Vol 57, No 1 (2023)

The paper is devoted to ecological and biodiversity studies on basidiomycetes associated with common juniper (Juniperus communis) from subtaiga zone of Belarus as well as several taiga regions of the European part of Russia, namely, the Leningrad Region, the Republic of Karelia, the Komi Republic, the Arkhangelsk Region, the Murmansk Region. The taiga zone represents an ecological-coenotic optimum of common juniper and the widest spectrum of its fungal consorts is expected to be revealed. A total of 96 species of wood-inhabiting basidiomycetes, both from dead and living wood, were recorded in association with J. communis in the boreal regions of Belarus and the European part of Russia. These species belong to the Pucciniomycetes (Pucciniales, 3 species), Dacrymycetes (Dacrymycetales, 1 species), and Agaricomycetes (Agaricales, Atheliales, Auriculariales, Boletales, Cantharellales, Gloeophyllales, Gomphales, Hymenochaetales, Polyporales, Russulales, Thelephorales, Trechisporales, 92 species). An annotated species list is given, including an expanded substratum and ecology datasets. The ecological and geographical preferences of these fungi and the strength of their connection with juniper were analyzed by thermal map, clusterization, and Sankey diagram methods. The various types of wood decomposition by juniper-associated basidiomycetes were discussed. The global distribution pattern of the species was analyzed. It was concluded that the biota of basidiomycetes associated with juniper in Eastern European taiga forests is a heterogeneous and heterochronous formation, where it is possible to distinguish clearly a florogenetically ancient core of the species specialized on juniper, exhibiting in one or other way biotrophic properties, and several taiga sets of species (suites) connected with pine trees and their litter as well as with spruce-pine-leaved taiga mosaics and boreo-nemoral mosaics typical of the Northern Hemisphere.

A total of 11 strains ascomycetes-destructors of technical nonylphenol (NP) and 4-tert-octylphenol (4-t-OP) were isolated from nonylphenol-contaminated soddy-podzolic loamy soil (Leningrad Region, Russia). Fungal isolates are able to degrade NP and 4-t-OP at a high load (300 mg/L). The most effective Fusarium solani 8F strain has the ability to degrade alkylphenols (AP) both under cometabolic conditions and without additional carbon and energy sources. The decrease in AP is due to the processes of biodegradation and/or biotransformation by the studied strain and, to a small extent, due to sorption by fungal cells. The NP and 4-t-OP half-life under cometabolic conditions is 3.5 and 6.4 hours, respectively, and without additional carbon and energy sources, 9 and 19.7 hours, respectively. The amount of the lipid peroxidation product, malondialdehyde, as well as the reduced glutathione content in the process of NP and 4-t-OP biodegradation under cometabolic conditions increases by 1.7 and 2 times, respectively, compared with the control. The high level of reduced glutathione in F. solani 8F cells may indicate the participation of this metabolite both in the processes of AP biodegradation and in providing strain resistance to oxidative stress. To our knowledge, this is the first report on the degradation of NP and 4-t-OP by ascomycetous fungus F. solani both under cometabolic conditions and without additional carbon and energy sources. The revealed high potential of soil ascomycetes to degrade alkylphenols can be the basis for new environmentally safe bioremediation technologies for the purification of endocrine-disruptors conta-minated soils, natural and waste waters.

Barley net blotch is an economically important disease. The causative agent is an ascomycete, Pyrenophora teres, which exists in two forms: P. teres f. teres (Ptt) and P. teres f. maculata (Ptm), which differ in their symptoms on barley plants. These two forms are easily crossed in laboratory conditions with the formation of fertile offspring, however, it is extremely difficult to prove the hybrid nature of fungal isolates, sometimes found in natural populations of the pathogen and bearing signs of both forms. In 2020, we first identified Ptt × Ptm hybrids in natural populations of P. teres in Krasnodar Region in isolates collected in 2016. The aim of the studies was to compare the virulence of two Ptt isolates, two Ptm isolates of different origin and a hybrid isolate Ptt × Ptm to a wide set of barley genotypes from the VIR collection pre-selected for Ptt resistance, to determine variability of the virulence trait in the hybrid isolate and characterize resistance to both forms of the fungus and hybrid. Depending on the barley genotype, 3 types of disease symptoms were manifested upon inoculation with the Ptt × Ptm hybrid isolate: (1) similar to Ptt, (2) similar to Ptm, and (3) a mixed type. Apparently, the manifestation of symptoms after inoculation with the hybrid isolate depends on the barley genotype influencing the expression of certain pathogen effector genes. It was shown that in most cases Ptm isolates differ in virulence from Ptt isolates to the same barley genotypes, and the Ptt × Ptm hybrid isolate from both Ptt and Ptm. On average, the Ptt × Ptm hybrid isolate was less aggressive than the Ptt and Ptm isolates. A comparison of the types of responses of barley genotypes to all studied isolates of Ptt and Ptm revealed 8.8% of genotypes resistant to both forms of P. teres and 5.6% to Ptt, Ptm and the hybrid isolate Ptt × Ptm. The virulence of natural hybrid between two forms of P. teres Ptt × Ptm was studied for the first time. The barley genotypes resistant to the two forms of the net blotch are valuable source of resistance for barley breeding.