Genetic diversity of Lophodermium piceae in South Finland

Abstract

Lophodermium piceae, the dominant needle endophyte of Norway spruce (Picea abies), is known to be extremely diverse. This work aimed to test the possible occurrence of cryptic species within the morphological species L. piceae. Genetic variation in 36 South Finnish L. piceae isolates originating from six localities was investigated by comparing DNA sequences of three genetic markers. One of the markers was the internal transcribed sequence (ITS) of the ribosomal DNA and the other two (LP1 and LP2) were based on sequence characterized amplified regions designed for L. piceae. The LP2 marker could be detected only from isolates of L. piceae but not from 20 other ascomycete species tested. This sequence, therefore, is considered as a species-specific marker for L. piceae. For comparison, ITS sequences of isolates representing two other Lophodermium species, L. pinastri and L. seditiosum, were also investigated. In a neighbor-joining analysis of ITS sequences all L. piceae isolates fell into one cluster, which was clearly separate from those of L. pinastri and L. seditiosum. Dendrograms of the three markers were incongruent indicating that the L. piceae population examined consisted of a single phylogenetic species. No geographical differentiation was observed. Our results confirm that L. piceae is a genetically highly diverse endophytic species.

Analysis of fungal endophytes in Scottish Sitka spruce plantations shows extensive infections, novel host partners and gives insights into origins

“…The phylogenetic analysis of the ITS sequence data of Lophodermium species in Figure 4 shows that the isolates in this study cluster in a clade containing Stefani & Bérubé, 2006) strains. Whereas L. piceae is considered a species complex in North America (Stefani & Bérubé, 2006), in Europe, genetic analysis has been unable to demonstrate this (Müller et al, 2007), possibly due to the lower diversity of Picea species in Europe. Whereas L. piceae is considered a species complex in North America (Stefani & Bérubé, 2006), in Europe, genetic analysis has been unable to demonstrate this (Müller et al, 2007), possibly due to the lower diversity of Picea species in Europe.…”

“…In order to assess possible origins of Scottish L. piceae, a phylogenetic analysis with n = 96 taxa and Cenococcum geophilum (AM084698) as the outgroup taxon was conducted. In this analysis, L. piceae sequences were used from pine-hosted Lophodermium species in Scotland (Reignoux, Green, & Ennos, 2014), spruce-hosted species in North America (Stefani & Bérubé, 2006), and spruce-hosted species in Europe (Müller et al, 2007). Second, 34 taxa including other members of Capnodiales with Venturia inaequalis HIR 2 (the outgroup taxon) were used for putting the unknown endophyte in context.…”

“…Lophodermium piceae is a commonly isolated endophyte in spruce forests and plantations (Barklund, 1987;Fan et al, 2012;Koukol et al, 2012;Magan & Smith, 1996;Müller & Hallaksela, 1998;Müller et al, 2007;Sieber, 1988;Solheim, 1994;Stefani & Bérubé, 2006) and has a very wide distribution. The phylogenetic analysis of the ITS sequence data of Lophodermium species in Figure 4 shows that the isolates in this study cluster in a clade containing North America-to-Europe direct spore dispersal has been shown to occur in some pathogenic endophyte populations and probably occurs on a large scale with a multitude of different fungal spores (Brown & Hovmøller, 2002;Stefani & Bérubé, 2006).…”

“…Lophodermium piceae is a cosmopolitan endophyte once thought to be a problematic pathogen of spruce (Gregory & Redfern, 1987), but now considered a weak pathogen at worst, as studies fail to find a strong correlation between poor growth and infection. Both of these species are commonly recorded as endophytes (in their quiescent and saprophytic stages) of the European native Picea abies (Norway spruce), but both have also been recorded on other North American Picea species (Butin, 1986;Carroll & Carroll, 1978;Johnson & Whitney, 1992;Korkama-Rajala, Müller, & Pennanen, 2008;Koukol, Kolařík, Kolářová, & Baldrian, 2012;Lehtijärvi & Barklund, 2000;Livsey & Barklund, 1992;Magan & Smith, 1996;Müller & Hallaksela, 1998Müller, Valjakka, & Hantula, 2007;Müller, Valjakka, Suokko, & Hantula, 2001;Nguyen, Boberg, Ihrmark, Stenström, & Stenlid, 2016;Scattolin & Montecchio, 2009;Sieber, 1989;Stefani & Bérubé, 2006;Suske & Acker, 1989). However, its virulence appears to be variable depending on several factors such as host, host age and climactic factors (Diamandis, 1978;Diamandis & Minter, 1980;Juzwik, 1993;Scattolin & Montecchio, 2009).…”

A better understanding of functional roles of fungi in the decomposition process: using precursor rRNA containing ITS regions as a marker for the active fungal community

“…It is amplifiable by RT-PCR directly from environmental samples (Anderson and Parkin 2007;Bastias et al 2007;Rajala et al 2011;Baldrian et al 2012), and it also provides good resolution for fungal taxonomy via BLAST searches at the genera or species level (Anderson and Parkin 2007). However, some cases of intraspecific variation have been reported (Müller et al 2007) and for fungal taxa, it is too variable to allow reliable multiple sequence alignment and subsequent phylogenetic placement and OTU delimitation. Other than rRNA, some specific types of biochemical markers have been used for quantification of fungal biomass and/or fungal activity, for example certain types of fatty acids in the neutral lipid and phospholipid fatty acid fractions as well as ergosterol content.…”