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3. Doktoritööd

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/7081

Sirvi

Sirvi 3. Doktoritööd Autor "Adamson, Kalev" järgi

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  • Pisipilt
    Kirje
    Distribution and population genetic analysis of the agents of invasive needle and shoot diseases of conifers in Northern Europe
    (Eesti Maaülikool, 2017) Adamson, Kalev; Drenkhan, Rein; Capretti, Paolo (opponent)
    Generally, invasive pathogens settle first exotic host species and later the native ones. Invasive conifer pathogens Lecanosticta acicola and Diplodia sapinea were first documented in northern Europe on exotic hosts and later on native ones. Still, L. acicola has not been found on the native Scots pine. Abies species for the known as pine pathogen Dothistroma septosporum and Pinus mugo var. pumilio for L. acicola were documented as the new hosts for them. Quarantine pest L. acicola is thought to spread into and inside Estonia via anthropogenic activity. It was proved by the mating type analyses, as only MAT1-1 was firstly found and several years later MAT1-2 was detected. It predicts increasing virulence of the pathogen. Similarly has spread D. sapinea, the pathogen was documented first time on Austrian pine in one location and after that on Scots pine individuals in 2012 in Vormsi Island. At the same time the pathogen was naturally distributing from South to North as a clear front and has reached the northernmost front up to the central Estonia by 2014. Investigations demonstrated that exotic host species are more sensitive to alien pathogens than are native ones. Several analysed genetic characteristics of D. septosporum populations in northern Europe, in Russian Far East (eastern Asia) and Bhutan (south central Asia) revealed that the fungus is not alien in northern Europe, but may be native to Baltic countries, Finland and western Russia. This result confutes the hypotheses that D. septosporum could spread to northern Europe from eastern populations. Asian D. septosporum populations were not similar to the northern European ones, but the clustering analyses showed some similar genetic pattern in populations of the Russian Far East and west coast of Norway. Other analysed populations in northern Europe were quite similar. The annual forest survey (including molecular survey) discovers and provides valuable information about new invasive forest pathogens, their disease severity and host range. It is essential for assessment of current situation in forests and helps to outline quicker and effective protection measures. At the same time the thesis provides information to quarantine regulation authorities by early detecting the pathogens and evaluating their spread in our environment. We recommend to deal with the imported seedlings and seeds with special care, while they may carry new pathogens or new genes of the already known ones.