) and Europe (Germany). Several shared haplotypes between European populations further suggests more local pathogen movement between countries. Moreover, migration analyses indicate that the populations in northern Europe originate from more established populations in central Europe. Overall, the highest genetic diversity was observed in south-eastern USA. In Europe, the highest diversity was observed in France, where the presence of both known pathogen lineages was recorded. Less than half of the observed populations contained mating types in equal proportions. Although there is evidence of some sexual reproduction taking place, the pathogen spreads predominantly asexually and through anthropogenic activity.
Keywords: brown spot needle blight, Lecanosticta acicola, pones, Pinus spp., popularion structure
Published in DiRROS: 12.08.2022; Views: 570; Downloads: 284
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2. Biotic threats for 23 major non-native tree species in EuropeElisabeth Pötzelsberger, Martin M. Gossner, Ludwig Beenken, Anna Gazda, Michal Petr, Tiina Ylioja, Nicola La Porta, Dimitrios N. Avtzis, Elodie Bay, Maarten De Groot, Kristjan Jarni, Nikica Ogris, Marjana Westergren, 2021, original scientific article Abstract: For non-native tree species with an origin outside of Europe a detailed compilation of enemy species including the severity of their attack is lacking up to now. We collected information on native and non-native species attacking non-native trees, i.e. type, extent and time of first observation of damage for 23 important non-native trees in 27 European countries. Our database includes about 2300 synthesised attack records (synthesised per biotic threat, tree and country) from over 800 species. Insects (49%) and fungi (45%) are the main observed biotic threats, but also arachnids, bacteria including phytoplasmas, mammals, nematodes, plants and viruses have been recorded. This information will be valuable to identify patterns and drivers of attacks, and trees with a lower current health risk to be considered for planting. In addition, our database will provide a baseline to which future impacts on non-native tree species could be compared with and thus will allow to analyse temporal trends of impacts.
Published in DiRROS: 21.02.2022; Views: 609; Downloads: 683
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