Search Results (4)

Helvella bachu, an ectomycorrhizal fungus, forms a symbiotic relationship with Populus euphratica, a rare and endangered species crucial to desert riparian ecosystems. In this study, endofungal bacteria (EFBs) within the fruiting bodies of H. bachu were confirmed by a polyphasic approach, including genomic sequencing, real-time quantitative PCR targeting the 16S rRNA gene, full-length and next-generation sequencing (NGS) of the 16S rRNA gene, and culture methods. The genera Stenotrophomonas, Variovorax, Acidovorax, and Pedobacter were abundant in the EFBs of fruiting bodies associated with three Populus hosts and were consistently present across different developmental stages. Notably, S. maltophilia and V. paradoxus were detected in high abundance, as revealed by full-length 16S rRNA sequencing, with S. maltophilia also isolated by culture methods. KO-pathway analysis indicated that pathways related to primary, secondary, and energy metabolism were predominantly enriched, suggesting these bacteria may promote H. bachu growth by producing essential compounds, including sugars, proteins, and vitamins, and secondary metabolites. This study confirmed the presence of EFBs in H. bachu and provided the first comprehensive overview of their structure, functional potential, and dynamic changes throughout fruiting body maturation, offering valuable insights for advancing the artificial domestication of this species. Full article

A mycelial culture of the African basidiomycete Echinochaete cf. brachypora was studied for biologically active secondary metabolites, and four compounds were isolated from its crude extract derived from shake flask fermentations, using preparative high-performance liquid chromatography (HPLC). The pure metabolites were identified using extensive nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HR-MS). Aside from the new metabolites 1-methoxyneomarinone (1) and (E)-3-methyl-5-(-12,13,14-trimethylcyclohex-10-en-6-yl)pent-2-enoic acid (4), the known metabolites neomarinone (2) and fumaquinone (4) were obtained. Such compounds had previously only been reported from Actinobacteria but were never isolated from the cultures of a fungus. This observation prompted us to evaluate whether the above metabolites may actually have been produced by an endosymbiontic bacterium that is associated with the basidiomycete. We have indeed been able to characterize bacterial 16S rDNA in the fungal mycelia, and the production of the metabolites stopped when the fungus was sub-cultured on a medium containing antibacterial antibiotics. Therefore, we have found strong evidence that compounds 1–4 are not of fungal origin. However, the endofungal bacterium was shown to belong to the genus Ralstonia, which has never been reported to produce similar metabolites to 1–4. Moreover, we failed to obtain the bacterial strain in pure culture to provide final proof for its identity. In any case, the current report is the first to document that polyporoid Basidiomycota are associated with endosymbionts and constitutes the first report on secondary metabolites from the genus Echinochaete. Full article

Fungi serve as a biological scaffold for bacterial attachment. In some specialized interactions, the bacteria will invade the fungal host, which in turn provides protection and nutrients for the bacteria. Mechanisms of the physical interactions between fungi and bacteria have been studied in both clinical and agricultural settings, as discussed in this review. Fungi and bacteria that are a part of these dynamic interactions can have altered growth and development as well as changes in microbial fitness as it pertains to antibiotic resistance, nutrient acquisition, and microbial dispersal. Consequences of these interactions are not just limited to the respective microorganisms, but also have major impacts in the health of humans and plants alike. Examining the mechanisms behind the physical interactions of fungi and bacteria will provide us with an understanding of multi-kingdom community processes and allow for the development of therapeutic approaches for disease in both ecological settings. Full article

Endofungal bacteria are bacterial symbionts of fungi that exist within fungal hyphae and spores. There is increasing evidence that these bacteria, alone or in combination with their fungal hosts play a critical role in tripartite symbioses with plants, where they may contribute to plant growth and disease resistance to microbial pathogens. As the frequency of bacteria in fungi is commonly very low, breakthroughs in technology such as molecular taxonomy and laser scanning microscopy were required to establish the functional contribution of these bacteria in complex symbioses. Yet, the overall biological significance of endofungal bacteria is largely unknown and further progress in understanding is hampered by a very few biological systems where endofungal bacteria have been described mechanistically. We review here the current knowledge on endobacteria (EB) and their role in different types of fungal symbioses with plants. We show that various attempts to cure fungal cells from endobacteria failed, further suggesting that they play a crucial role in the symbiosis. Moreover, isolation of some of the endobacteria from their fungal hosts allowed confirming their autonomous beneficial activity such as plant growth promotion and resistance-inducing activity. The review addresses the potential agricultural significance of endofungal bacteria and their role in supporting sustainable agriculture by promoting plant growth, improving plant resistance, and decreasing yield loss caused by many microbial pathogens. Full article