The aim of this study was the identification of the causative agent of the basal glume rot of wheat Pseudomonas syringae pv. atrofaciens from the affected weeds in wheat crops, and determination of its virulent properties. Isolation of P. syringae pv. atrofaciens from weeds of wheat crops was carried out by classical microbiological methods. To identify isolated bacteria, their morphological, cultural, biochemical, and serological properties as well as fatty acids and Random Amplification of Polymorphic DNA (RAPD)-PCR (Polymerase chain reaction) profiles with the OPA-13 primer were studied. Pathogenic properties were investigated by artificial inoculation of wheat plants and weed plants, from which bacteria were isolated. For the first time, bacteria that are virulent both for weeds and wheat were isolated from weeds growing in wheat crops. It was shown that the fatty acids profiles of the bacteria isolated from the weeds contained typical for P. syringae pv. atrofaciens fatty acids, in particular, hydroxy acids: 3-hydroxydecanoic, 2-hydroxydodecanoic, and 3-hydroxydodecanoic. RAPD-PCR profiles of the newly isolated strains were identical to those of the collection strains P. syringae pv. atrofaciens UCM B-1011 and P. syringae pv. atrofaciens UCM B-1014 and contained a dominant fragment of 700 bp. The isolated strains, according to their phenotypic and genotypic properties, were identified as P. syringae pv. atrofaciens. It was established that the causative agent of basal glume rot of wheat P. syringae pv. atrofaciens is polyphagous and capable of infecting a wide range of plants. The main control measure for cereals diseases caused by P. syringae pv. Atrofaciens—crop rotations with nonhost species, should be revised, and alternative control methods must be proposed.

Due to the lack of control over the spread of pathogens and effective pesticides with antibacterial activity bacterial diseases cause significant economic losses in vegetable production including tomatoes. Therefore, the search for ways of biocontrol of bacterial diseases pathogens in vegetable crops is an extremely urgent problem. The literature review presents a systematic analysis of modern measures of agrotechnical, chemical and biotechnological control of bacterial diseases in tomatoes, and increasing the resistance degree of these crops against phytopathogenic bacteria using traditional methods, cell selection and the involvement of genetic engineering approaches. It is shown that agrotechnical measures are preventive in nature, while using chemicals and antibiotics has side effects, in particular phytotoxicity and the appearance of resistant strains of pathogens. Effective and economically viable is the use of biotechnological preparations and the cultivation of the varieties resistant to pathogens of bacterial diseases in vegetable crops. Selection of varieties resistant to phytopathogenic bacteria is based on the use of wild species as resistance sources. The creation of genetically modified plants containing avr-genes, resistance genes against bacterial phytotoxins, PR-proteins and AMP is promising.

A significant part of the used pesticides does not reach the target organisms and, while remaining in the agrophytocenosis, influences all living organisms in it. Having a toxic and often mutagenic effect, pesticides induce morphological and physiological changes in the cells of microorganisms and are the cause of phenotypic heterogeneity of their populations. However, the effect of pesticides on phytopathogenic bacteria as non-target microorganisms remains out of the field of view for most researchers. However, the use of pesticides can lead to expansion of the diversity of existing phytopathogens and, as a consequence, complications of identification of the pathogens, loss of resistance by plants varieties, and increased harm from diseases caused by them. This study is focused on the effect of pesticides used in tomato plantations on the causative agent of bacterial speck of this crop—Pseudomonas syringae pv. tomato. The studies were carried out using the methods of classical microbiology. The mutagenic action of pesticides was recorded, taking into account the increase of the number of streptomycin resistance mutations in bacteria in the case of pesticide action. It is established that the fungicide aluminium phosethyl is characterised by a bacteriostatic effect on P. syringae pv. tomato. Deltamethrin insecticide does not affect the growth of P. syringae pv. tomato. However, there is an increase in the frequency of streptomycin resistance mutations in both studied strains of P. syringae pv. tomato after using deltamethrin. It is shown that the frequency of occurrence of R (rough colonies) forms of P. syringae pv. tomato IZ28 and IZ46 after using deltamethrin increased by 100 times when in comparison to the frequency of spontaneous morphological dissociation, or smooth-to-rough (S-R) mutation, of these bacteria. Therefore, aluminium phosethyl is characterised by moderate bacteriostatic action against P. syringae pv. tomato. Deltamethrin does not influence the growth of the pathogen of tomato speck but increases the frequency of formation of StrR mutants and R forms of phytopathogenic bacteria.

