Mycology and Phytopathology

The review highlights the situation with the development of resistance to various systemic fungicides in Venturia inaequalis around the world and in Russia, with an assessment of the prospects for their further use. Information is provided on all fungicides used in Russia against apple scab, their effectiveness at a given time, and a description of each chemical class. Data on the mechanisms of resistance to chemicals in the pathogen, including at the molecular level, are presented. The problem of the development of resistance in V. inaequalis and possible ways of its solution at the present level of scientific knowledge are discussed.

Ecological and taxonomic study of mycobiota of cultivated plants and native flora, including endemic ones, from phylogenetic systematics’ perspective, remains one of the interesting topics of microbial ecology. The structure of yeast communities of endemic to the Caucasus Georgian honeysuckle in comparison with grapes, a traditional agricultural crop of the republic, has been studied in the territory of Dagestan. The yeast complex of grapes was studied in ampelocoenoses located on the plain and in the foothills, and in shrubs of Georgian honeysuckle also on the plain and in the mountains. The number of yeasts (per unit of weight) on the plants is higher than in soils, with the highest number of yeasts found on leaves. Grape and honeysuckle berries’ surfaces contain more yeasts than leaves. The influence of grape cultivars on the species diversity and abundance of yeasts was observed, as well as a tendency for their abundance to decrease with increasing altitude. On the contrary, Georgian honeysuckle growing in the mountains and the soil under it was colonized by yeasts more than on the plain. Its species structure included five species, two of which — Aureobasidium pullulans and Metschnikowia pulcherrima — are also typical for ampelocoenosis. Yeast population of plant endemic on the plain was notable for specificity, one of two isolated species was found and identified for the first time as a new species of the genus Zygotorulaspora — Z. dagestanica, associated with leaves and soil, where they dominate being 79.2% of the total yeast number. Despite the close climatic conditions of sites with wild plants and grapes in the plain, their taxonomic composition differed significantly and included two and nine species, respectively. The results obtained show the perspective of studying yeast communities of endemic plants.

The article reports the results of macrofungi surveys in the planned protected area Lake Nyuk (pPA), situated in the north-west of the Republic of Karelia. The forests there are primarily north-boreal pine stands with pine trees aged 170—250 years at maximum. As of now, records from the pPA include 183 species of 114 genera of aphyllophoroid and agaricoid fungi. The annotation for each species specifies their habitats and occurrence. Seven species are reported for the biogeographical province Karelia pomorica occidentalis for the first time; of which two species, Hydnellum gracilipes and Tubulicrinis medius, are first records for the Republic of Karelia. The territory was found to harbor nine fungal species (Anthoporia albobrunnea, Diplomitoporus crustulinus, Flavidoporia mellita, Gloeophyllum protractum, Resinoporia crassa, Rhodonia placenta, Sidera lenis, Skeletocutis sajanensis, S. stellae) red-listed in the Republic of Karelia (2020). Locations of 13 indicator species and 16 specialist species of biologically valuable forests are known within the pPA. The findings are validated by the herbarium specimens stored at the Karelian Research Centre RAS Herbarium (PTZ) and Botanical Museum of the University of Helsinki (H). The rationale for establishing a nature conservation area in the territory is provided.

The submicron particles effect of heavy metal oxides WO₃, CsTeMoO₆ и RbTe_1.5W_0.5O₆ with photocatalytic activity on the content of hydrogen peroxide and the activity of extracellular oxidoreductases (catalase, peroxidase) in the cultivation medium of the Aspergillus niger and Penicillium chrysogenum fungi was studied. Addition of the studied compounds to the cultivation medium reduced the H₂O₂ content for both fungi. An ambiguous effect of the studied compounds on the activity of extracellular catalase and peroxidase was noted. In most cases, these compounds caused an increase in the activity of the studied enzymes both under light and in the dark. A significant decrease in activity was shown only for exocatalases of both fungi under the influence of WO₃ and under the influence of CsTeMoO₆ in P. chrysogenum.

Ascochyta leaf blight of soybean is a widespread disease caused by several closely related Phoma-like species, this disease often leads to significant crop losses. Among Phoma-like species from Didymellaceae family, the most frequently associated with symptomatic soybean tissues are species of the genera Boeremia and Didymella. Currently reliable species identification in Didymellaceae relies on polyphasic approach based on consolidated species concept and combined molecular phylogenetic, micromorphological and cultural features. At least three loci are commonly used for reconstruction of the molecular phylogeny of Didymellaceae: internal transcribed spacer (ITS) of the ribosomal DNA, partial RNA-polymerase II gene (rpb2), and β-tubulin (tub2). As a result of long-term phytosanitary monitoring of soybean crops, soybean leaves with symptoms of Ascochyta blight were collected from major soybean producing areas of Russia. From surface sterilized plant tissues more than 100 isolates of Phoma-like fungi were obtained and stored in the collection of pure cultures of the Laboratory of Mycology and Phytopathology (MF, All-Russian Institute of Plant Protection). Most of them, as a result of multilocus phylogenetic analysis, were identified as Boeremia and Didymella species. Eight isolates were identified as species of other genera, suspected to be rare findings. The aim of this study was to identify these eight isolates based on multilocus phylogenetic analysis, as well micromorphological, cultural, and pathogenicity data. Multilocus phylogenetic analysis has resulted in identification of all eight isolates to species level. Single isolate from the Ryazan region was Neoascochyta graminicola. Three other from three different districts of the Amur region were Remotididymella capsici. Two isolates from the Primorskiy territory and Amur region were Stagonosporopsis heliopsidis. Another two from two districts of the Amur region were S. stuijvenbergii. Pathogenicity tests have resulted in conclusion, that all studied isolates were not pathogenic for soybean leaves. Probably, these Phoma-like species are associate with soybean as saprophytes or endophytes. For all these Phoma-like species Glycine max was detected as substrate for the first time. Neoascochyta graminicola is widespread in Europe in association with Poaceae plants. There are only two findings of Remotididymella capsici in the world, both from leaves of Capsicum annuum. First finding was made in the former USSR in 1977 and was identified based on only morphological features. Second findings was collected in the Fiji and verified with multilocus phylogenetic analysis. Stagonosporopsis heliopsidis isolates were revealed in the USA, Canada, Netherlands and Russia and this fungus was believed to be specific for Asteraceae plants. Isolates of Stagonosporopsis stuijvenbergii are known only from soil in the Netherlands. Thus, such species as Neoascochyta graminicola and Stagonosporopsis stuijvenbergii were revealed in the Russia for the first time. Studied Remotididymella capsici isolates were first confirmed findings of this fungus in Russia. Additionally to detailed phylogenetic data, the manuscript is supplement with a detailed description of the cultural and micromorphological features of all species.