Early blight (EB) is a destructive disease affecting potato and tomato plants in Russia, caused by a heterogeneous group of plant pathogenic Alternaria fungi. The current species delimitation in Alternaria sect. Porri with medium to large conidia and a long (filamentous) beak is based on molecular data. In this study, the ITS, GAPDH, RPB2, TEF1, and Alt a 1 gene regions were analyzed in 41 large-spored Alternaria isolates obtained from diseased potato and tomato plants collected from 13 regions in Russia. Our data revealed five pathogenic species (A. alternariacida, A. grandis, A. linariae, A. protenta, and A. solani). Two species (A. solani and A. linariae) were found to be associated with early blight of tomato. Alternaria linariae and A. protenta were confirmed as the major causal agents of tomato and potato early blight, respectively. There were no phylogenetic groupings among tested Russian Alternaria isolates associated with their locality.
13 November 2017 in Journal of Plant Diseases and Protection
Features of the biochemical adaptations of alkaliphilic fungi to exist in extreme environments could promote the production of active antibiotic compounds with the potential to control microorganisms, causing infections associated with health care. Thirty-eight alkaliphilic and alkalitolerant Emericellopsis strains (E. alkalina, E. cf. maritima, E. cf. terricola, Emericellopsis sp.) isolated from different saline soda soils and belonging to marine, terrestrial, and soda soil ecological clades were investigated for emericellipsin A (EmiA) biosynthesis, an antifungal peptaibol previously described for Emericellopsisalkalina. The analysis of the Emericellopsis sp. strains belonging to marine and terrestrial clades from chloride soils revealed another novel form with a mass of 1032.7 Da, defined by MALDI-TOF Ms/Ms spectrometers, as the EmiA lacked a hydroxyl (dEmiA). EmiA displayed strong inhibitory effects on cell proliferation and viability of HCT 116 cells in a dose- and time-dependent manners and induced apoptosis.
The adaptations that alkaliphilic microorganisms have developed due to their extreme habitats promote the production of active natural compounds with the potential to control microorganisms, causing infections associated with healthcare. The primary purpose of this study was to isolate and identify a hydrophobin, Sa-HFB1, from an alkaliphilic fungus, Sodiomyces alkalinus. A potential antifungal effect against pathogenic and opportunistic fungi strains was determined. The MICs of Sa-HFB1 against opportunistic and clinical fungi ranged from 1 to 8 µg/mL and confirmed its higher activity against both non- and clinical isolates. The highest level of antifungal activity (MIC 1 µg/mL) was demonstrated for the clinical isolate Cryptococcus neoformans 297 m. The hydrophobin Sa-HFB1 may be partly responsible for the reported antifungal activity of S. alkalinus, and may serve as a potential source of lead compounds, meaning that it can be developed as an antifungal drug candidate.
Modern taxonomic studies of Agaricomycetes rely on the integrative analyses of morphology, environmental data, geographic distribution, and usually several DNA loci. However, sampling and selection of DNA loci for the analyses are commonly shallow. In this study, we suggest minimal numbers of necessary specimens to sample and DNA loci to analyze in order to prevent inadequate taxonomic decisions in species groups with minor morphological and genealogical differences. We sampled four unlinked nuclear DNA gene regions (nuc rDNA ITS1-5.8S-ITS2, gh63, rpb2, and tef1) to revise the systematics of a common wood-decaying species Basidioradulum radula (Hymenochaetales) on an intercontinental set of specimens collected in the Northern Hemisphere. The DNA loci analyzed violate the genealogical concordance phylogenetic species recognition principles, thus confirming a single-species interpretation. We conclude that Hyphodontia syringae is a younger synonym of B. radula.