Wheat sharp eyespot is a serious disease caused by the phytopathogens Rhizoctonia cerealis and R. solani. Some species in the genus Streptomyces have been identified as potential biocontrol agents against phytopathogens. In this investigation, the physiological, biochemical, phylogenetic and genomic characteristics of the strain HU2014 indicate that it is a novel Streptomyces species most closely related to Streptomyces albireticuli. HU2014 exhibited strong antifungal activity against R. cerealis G11 and R. solani YL-3. Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) on the four extracts from the extracellular filtrate of HU2014 identified 10 chemical constituents in the Natural Products Atlas with high match levels (more than 90%). In an antifungal efficiency test on wheat sharp eyespot, two extracts significantly reduced the lesion areas on bean leaves infected by R. solani YL-3. The drenching of wheat in pots with spore suspension of HU2014 demonstrated a control efficiency of 65.1% against R. cerealis G11 (compared with 66.9% when treated by a 30% hymexazol aqueous solution). Additionally, in vitro and pot experiments demonstrated that HU2014 can produce indoleacetic acid, siderophores, extracellular enzymes, and solubilized phosphate, and it can promote plant growth. We conclude that HU2014 could be a valuable microbial resource for growth promotion of wheat and biological control of wheat sharp eyespot.
Goal. To establish the influence of the genotype of winter wheat on the presence of Alternaria sp. in the seeds of winter wheat under different growing conditions, for different periods of time, among varieties from different original institutions of Ukrainian and foreign selection. Methods. Field — cultivation of wheat varieties in the Forest-Steppe of Ukraine; organizational — collection of seed samples; laboratory — analysis of the mycoflora of winter wheat seeds by biological method on the PGA, determination of Alternaria fungi on the environment of the PCA; analytical and mathematical — analysis of the obtained results and their statistical comparison. Results. The study of the influence of the variety on the isolation of Alternaria fungi for their cultivation in different years for the period from 2011 to 2020 and in different growing conditions proved the existence of a significant difference in their total amount and number of individual species, especially dominant. Differences were noted in the presence of Alternaria sp. inside the seeds grown in two climatic zones (Polissya and Forest-Steppe), on farms and in experimental fields. Three-year observation of the species of these fungi on two varieties from one originator showed their different isolation: both the presence of certain representatives and the number of their isolation. Analysis of 9 and 17 genotypes of wheat of Ukrainian and foreign selection during 2019 and 2020 also showed a different picture of the population of Alternaria fungi. Conclusions. Significant influence of genotype on the selection of Alternaria sp. was installed. Based on several years of studying the population of winter wheat seeds with Alternaria fungi, genotypes with a smaller presence were identified: in 2013—2015 — Gordovyta variety, in 2019—2020 — Emil, Pylypivka. It should be borne in mind that fewer alternative fungi reduce the presence of their mycotoxins, but increase the number of other fungi in the mycoflora, sometimes more dangerous.
The microbiota of winter wheat seeds from the North-East of Ukraine was studied by a biological method. Its considerable variability is established over three years (2017–2019). The effect of the treatment agents on most microorganisms of wheat seed microbiota in Ukraine, rather than on its genera and species, is shown. It has been proven that fungicides deleted some species and did not affect the development of others. Chemicals replaced some species or genera of fungi with others or even other microorganisms. Biological seed treatment (Phytosporin-M) has caused less microbiota change than chemical treatment (Maxim 0.25 FS, Rostock, Kinto Duo). Fungicides have replaced the dominance of Alternaria spp. (2017 – 57.8%, 2018 – 63.5%) for the dominance of yeast (Rostock – 54%) and Aureobasidium pullulans (Maxim 0.25 FS – 84.2%) in 2017, bacteria (Maxim 0.25 FS – 72.3%, Rostock – 53.8%) – in 2018. A. pullulans dominated in the microbiota of winter wheat seeds in 2019. The highest amount of A. pullulans was noted for the treatment of seeds by Phytosporin-M (85.9%). The biological seed treatment reduced the amount of Nigrospora spp. and Alternaria spp. Several times (3 and 5, respectively), chemical agents did not give Nigrospora spp. germination reduced the amount of A. pullulans, Alternaria spp. in 2019. Maxim 0.25 FS, Rostock 50%, and Kinto Duo delayed seed germination and seedling development on agar medium and soil, whereas Phytosporin-M – on the contrary, promoted the growth of seedlings and significantly exceeded control.
