The article presents the symptomatic characteristics of vascular-parenchymal bacteriosis, which is quite common on forest woody plants, caused by the causative agent of bacterial dropsy. It was shown that a characteristic feature of this bacteriosis is the formation of various shapes and sizes of ulcers, in the places of formation of which there is a release of a dark, almost black, exudate. It is emphasized that during the study of the vascular system of common oak trees, its dark coloration is noticeable. Now there is a chronic course of the disease with the presence of dieback of individual branches in the crown. It was established that the causative agent of bacterial dropsy is Lelliottia nimipressuralis; its physiological and biochemical characteristics are given. The aim of the work is the bacteriological study of wood samples with typical signs of bacterial dropsy, study of morphological, cultural and biochemical properties of the causative agent of bacterial dropsy of oak. Methods. Classical microbiological, phytopathological, biochemical, statistical methods were uses in the work. If a bacterial dropsy was suspected, diagnostic methods were combined, with the help of which the etiology of the disease was established: an accurate analysis of symptoms; a thorough microscopic examination of the affected parts of plants; isolation and identification of the pathogen using NEFERMtest24 MikroLaTE, ErbaLachema, API 20E test systems and the like. Results. We have noted the habitual manifestations of the bacterial dropsy of the common oak. From the lesion, where dark brown areas of wood appeared under the bark in the area of the ulcer against the background of healthy light-colored wood, isolated bacterial isolates were identified by morphological and physiological-biochemical properties as Lelliottia nimipressuralis (Brady et al. 2013) – the causative agent of bacterial dropsy of oak (now Enterobacter nimipressuralis). It was found that isolates from common oak, like the collection strain E. nimipressuralis 8791, are gram-negative. It was shown that the studied bacteria are facultative anaerobes and use glucose both under aerobic and anaerobic conditions. They do not form gelatinase and protopectinase. Exhibit a positive Voges-Proskauer reaction. Bacteria use glucose, arabinose, rhamnose, amygdalin, and melibiose as the only source of carbon nourishment. The bacteria do not use inositol and sorbitol. They do not form indole and hydrogen sulfide (H2S), but are capable of reducing nitrates. They contain arginine dehydrolase, ornithine decarboxylase, β-galactosidase, but not lysine decarboxylase, and urease. Conclusions. It has been established that the diseases that we discovered are, by all symptomatic signs, a systemic, vascular-parenchymal bacteriosis, known as bacterial dropsy of oak, which affects all tissues, plant parts and generative organs at all stages of ontogenesis. According to the morphological, physiological and biochemical properties of bacterial dropsy isolated by us during the research, we identified the causative agent of bacterial edema of oak – Lelliottia nimipressuralis (Carter 1945).
Given the forestry, the ecological and economic value of forests with the participation of Fraxinus excelsior and taking into account the intensive deterioration of their phytosanitary status in modern conditions, a comprehensive study of symptoms, causes, and pathogenesis of ash tuberculosis with further development of effective protection measures, including using biological products based on Bacillus sp. and other myco- and microorganisms, is a particularly relevant area of research. The aim of the research is to identify negative abiotic and biotic factors in the pathology of F. excelsior. In the process of research general scientific and special research methods were used (microbiological, mycological, phytopathological, entomological, and silvicultural-ecological methods). It is emphasized that the pathology of the common ash is a multifaceted phenomenon with interrelated processes of infectious and non-infectious nature, which in recent years has led to epiphytic dieback and now has a tendency to increase. It has been established that tuberculosis of F. excelsior is the most common and harmful disease within the study region and causes more economic than environmental damage. Bacteria of the genera Pseudomonas sp., Erwinia sp., and Xanthomonas sp., as well as micromycetes, which mainly take the place of the concomitant mycobiota. There are five stages (phases) of the development of tuberculosis pathology, which differ significantly in symptoms. The species composition of harmful insects has been identified. It is shown that hydrothermal stress is a catalyst for the epiphytic dieback of common ash. Direct dependence of the spread of tuberculosis on the share of ash in the stands of different age groups was revealed. In the study area, tuberculosis reaches epiphytotics on F. excelsior, especially at a young age. The expediency of distinguishing the causes and pathological processes associated with ash tuberculosis is indicated, so as not to confuse the disease-catalyzing factors and the factors that lead to the complete degradation of ash stands
In recent decades, in many regions of the planet, there has been a widespread deterioration in the health condition and dieback of dark coniferous forests, caused by the combined action of various stress factors of biotic and abiotic origin. Forests with the participation of species of the genus Abies Mill. are particularly prone to degradation and dieback. The aim of the research is to study the symptoms of bacterial wetwood disease of Abies alba in the Ivano-Frankivsk region (state enterprise ‘Kutske forestry’) and to determine the anatomical, morphological and cultural properties of the pathogen. Some of the common symptoms of the disease include cracks and ulcers on the trunks with exfoliated rhytidome and exudate secretion, massive development of epicormic shoots, saturated xylem and phloem, wet rot with a characteristic odour of fermentation and pathological nucleus. Based on the syntaxonomic analysis of fir forests, an attempt has been made to identify the objective causes that lead to excessive development of phytopathogens and dieback of Abies alba. Our research established that the primary cause of dieback of Abies alba Mill. forests is a systemic, vascular–parenchymal disease known as bacterial wetwood of fir, which affects all plant tissues at all stages of ontogenesis. We isolated and experimentally confirmed that the causative agent of the disease is a phytopathogenic bacterium Lelliottia nimipressuralis (Carter 1945) Brady et al. 2013, which also causes bacterial wetwood in many species of forest woody plants, and also studied its common morphological, physiological and biochemical properties.
In this study, the characterization of several bacterial diseases affecting silver birch (Betula pendula Roth.), common ash (Fraxinus excelsior L.), white poplar (Populus alba L.), and white willow (Salix alba L.) in Ukraine were described. The typical symptoms, features of pathogenesis, and characteristics of the causative agents of the most common bacterial diseases of these tree species were shown. The following types of bacterioses were noted to be especially dangerous, namely, bacterial wetwood, fire blight, bacterial canker, and tuberculosis. Bacterial necrosis of the bark was a less dangerous disease. At the same time, all of the listed types of bacterioses were registered within the forest areas of the investigated region. The study revealed that bacterial wetwood of birch and poplar was caused by Lelliottia nimipressuralis; the bacterial canker of poplar is Pseudomonas syringae (Pseudomonas syringae f. populi and Pseudomonas cerasi); the fire poplar blight is caused by Pseudomonas cerasi (P. syringae); the common ash tuberculosis is caused by Pseudomonas syringae pv. savastanoi; and the bacterial wilt of the willow is caused by Brenneria salicis. The phenomenon of the introduction of microorganisms of different functional orientations as well as the formation of conditions for their activity in the rhizosphere of plants have been studied. In the future, it will provide the development of effective methods for the rapid identification of causative agents of bacterioses and plant protection measures based on multi-functional microbiological preparations based on highly effective strains of microorganisms.
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