Lelliottia nimipressuralis (Carter 1945) Brady et al. 2013 – the Causative Agent of Bacterial Dropsy of Common Oak (Quercus robur L.) in Ukraine

Abstract

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).