Biocontrol microorganism have a diverse range of activities and they have been focused on potential biocontrol agents in agriculture. They can induce plant defensed response and enhance plant disease resistance. Streptomyces sp. produce active metabolites that can inhibit the growth of phytopathogens. Induced resistance is usually indicated by the activity of Peroxidase (POD), Polyphenoloxidase (PPO), and Phenylalanine ammonia-lyase (PAL) or other defense enzymes. The related reports mainly focused on disease control or promoting growth of cash crops or vegetables, but less on wheat presently. Moreover, the information about the concentration of fermentation broth and mycelia of Streptomyces affected the quantitative changes of defensed enzyme activities is limited. In this study, we started from isolating a Streptomyces strain, named S. sp. strain HU2014, and demonstrated (POD), (PPO), (PAL) enzymes in different concentration of the mycelia (M) and extracellular filtrate (EF) of the strain with the application of soil drench treatment. The enzyme activities were determined by visible spectrophotometry. The results showed that the activities of POD and PAL at the concentration of 103-fold dilution of the EF increased significantly to some extent in comparison with untreated control, by 173.86 % (P < 0.05) and 71.92 % (P < 0.05), respectively. In the range of different concentration of the M, POD and PPO activities were enhanced with the increasing of dilution ratio, but the difference was not significant. It is expected to be an excellent resource for the development of new biological preparations.
Seed-born fungi of wheat interact with the plant at various stages of its development and with each other. With the highest growth rate, they should be isolated because of competition. The purpose of this study was to compare the growth of colonies on a nutrient medium for the gradation of fungal genera and species from wheat seeds according to aggressiveness. These data helped concluding on the effectiveness of mycoexpertise of winter wheat seeds. Potatoglucose agar (PGA) was used for the analysis of the fungal complex. Seven-day fungal cultures were sown in the centre of Petri dishes. Linear growth of fungal colonies on PGA with gentamicin was determined. The specific features of the development of 12 representatives of seeds mycobiota from the Northeast of Ukraine of the 2017-2019 harvest were investigated. The dominance of Alternaria sp. and a slight release of Fusarium sp. were established by analysis of the fungal complex. The first comparison of the linear growth of Fusarium graminearum, F. poae, and Alternaria tenuissima in 2017 showed that Fusarium colonies grow faster on nutrient medium. In 2018, the growth characteristics of A. arborescens, which quickly became dominant in wheat seeds mycoflora, and the littlecommon Trichothecium roseum were studied in detail. By comparing the growth of fast-growing F. graminearum with the common Aureobasidium pullulans and the aggressive Nigrospora oryzae, the fastest development of the third and the slowest of the second species was established. F. poae filled the Petri dish on day 6, Penicillium – on day 22. In 2019, in the first experiment comparing F. poae, F. sporotrichioides, and A. avenicola, the second species had the worst growth rates. It became the second fastest growing colony in the study of the growth of seven species in the second experiment. Isolates of N. oryzae in 2018 were more aggressive than in 2019. Specific features of colony growth on PGA did not affect the effectiveness of the analysis of mycobiota of winter wheat seeds. N. oryzae had the highest radial speed under the general dominance of Alternaria sp. Fusarium sp. (F. poae, F. sporotrichioides, F. verticillioides, and F. graminearum) and B. sorokiniana developed rapidly. A. arborescens and A. avenicola grew at the same level as A. pullulans. Penicillium and T. roseum lagged behind other fungi in speed and filled Petri dishes for the longest time. A. tenuissima had the lowest radial growth rate
