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Comparative methods for studying adaptive traits of fungal symbionts
Veselská, Tereza ; Kolařík, Miroslav (advisor) ; Voigt, Kerstin (referee) ; Dvořák, Miloň (referee)
The kingdom Fungi encompasses an estimated 2.2 to 6.2 million species that occupy diverse environments, including aquatic, extremely dry, and hot or frosty habitats all over the world. To cope with adverse environmental conditions, fungi have developed numerous adaptations and life strategies, including symbiosis with other organisms, ranging from close, reciprocally beneficial (mutualistic) associations to severe pathogenic infestations. These interactions have an enormous impact on ecosystem functioning, with implications for agriculture and human health. For this reason, understanding the mechanisms enabling the successful development of fungal interactions is necessary for their efficient management. Recent advances in different 'omics' approaches have enabled us to compare species responses to the environment in a more complex way than before and to gain deeper insights into the adaptive mechanisms underlying specific life strategies. My thesis is divided into four main sections. In the first section, I sum up findings about adaptations of fungal symbionts of plants and animals. Then, I introduce two fungal genera, Geosmithia and Pseudogymnoascus, to which I applied comparative methods for tracking adaptive traits. The ecological diversity of the genus Geosmithia allows to trace adaptive...
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Molecular phylogeny of the genus Geosmithia
Korittová, Celie ; Kolařík, Miroslav (advisor) ; Tomšovský, Michal (referee)
The genus Geosmithia contains 11 described and several tens of undescribed species of fungi living nearly exclusively in galleries of subcorticolous insects, especially bark beetles. In this work, a phylogenetic analysis of the genus was made using DNA sequences of four protein-coding genes, namely TEF-1, RPB2, Mcm7 and Tsr1. The analysis has confirmed that ecological strategies of these fungi (such as association with conifers or broad leaved trees or symbiosis with ambrosia beetles) have evolved several times in this genus. 51 species are recognized based on the obtained phylogenetic tree according to Genealogical Concordance Phylogenetic Species Recognition. I have also tested utility of the above mentioned genes to serve as "barcode" for identification of closely related Geosmithia species.
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Evolutionary ecology of the genus Geosmithia
Veselská, Tereza ; Kolařík, Miroslav (advisor) ; Gryndler, Milan (referee)
7 Abstract The genus Geosmithia Pitt (Ascomycota: Hypocreales) belongs to fungi living in symbioses with bark beetles. Its original strategy is association with phloeophagous bark beetles (Coleoptera: Scolytinae). The Geosmithia shows strong affiliation to vector (bark beetles) worldwide and the spectrum of host plants is delimitated by niche of vector. The genus includes the specialists to family Pinaceae, but also the generalists with wide range of host plants mainly belonging to broad-leaved trees. G. morbida changed its ecology from saprotrophic to pathogenic way of life and causes decline of Junglans nigra in the USA. Characteristics which allow its pathogenesis are not known. Another derived strategy, which occurred at least twice independently, is association with the ambrosia beetles. The ambrosia beetles create galleries in xylem with low nutritive value, and thus they cultivate ambrosia fungus, on which they are entirely nutritively dependent. The ambrosia fungi share convergent phenotype which leads to large terminal conidia and to ability of yeast growth. This master thesis is focusing on study of the features, which are important for individual ecological groups: the specialists to family Pinaceae, the pathogene, the ambrosia fungi and the generalists. It is becoming apparent that the most...
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