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Evolution, diversity, and ecology of the genus Geosmithia with emphasis on G. morbida.
M. KOLARIK (1). (1) Institute of Microbiology of the Academy of Sciences of the Czech Republic, Prague, Czech Republic

Bark beetles are associated with diverse fungal symbionts. One of these fungi, with poorly known biology belong to the genus <i>Geosmithia</i> (Ascomycota: Hypocreales). The current knowledge is based on samples from western Palearctic, USA and several other regions. 50 species of the genus (22 published, 11 formally described) were found until now. <i>Geosmithia</i> spp. are typically associated with phloeophagous bark beetles, bostrichids and weevils, and over of 90% from the screened insects species were found to be obligate or facultative vectors. A derived ecological strategy, found in three <i>Geosmithia</i> spp., represents association with ambrosia beetles, where they act as primary ambrosia fungi. Several species occur on alternative substrates or can live as endophytes of healthy trees. One species, <i>G. morbida</i>, was proven to be a pathogenic fungus causing tissue necroses on walnuts. <i>Geosmithia</i> community pattern and presence of primary ambrosia fungi suggest the long-term and stable association between <i>Geosmithia</i> and bark beetles. <i>G. morbida</i> belongs to clade of hardwood-associated species. Major enzymatic activities, utilization of C, N, P, S sources (BIOLOG microarrays), secondary metabolites and antimicrobial activities of <i>G. morbida</i> are presented. Physiological fingerprinting places <i>G. morbida</i> among strict specialists confirming its specificity to a single host and long term co-evolution.<p><p>Keywords:

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