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Diversity, ecology, and biotechnological potential of yeasts associated with bark beetles
Havlíček, Václav ; Kolařík, Miroslav (advisor) ; Novotný, David (referee)
Bark beetles (Coleoptera; Scolytinae) attack woody plants, which is why they are considered pests from a human perspective. They owe their evolutionary success, among other factors, to numerous symbioses with microorganisms, with fungi playing a significant role. The mycobiome of bark beetles is dominated by yeasts, which, nevertheless, are widely overlooked. Intestinal yeasts not only from Ips typographus but also from other species of bark beetles have potential for future biotechnological applications. The aim of this study was to examine their diversity and physiological activities, which will help clarify their ecological role and biotechnological potential. Collections were conducted in the Czech Republic from larvae of the spruce bark beetle Ips typographus and from various species of subcortical insects in Kenya. Yeasts were identified and taxonomically classified based on rDNA sequencing. A total of 133 yeast strains belonging to 37 species were identified, including 9 species that could not be identified and belong to previously undescribed species and in two cases also genera. A total of 133 yeast strains belonging to 37 species were identified, including 9 species that could not be identified and belong to previously undescribed species and in two cases also genera. The most frequently...
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Natural enemies of the European spruce bark beetle \kur{Ips typographus}
BÁRTA, Jiří
Bark beetles (Scolitynae) are among the most important pests of forest stands, where they cause extensive damage, especially in spruce monocultures. Their negative effect is to attack the host tree, which is its source of food and at the same time provides them with space for reproduction. The bark beetle is able to have several generations per year under suitable temperature conditions. One of the most widespread is consi-dered to be the European spruce bark beetle Ips typographus. This species is able to search for weakened and abiotically damaged trees. Integrated Pest Management of forests includes several effective methods against bark beetles. The most used met-hods include the installation of feromone traps, traps trees and poisoned tripods. The European spruce bark beetle is in their population regulated by many natural enemies. From parasitoids such as Coeloides bostrichorum and Rhopalicus tutela and predators Thanasimus formicarius and Medetera spp. to pathogenic microorganisms such as entomopathogenic viruses, bacteria, protozoa, microsporidia and especially entomo-pathogenic fungi belonging to the order Hypocreales. The most important species is the fungus Beauveria bassiana, which has the greatest potential in the biological pro-tection of spruce stands.
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The role of microbial symbionts in the life cycle of Ips typographus
Havlíček, Václav ; Kolařík, Miroslav (advisor) ; Veselská, Tereza (referee)
Bark beetles (Coleoptera;Scolytinae) are usually considered as pests, because they attack trees in the protected and recreational forests and in the forests with economic importance. Their larvae develop under the bark, where it disturb the conductive tissues and affect the nutrient transport. Ips typographus attack Norway spruce (Picea abies). P. abies is an economic important woody plant. The life cycle of bark beetle is affected by its microbial symbionts in both positive and negative manner. Most of these organisms are facultative symbionts and they aren't completely depend on bark beetles. However, bark beetles are completely depend on its microbial symbionts. Symbiotic bacteria and fungus can be disseminated without bark beetles, but they are often spread by beetles. Microbial symbionts help overcome the defence mechanism of attacked trees, later they help with food digestion. Some fungi species can accumulate nitrogen in areas near the feeding chambers and improve ratio between carbon and nitrogen in plant tissue. Some bacteria are able to fix atmospheric nitrogen or use uric acid, helping with nitrogen recycling. Number of intestinal symbiont diversity increase in the course of host development. This symbionts are probably gained during feeding. The presence and prevalence of the...
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The Issue of Spruce Monocultures in Connection with Occurrence of Bark Beetles in the National Park Šumava with Application into Education
Kadeřávková, Lucie ; Skýbová, Jana (advisor) ; Andreska, Jan (referee)
The diploma thesis deals with the issues of the spruce monocultures in the relation to the incidence of the bark beetle (Ips typographus) in the Šumava National park. The aim of the thesis is not only to unify and arrange the information, but also find out the level of knowledge about this topic among the pupils of the ninth grade of the basic school. The work also shows the level of knowledge of the pupils about the related problems and what are their opinions and suggested solutions. The thesis is divided into the theoretical and practical part. The theoretical part consists of eight chapters, that are devoted to the history of the Šumava forests, pine tree monocultures with the closer focus on the Norway spruce (Picea abies), the differences among the "natural" and "economical" forest and to the uniqueness of the Boubín primeval forest. In one of the chapters we get information about the huriccane Kyrill and its effects on the Šumava forests and followed by the information about the bark beetle calamities and about the bark beetle on its own. The last two chapters are devoted the solution of the current situation in the Šumava forests and their future perspectives. The practical part of the thesis contains mainly of the questionnaire survey proceeded among the pupils of the ninth grade of the...
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Study of culturable anaerobic bacterial communities living in symbiosis with bark beetles; its isolation, taxonomy and biotechnical potential.
Fabryová, Anna ; Garcia-Fraile, Paula (advisor) ; Mrázek, Jakub (referee)
Microbial enzymes implicated in plant cell hydrolysis may have several potential aplications such as biomass degradation biocatalysts or with biofuel production. Bark beetles establish symbiosis with several microbial strains which play different roles benifitting the beetle, as the production of hydrolytic enzymes to degrade the ingested wood, the protection against mirobial antagonist or the detoxification of the environment. Fungal symbionts have been traditionally the best studied, but several recent research with bacterial symbionts of several bark beetle species show that bacterial also display important functions for the host. In this study, the bacterial communities of the bark beetle species Cryphalus piceae and Pithophtorus pithophtorus, collected in the Czech Republic from pine and fir trees, respectively, were isolated and 55 out of 89 samples were identified by 16S rRNA gene amplification and sequencing. Members of the genera Erwinia, Pantoea, Curtobacterium, Yersinia, Pseudomonas and Staphylococcus were detected. The isolates were object of study for their possible biotechnological potential in (ligno)cellulose materials degradation by screening several enzymes implicated in plant cell hydrolysis, as cellulases, xylanases, amylases, laccases, as well as their capability for colorant...
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Comparison of bark boring species composition on douglas-fir and pine
Košík, Kamil ; Pešková, Vítězslava (advisor) ; Šenfeld, Petr (referee)
This work deals a comparison the diversity of species of bark beetles on Douglas fir (Pseudotsuga menziesii Mirb./Franco) and Scots pine (Pinus sylvestris L.). On location the Green Shed in the Central Region of the Czechia were laid 24 traps, so that Douglas fir and Scots pine formed a couple. They were prepared two variants - trees up to 30 years and a trees of 40 - 60 years old. Evaluation took place after four sections in the relative distances. Research has shown that the both species of the trees were not broad spectrum of bark beetles. On Douglas fir it was only a Pityogenes chalcographus L., who was found in only one trap tree at the age of 30 years, and on the Scots pine trap tree was found only Tomicus piniperda L., but it was found in most traps.
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