Wojciech Szewczyk

Phylogenetic relationships among Porodaedalea pini from Poland and related Porodaedalea species

Porodaedalea pini has been found to be a pathogen of Pinus banksiana (1 specimen) and Pinus sylvestris (39 specimens) in north-western Poland. This fungus was initially identified by its host preferences and morphological characters of sporophores and basidiospores. The ITS 1/2 rDNA region was sequenced and analysed using the neighbor-joining, maximum likelihood and maximum parsimony methods. All P. pini from Poland, P. pini neotype and other P. pini isolates from Europe grouped together forming a moderately supported monophyletic clade. The clade included two groups which did not correlate with geographic ranges. Nucleotide polymorphism of the Polish isolates of P. pini was small. This study provides evidence for the taxonomy of some isolates of the Porodaedalea Holarctic Group in North America: grouping with P. laricis or with P. gilbertsonii suggests that the isolates belong to these species. The absence of P. pini (in a form recognized in Europe) in North America is suggested. Sequencing of the ITS 1/2 rDNA region with the basidiomycete-specific primers (ITS1-F and ITS4-B) proved to be a suitable and sufficient method for differentiation of species within the genus Porodaedalea.

Assessment of leaf damage in oak stands in the flood-affected Wołów Forest Division

Abstract This study examines the effect of flood on oak stands in the Wołów Forest Division by assessing the loss of leaf area due to insect feeding as determined in laboratory analyses of samples collected from standing trees. We compared stands, in which water stagnated for at least one month and stands with no water stagnation. It was found that the mean damage to the carbon assimilating organs of stands with stagnating water was lowered by approximately 6% compared to stands that were not affected by flood. Thus, no definite effect of flood contributing to losses of carbon assimilating organs in oak trees could be shown.

Populations of Armillaria species in pine plantations in west-central Poland

Two diploid isolates of Armillaria gallica and 143 diploid isolates of A. solidipes were obtained from 145 samples of rhizomorphs, fruit bodies and infected wood of sessile oak and Scots pines from 5–10-year-old Scots pine plantations in three Forest Districts located 100–350 km apart in west-central Poland. Based on pairings among the 145 isolates, 18 somatic compatibility groups (genets) of A. solidipes were distinguished in the three plantations. Sequencing of ITS1/2 rDNA of 18 isolates representing the 18 genets delineated four nuclear haplotypes. This suggests that many of the A. solidipes genets are closely related and were possibly established by sib-related basidiospores. With a few exceptions there was general geographical specialization of genets but not haplotypes. Geographical specialization of genets and the dominance of single haplotypes suggest that the A. solidipes population results from clonal rather than sexual reproduction. Sequencing of the ITS1/2 and IGS-1 rDNA showed small nucleotide diversity in ITS1/2 rDNA and much more diversity in IGS-1 rDNA of the isolates of A. solidipes studied. However, none of these regions has sufficient resolution for the clear differentiation of A. solidipes from A. borealis. The sequences of the EF 1-alpha gene showed high interspecific variability in Armillaria species and very low intraspecific variability in A. solidipes. This gene is the most appropriate for reliable identification of biological species and subgroups of Armillaria. Its application is the most useful in ecological and epidemiological studies of