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This study investigates the biological activity of bacteria in soil samples collected from sites with summer truffle (Tuber aestivum) (T) ascomata and control sites (C) without T. aestivum at three selected sites (G, M, W) in southern Poland. The number of fragments of the 16S rRNA gene in isolated DNA samples was determined by real−time PCR (qPCR) as a measure of bacterial abundance. Soil metabolic activity was assessed using the BIOLOG system. It was hypothesised that the soil samples studied would differ in terms of the enzymatic and molecular activity of the bacteria inhabiting them. The results obtained for the samples of plots G and W showed differences in bacterial abundance between the two variants. Nevertheless, in plots G and M, the metabolic activity of the microbial communities, as determined by the AWCD index after 100 h of incubation, was higher by ~0.04 and ~0.1 AWCD units, respectively, in the control variant than in the soil samples with T. aestivum. This implies that studies of bacterial communities in soil should consider both copy gene numbers and community activity as measured by the AWCD index. The results of this study deepen the knowledge about the bacterial communities and their metabolic activity in soils with T. aestivum and their potential influence on the formation of T. aestivum ascomata., Sylwan 166 (1): 54-70

The interaction of endophytic microorganisms with plants are a common occurrence that brings mutual benefits to partners. Plants are the main habitat of bacteria that live inside their tissues and do not cause disease symptoms, but affect the growth and development of plants by producing substances that promote their development. Research on the diversity of endophytic bacteria associated with forest trees is insufficient – little is known about the diversity of endophytic bacteria, and especially their function in tree tissues. Bacteria positively affecting the host tree, among others, increase biomass growth by supporting tree health. The species diversity of endophytic bacteria in plants is influenced by the plant genotype, tissue type, development phase and environmental conditions. So far, bacteria that develop in root, stem, and leaf tissues have been best known. Among the forest trees in which the occurrence and diversity of endophytic bacteria have been studied, there are species such as pine, spruce, birch and oak. The presented paper is a review of the latest literature on the subject., Sylwan 164 (6): 497-504

Microorganisms commonly inhabit all environments in which they can survive. The number of bacteria in soil depends on its structure, moisture and nutrient content, and ranges from a few hundred to several thousand per gram of soil. Qualitative and quantitative composition of bacteria mainly depends on physico−chemical agents, soil and vegetation cover, the content of biogenic elements, but also on the salinity and pollution. In the case of forest soils number of bacteria amounts to about 4.8×10 9 per 1 cm 3 of soil. In the rhizosphere, the soil directly surrounding plant roots, there are organisms that affect the biochemical activity of plants. The main representatives of bacteria, which are present in the rhizosphere layer, are species of the genera: Pseudomonas and Bacillus, Acidobacteria that protect plants against attack of pathogens. Soil microorganisms form a symbiosis with vascular plants. Because of their properties, they are effective antagonists against fungi that cause plant diseases (leaf spots, roots and shoot apices disease, as well as rot). This group includes such species as: Sclerotinia sclerotiorum, Botrytis cinerea and Colletotrichum gloeosporioides or the species belonging to Oomycetes, for example Phytophthora and Pythium. Bacteria also protect plants against harmful insects and inhibit the growth of fungal diseases. The beneficial role of bacteria is observed in the development of truffles as well. They are responsible for providing nitrogen to the mycelium forming fruiting bodies. Bacteria improve plant growth and protect their host against drought. Understanding the diversity of bacteria that have important role in the functioning of ecosystems, including forest ecosystems, remains a challenge for microbiologists., Sylwan 161 (2): 155-162