Diversity and ecology of Armillaria species in virgin forests in the Ukrainian Carpathians

Abstract

In this study, we investigated the diversity and ecology of Armillaria species in virgin pure beech and mixed conifer forests (15,000 ha) of the Carpathian Biosphere Reserve in Ukraine. Armillaria rhizomorphs were systematically sampled, both from the soil and from the root collar of trees (epiphytic), on 79 plots (25×20 m) of a 1.5×1.5 km grid. In both forest massifs, rhizomorphs were present in the majority of the soil samples, with an estimated dry weight of 512 kg/ha in the pure beech forests and 223 kg/ha in the mixed conifer forests. Similarly, in both forest massifs, most of the trees inspected had rhizomorphs at the root collar. Species identification based on DNA analyses showed that all five annulated European Armillaria species occur in these virgin forests, as previously observed in managed forests in central Europe. However, differences in the frequencies of the single species were observed. The predominance of the preferentially saprotrophic A. cepistipes and A. gallica (84 and 15% of the specimens, respectively) and the absence of significant pathogenic activity suggest that in these virgin forests Armillaria species are most likely to behave as saprotrophs. Forest management may increase the frequency of the pathogenic species A. ostoyae, which is rare in virgin forests.

Evaluation of partial tef1, rpb2, and nLSU sequences for identification of isolates representing Armillaria calvescens and Armillaria gallica from northeastern North America

“…This provides further evidence of the utility of the tef1 gene in accurately characterizing Armillaria species, a claim supported by previous studies (Maphosa et al 2006;Hasegawa et al 2010;Antonin et al 2009;Tsykun et al 2011). While not the focus of this study, this is important for distinguishing between A. solidipes and A. gemina, which produce fruiting bodies that cannot be distinguished morphologically (B erub e & Dessureault 1989), and have a very close genetic relationship to one another (Anderson & Stasovski 1992;Piercey-Normore et al 1998;Kim et al 2006).…”

“…While A. gallica was included in this study, A. calvescens was not. More recently, partial tef1 sequences were used by Hasegawa et al (2010) to successfully distinguish eight species of Armillaria from Japan, and by researchers in Eastern Europe to discriminate isolates in the A. gallica complex (Antonin et al 2009;Tsykun et al 2011). In addition to the tef1 gene, partial sequences from the RNA polymerase II (rpb2) gene have proven to be useful in discriminating closely-related species of basidiomycete fungi (Matheny et al 2007).…”

Transcriptome of an Armillaria root disease pathogen reveals candidate genes involved in host substrate utilization at the host–pathogen interface

“…; Tsykun et al. ). Currently recognized Armillaria species vary in virulence and host range (Brazee and Wick ; Hasegawa et al.…”

Comparative assessment of SSR and SNP markers for inferring the population genetic structure of the common fungus Armillaria cepistipes

“…Because of this high longevity and the stable territoriality, Armillaria may influence forest structure and dynamics over several generations of host trees. The preferentially saprophytic A. cepistipes is widely distributed in Europe and frequently occurs in mountain forests from the Alps to the Carpathians (Heinzelmann et al, 2012;Tsykun et al, 2012). Armillaria cepistipes spreads locally by producing a dense network of vegetative rhizomorphs in the soil, through which it can rapidly colonize new food bases (for example, fresh stumps or wood debris).…”