On 15 December at 11:15 Mari Pent will defend her doctoral thesis “Bacterial communities associated with fungal fruitbodies” for obtaining the degree of Doctor philosophiae (in Botany and Mycology).
Dr. Kadri Põldmaa, University of Tartu
Dr. Mohammad Bahram, University of Tartu, and Swedish University of Agricultural Sciences (Sweden)
Dr. Sari Timonen, University of Helsinki (Finland)
Eukaryotic organisms host various microbes which can play an important role in enhancing host’s health, development and fitness. Although fungi represent a species-rich and diverse group of eukaryotes, the bacterial communities associated with fungi, especially those residing in fungal fruitbodies, have received little attention. Additional knowledge about fungal-bacterial interactions is important not only for reaching a better understanding of their ecological role, but also for the improvement of fungal cultivation. The aim of the current PhD thesis was to study the structure and functions of bacterial communities in fruitbodies of different basidiomycete species by using mainly next-generation sequencing methods. In addition, the role of host-derived and environmental factors were analyzed with particular emphasis on the effect of the surrounding soil in shaping the bacterial communities in fungal fruitbodies. The results indicated that host characteristics affect the bacterial community composition in fungal fruitbodies more strongly than the environmental factors. Among the host-associated factors, the host taxonomy, derived from the phylogeny, had the strongest effect, followed by the impact of the fungal functional guild. For the first time it was found that in analogy with other eukaryotes the structure and function of bacterial communities are strongly determined by the host’s genotype within a fungal species. The chemical characteristics of fruitbodies vary among different fungal groups and between saprotrophic and ectomycorrhizal fungi and have an important role shaping the bacterial communities in fruitbodies. Among environmental factors, several soil charactersitics, especially pH, affected the bacterial community composition in fruitbodies. In addition, the hypothesis that most of the endofungal bacteria originate from the surrounding soil was confirmed. Most of the functional genes of endofungal bacteria are involved in the metabolism of carbon compounds, amino acids, proteins, cofactors and vitamins. Thus, bacteria together with its host fungus may be considered as a fully functioning holobiont, where all parties perform certain tasks. However, further investigations on fungal-bacterial interactions will be essential for gaining a deeper understanding about their role in different environments.