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Recently, in the greenhouses of Ukraine, a sharp increase in the infestation of tomato plants with soft (wet) rot has been registered. Purpose: To identify the pathogen of the soft rot, study its biological properties and develop practical recommendations for plant protection measures. Methods: The work was performed using classical microbiological and biochemical research methods. The API 20E (Bio Merieux) test system was used to study the physiological and biochemical properties of the bacteria. The study of bacterial fatty acids was carried out by mass-spectrometry. Results: Using a bacteriological analysis of tomato plants selected in greenhouses of the Kyiv region, for the first time, virulent strains from this crop were identified and assigned, according to their physiological, biochemical, morphological and cultural characteristics, to the Pectobacterium carotovorum species. The fatty acid profile of the total cell lipids of the isolated strains was distinguished by the presence of 1,13‒1,17%, of 3-hydroxytetradecanoic acid, which is typical for P. carotovorum subsp. carotovorum. It was found that the isolated strains were sensitive to oxychloride and copper hydroxide-based fungicides with 10,5 to 17,5 mm growth inhibition zones. Conclusion: The causative agent of soft (wet) rot of tomatoes in greenhouses is P. carotovorum subsp. сarotovorum. Fungicides with oxychloride and copper hydroxide are recommended as the active agents to protect tomato plants from the pathogen.

Background: In recent years, there has been a growing scientific interest in the biodiversity and function of endophytic bacteria, as well as the prospects for their practical use. Objective: The purpose of this work was to isolate endophytic microorganisms from generative organs of the European black nightshade (Solanum nigrum L.), assess their biological activity, and test their growth-promoting/protective effects in tomato (Solanum lycopersicum L.) plants. Methods: From the tissues of generative organs of S. nigrum plants, 14 strains of endophytic microorganisms were isolated. Most of them belonged to Bacillus sp. The physiological and biochemical properties and enzymatic and oxidative metabolism of some of them were studied. Sequence analysis of 16S rRNA fragments revealed 99,65% similarity of BA1s-OSN-0820 and BAXS-OSN-0820 isolates to B. amyloliquefaciens strains, while the ITS sequence of the RHC-OSN-0820 isolate showed 99,65% of similarity to Rhodotorula kratochvilovae. Results: The actions of these endophytes against tomato pathogenic bacteria and fungi were then tested. The isolates had a significant bacteriostatic effect against Xanthomonas campestris, the causative agent of black bacterial spotting of leaf, and Clavibacter michiganensis, the causative agent of bacterial wilt, with a lower effect against Pseudomonas syringae, the causative agent of bacterial spotting. Isolates also showed selectivity against micromycetes that cause mycosis in tomatoes grown indoors, such as Fusarium oxysporum, Alternaria solani, Botrytis cinerea, Sclerotinia sclerotiorum, and F. acuminatum. In particular, the highest antifungal activity was detected against S. sclerotiorum and fungi of the Fusarium genus. Inoculation of tomatoes with endophytic microorganisms revealed a positive effect on seed germination efficiency and the stimulation of seedling growth. Thus, the effectiveness of interspecific transfer of endophytic microorganisms from a wild, S. nigrum, to a cultivated Solanum species, S. lycopersicum, was reported. Conclusion: A consortium of plant-associated microorganisms isolated from a wild relative has a positive effect on the germination of tomato seeds, stimulating the formation of the root system and nutrition of seedlings. The antagonism of the isolates against phytopathogenic fungi and bacteria provides long-term protection during the most critical stages of plant development and has prospects for the development of microbial biologics for cultivated plants of the Solanaceae family.

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The aim of the work is to study the effect on phytopathogenic bacteria of the species P. syringae of microbiological preparations and substances with aelysitor activity, as well as to analyze the resistance of plant varieties to the causative agents of bacterial diseases of this species. Methods. The antibacterial activity of microbiological preparations registered in Ukraine on the basis of Bacillus subtilis, Pseudomonas fluorescens, Pseudomonas aureofaciens, Azotobacter chroococcum was determined by the method of wells on potato agar. To assess the chitosan’s helix activity, the vegetative tomato plants were treated with a solution of chitosan at a concentration of 0.4%: in the phase of 2—3 true leaves and in the flowering phase. One day after the second treatment, it was carried artificial inoculation of the leaves, stalks, and ovaries with a suspension of cells P. syringae pv. tomato IZ-28 titer 107 CFU/ml and took into account the symptoms of artificial infection. To determine the resistance of wheat and tomato varieties, artificial inoculation of plants was performed in a vegetative house with a suspension of P. syringae pv. atrofaciens UKM B-1011 and P. syringae pv. tomato IZ-28, respectively. Results. Microbiological preparations based on bacteria B. subtilis, P. fluorescens, P. aureofaciens had different antibacterial activity against pathogens of basal bacteriosis of wheat P. syringae pv. atrofaciens, bacterial spot of P. syringae pv. tomato and angular cucumber spot P. syringae pv. lachrymans. Treatment of infected tomato plants with low-molecular chitosan resulted in a slight inhibition of the development of bacterial mottling. Conclusions. Effective and economically viable is the use of biotechnological preparations and the cultivation of the varieties resistant to pathogens of bacterial diseases in vegetable crops.