Temporal changes in the population structure ofDothistroma septosporumat the site of the first recorded outbreak in Poland

Abstract

In this study, evolution of the genetic structure of the oldest known population of Dothistroma septosporum in Poland was analysed. Dothistroma needle blight was first recorded in Poland in 1990 in a 5‐year‐old plantation, meaning the population is relatively young in terms of evolution and genetic development. The preservation of DNA extracts from other studies allowed examination of the genetic variation of the pathogen over the span of a decade with the use of highly sensitive microsatellite markers. A number of evolutionary factors were identified that have shaped the genetic structure of this population over time. First, indications of the founder effect and the impact of selection were observed. Secondly, structure analysis provided evidence of the introduction of a new genetic component to the population structure after the pathogen had established. Finally, the impact of the reproductive mode on various components of the Domiarki population was examined, revealing the presence of genetic groups and structure clusters with varying levels of sexual recombination. These results demonstrate how well established and genetically robust a new population of a pathogen may become in just a few decades, given favourable conditions, and how new introductions may facilitate this process.

Worldwide Genetic Structure Elucidates the Eurasian Origin and Invasion Pathways of Dothistroma septosporum, Causal Agent of Dothistroma Needle Blight

“…Individual population studies have shown unexpected levels of diversity in many populations [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. This diversity indicates that sexual reproduction is more common than previously thought, particularly as the sexual stage (previously known as Mycosphaerella pini ) has only rarely been observed, and the asexual stage is ubiquitous.…”

Occurrence of Dothistroma needle blight in Lithuania and Belarus: The risk posed to native Scots Pine forests

“…Many authors suggest that the equal presence of both mating types and the high genetic diversity of European D. septosporum populations increases the likelihood of sexual reproduction of the fungus and genetic recombination (Adamson et al., 2018; Barnes et al., 2008; Boron et al, 2019; Drenkhan et al., 2013; Groenewald et al, 2007; Mullett, Brown, & Barnes, 2015), as well as increases the possibility of the pathogen to co‐evolve with the native pine hosts (Barnes et al., 2011, 2014; Boroń et al, 2016; Drenkhan et al., 2014, 2016; Kowalski & Jankowiak, 1998; McDonald & Linde, 2002; Perry, Brown, Cavers, Cottrell, & Ennos, 2016; Perry, Wachowiak, et al, 2016; Piotrowska et al., 2017). Recent studies in the UK have shown a high variability in the aggressiveness of the pathogen and in the susceptibility of Scots pine populations to D. septosporum , including the different adaptive capacity of trees to survive and co‐exist with the pathogen (Fraser et al., 2015; Perry, Brown, et al, 2016).…”

“…During the last decades, the DNB disease has significantly increased in intensity and severity across Europe and worldwide (Adamson, 2018; Boron et al., 2019; Brown & Webber, 2008; Drenkhan et al., 2016; Kranjec‐Orlović et al., 2019; Woods et al., 2016). In eastern and northern parts of Europe, only D. septosporum is found on native host Pinus sylvestris L. (Adamson et al., 2018; Barnes et al., 2008; Drenkhan, Hantula, Vuorinen, Jankovský, & Müller, 2013; Drenkhan et al., 2016; Fraser, Brown, & Woodward, 2015; Millberg, Hopkins, Boberg, Davydenko, & Stenlid, 2016; Müller, Hantula, & Vuorinen, 2009; Mullett et al, 2018; Solheim, 2012; Solheim & Vuorinen, 2011).…”

“…However, the origin of the fungus remains unclear. Recent genetic studies have shown that the most genetically diverse populations of D. septosporum were found in northern and eastern Europe, indicating that the fungus may be endemic in Europe and that Scots pine forests in this region may represent the natural range of D. septosporum (Adamson et al., 2018; Barnes, Wingfield, Carbone, Kirisits, & Wingfield, 2014; Boron et al., 2019; Drenkhan et al., 2013; Ennos, Sjökvist, Piotrowska, Riddell, & Hoebe, 2020; Mullett, Brown, Fraser, Baden, & Tubby, 2017; Piotrowska et al., 2017).…”

“…(Markovskaja & Raitelaitytė, 2016; Raitelaitytė et al., 2016). Comprehensive studies have shown that only D. septosporum is spreading in Lithuania and neighbouring countries (Poland, Latvia and Estonia) on P. sylvestris in natural stands and plantations (Adamson et al., 2018; Boroń, Lenart‐Boroń, & Mullett, 2016; Boron et al., 2019; Drenkhan, Adamson, Jürimaa, & Hanso, 2014; Drenkhan et al., 2013, 2016; Kowalski & Jankowiak, 1998). In Europe, D. pini and D. septosporum in the same stand and on the same P. sylvestris host were found only in Slovenia (Piškur, Hauptman, & Jurc, 2013), Montenegro (Lazarević, Davydenko, & Millberg, 2017) and Slovakia (Jánošíková‐Hečková et al., 2018).…”