У 2019–2021 рр. у виноградному агроценозі навчальної лабораторії садівництва та виноградарства Сумського національного аграрного університету проведено дослідження щодо вивчення впливу агроекологічних чинників на рівень розвитку основних мікозів винограду. Наводяться дані про ступінь стійкості виноградних рослин різних сортів до основних фітопатогенів винограду (мілдью, оідіум) у типових ґрунтово-кліматичних умовах північно-східного Лісостепу України. Досліджувалась колекція винограду вітчизняної та зарубіжної селекції, яка налічує близько 30 сортів та форм. Встановлено, що метеорологічні умови 2021 р. сприяли епіфітотійному розвитку мілдью і оідіуму. За період досліджень 2019–2021 рр. спостерігались коливання рівня стійкості проти хвороб в залежності від погодних умов. Виділено сорти та форми винограду з високою стійкістю проти збудників мілдью (P. viticola) та оідіуму (U. necator (Schw.): Байконур, Юпітер, кишмиш 342/вєнгерський, Орігінал, Лідія (максимальне ураження листя – 2,5–3,0 бали, грон – 2,0–3,0 бали, середнє – 2,3–2,8 бали). Відзначено високий рівень стійкості сорту Юпітер (середній бал ураження 2,3) до збудника оідіуму порівняно з контролем (сорт Лідія – 2,5 бали). Доведено, що більшість досліджуваних сортів (Подарок Нєсвєтая, Пам’яті учителя, Ромбік, Столєтіє, Смарагд, Віктор, Благовєст, Нізіна, Богатяновський, Ланселот, Блєк гранд, Лівія, Одеський сувенір, Ванюша, Лорано, Флора, кишмиш Запорожський) проявили середню стійкість проти мікозних хвороб винограду (мілдью та оідіуму) на рівні 3,0–3,5 балів. Найбільш сприйнятливими до дії збудників основних грибних патогенів виявились форми винограду Ізюмінка (4,1 бали проти мілдью, 4,0 бали проти оідіуму), Красноє пламя (4,6 бали проти мілдью, 4,3 бали проти оідіуму). Серед досліджених сортів і гібридних форм імунних до оідіуму і мілдью не виявлено. Дослідженням встановлено, що біологічні особливості сортів винограду Байконур, Юпітер, кишмиш 342/вєнгерський, Орігінал, Лідія, Подарок Нєсвєтая, Пам’яті учителя, Ромбік, Столєтіє, Смарагд, Віктор, Благовєст, Нізіна, Богатяновський, Ланселот, Блєк гранд, Лівія, Одеський сувенір, Ванюша, Лорано, Флора, кишмиш Запорожський відповідають умовам вирощування та можуть бути рекомендовані до впровадження у виробництво в агрокліматичній зоні північно-східного Лісостепу України. Вирощування сортів з високим адаптивним потенціалом дозволить отримувати екологічно чисту продукцію високої якості.
Studies were conducted during 2017‒2019 based on the training laboratory of horticulture and viticulture of the Sumy National Agrarian University in the conditions of the North-Eastern Forest-Steppe of Ukraine. It was found that the pear was massively affected by rust. This is a fungal disease that was rarely found in fruit orchards of the North-Eastern Forest-Steppe of Ukraine. Rust infected pear trees very rarely in previous years. Only single spots were found on the leaves of the pear. Since 2015, the development of the disease has noticeably accelerated from year to year. There was a massive rust damage of the pear in the region in 2019. The prevalence of the disease reached 100 % in almost all varieties. Mostly the leaves were affected, not to a large extent the shoots of the pear. On the fruits of the external signs of the disease were not detected. During the years of research, weather conditions were optimal for the spread of fungal diseases. Only the aecial stage of the fungus was observed on the pear. The aecial stage of the pathogen is the most harmful. Affected pear leaves fall prematurely. Studies were conducted on pear varieties Lymonka, Petrovska, Medova, Osinnia Yakovlieva, Chyzhovska, Noiabrska, Bere Desiatova, Uliublenytsia Klappa, which showed different degrees of rust damage. The disease manifested itself most significantly (5 points) on the varieties, Uliublenytsia Klappa and Bere Desiatova. Not one of the varieties did not show high resistance to the pathogen. The pear of the Chyzhovska variety was less affected, with a defeat score of 3 (18.8 %) in 2017 and 4 (32.3 % and 44.1 %) in 2018‒2019. It is known that the life cycle of the rust pathogen Gymnosporangium sabinae (Dicks.) G. Winter occurs on two plants: pear and juniper. The pathogen from juniper goes on the pear and vice versa. Pear trees do not become infected from each other. On the territory adjacent to the fruit garden of Sumy National Agrarian University, a survey of plantings of different types of juniper was conducted. There were no visible signs of the disease on the juniper. At the same time, pear trees were highly infected with the pathogen. Perhaps the spores of the fungus can spread far through air currents. But at the same time, possible changes in the life cycle of the pathogen in the conditions of this region. Clarification of this circumstance requires deeper further research.
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