European blueberry is a common plant in coniferous and mixed forests that grows in Russia, Northern Europe, Asia, United States, and Canada. Among the fungi that cause blueberry diseases, the most harmful are Diaporthe vaccinii and Colletotrichum acutatum. These fungi are included in the consolidated list of quarantine objects of the Eurasian Economic Union and their occurrence and spread in the territory of countries of this Union is subject to strict control. Most taxa of micromycetes, particularly, Diaporthe and Colletotrichum species, can be correctly identified to the species level based on solely molecular phylogenetic features. The aim of the present work was to assess the biodiversity of fungi associated with blueberry growing in North-Western Russia and in Finland using morphological and molecular genetic features. Altogether, the study included 17 specimens of wild blueberry exhibiting necrotic spots on leaves and stem lesions that were collected in 2017 in St. Petersburg and in five districts of Leningrad region, as well as in the Republic of Karelia and in Finland. Analysis of the morphological and molecular genetic features of the fungal strains isolated from these blueberry specimens led to identification of 11 species: Boeremia exigua, Colletotrichum salicis, Diaporthe eres, Fusarium avenaceum, F. incarnatum, F. sporotrichioides, Heterophoma sylvatica, Kalmusia longispora, Microsphaeropsis olivacea, Neocucurbitaria cava, and Sporocadus rosigena. There were also fungi representing two sections of the genus Alternaria: Alternaria and Infectoriae, and micromycetes of the genera Chaetomium, Cladosporium, Coniothyrium, Curvularia, Epicoccum, Penicillium, Pestalotiopsis, Sordaria, and Trichoderma. The species Colletotrichum salicis, Heterophoma sylvatica, Kalmusia longispora, Microsphaeropsis olivacea, and Neocucurbitaria cava were for the first time found in Russia. The species Sporocadus rosigena was for the first time detected in Finland. Fusarium avenaceum, F. incarnatum, and F. sporotrichioides were for the first time observed in association with blueberry plants. The species Diaporthe vaccinii and Colletotrichum acutatum included in the consolidated list of quarantine objects of the Eurasian Economic Union were not detected in this study.

—The genus Colletotrichum includes a number of plant pathogens of major importance, causing diseases in a broad variety of woody and herbaceous plants. Due to recent molecular analysis, Colletotrichum spp. have undergone many taxonomic changes, i.e., introduction of a significant number of new species and abolition of some old ones. The data on the species diversity, abundance and host specialization of species in this genus on the territory of Russia and neighboring countries are obviously far from being complete, do not correspond to the modern taxonomy of the genus and require substantial revision. In this work, the molecular genetic identification and pathogenicity assessment of 35 isolates, previously identified as Colletotrichum spp., from the European part of Russia, Ukraine, Siberia, and the Russian Far East were carried out. It has been found that 12 isolates obtained from wild plants and crops belong to the species Colletotrichum coccodes. The remaining isolates belong to destructivum (14 isolates) and dematium (9 isolates) species complexes. Among the members of the destructivum complex, it was possible to identify the species C. destructivum and C. lini. C. dematium, C. lineola and Colletotrichum cf. spinaciae were defined among the isolates of the dematium complex. Three isolates of C. destructivum from wild plants of Leningrad oblast and Kamchatka, to our knowledge, are the first findings of this species for Russia. According to the results of the pathogenicity assessment, three isolates assigned to the destructivum species complex may be of interest for the biocontrol of Galinsoga parviflora, and one isolate identified as С. coccodes may be potentially used for the control of Ambrosia artemisiifolia.

Альтернариозные пятнистости гуара

Didymellaceae is one of the largest families in the Pleosporales, encompassing main genera of Phoma-like fungi including Ascochyta, Didymella, and Stagonosporopsis and representing underestimated biodiversity. Plants in the Convolvulaceae often grow as weeds in many climates and host a wide range of fungi in the Didymellaceae. This study identified 22 Didymellaceae strains isolated from plants in the Convolvulaceae according to the consolidated species concept (CSC) using phylogenetic, micromorphological, and cultural features. Multilocus phylogenetic analysis inferred from nucleotide sequences of the internal transcribed spacer (ITS), large subunit (28S) of ribosomal DNA, partial DNA-directed RNA polymerase II subunit (rpb2), and β-tubulin (tub2) genes revealed well-supported monophyletic clades corresponding to 16 Didymellaceae species. Reported here for the first time from the Convolvulaceae hosts are Didymella americana, D. bellidis, D. glomerata, D. pomorum, D. segeticola, D. sinensis, D. tanaceti, Nothophoma brennandiae, N. gossypiicola, Phomatodes nebulosa, Stagonosporopsis caricae, S. heliopsidis, and S. inoxydabilis. Additionally, three new species were described: Didymella pseudomacrophylla, sp. nov. Epicoccum convolvulicola, sp. nov. and Epicoccum pseudoplurivorum, sp. nov. Seven species are reported for the first time from Russia: D. bellidis, D. segeticola, D. sinensis, D. tanaceti, N. brennandiae, P. nebulosa, and S. caricae, and one species, S. heliopsidis, for the first time from Kazakhstan.

Convolvulus arvensis is an herbaceous dicotyledonous plant in the Convolvulaceae family that is native to Europe and Asia. It is a perennial soboliferous plant and is one of the most harmful weeds. This weed is successful in many types of climates, including temperate, tropical, and Mediterranean climates, but it is most troublesome for agriculture throughout the temperate zone. In this study, several pathogenic isolates were collected from this host. The internal transcribed spacer (ITS) and large subunit (28S) or ribosomal DNA, partial DNA-directed RNA polymerase II subunit (rpb2), and β-tubulin (tub2) genes were amplified and sequenced for all the isolates studied. Further, both a multilocus phylogenetic analysis of DNA sequences and an analysis of morphological features were implemented. Based on the results obtained, all the studied isolates were found to be distinct from any described species in the genus Ascochyta and are, therefore, described here as a new species Ascochyta erotica sp. nov. The pathogenicity of A. erotica sp. nov. was also tested and confirmed on leaf segments of C. arvensis.

In nature there are species containing homologs of T-DNA genes of agrobacteria (сT-DNA) in their genomes. Such plants are called naturally transgenic ones. Interaction with the microbiota is one of the possible functions of cT-DNA, discussed in the literature. Linaria plants are the most suitable for the investigation of the probable ecological role of T-DNA, since they widely spread. The first stage in the evaluation of plant-microbial interactions involving these plants is the description of isolates with contrasting virulence for toadflax. The search and DNA-barcoding of such isolates of Phoma-like fungi was the goal of this work. 14 strains isolated from the plants of the families Plantaginaceae and Scrophullariaceae were analyzed. The of multilocus analysis included amplification and sequencing of internal transcribed spacers, a large subunit of RNA, a tubulin gene. Based on molecular data, 9 strains were assigned to the species Boeremia exigua, which has a wide range of habitats and a wide specialization. Strains of this species were virulent against L. vulgaris, but differed in aggressiveness with respect to this plant. Thus, a collection of strains was characterized, which can later be used for a more detailed study of the immune response of the naturally-transgenic L. vulgaris plant in response to inoculation with the B. exigua phytopathogen. As a result of the work, we identified the narrow host range fungi Heterophoma novae-verbascicola, and broad host range pathogens Plectosphaerella cucumerina, Phoma herbarum and Trichothecium roseum. Among them, only P. cucumerina was a weak pathogen of L. vulgaris. These results confirm the early data on the depleted mycobiota of L. vulgaris.