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The aim of the thesis was focused on assessing the significance of the impact of habitat on the occurrence of the common scab of potatoes. In this context, following factors were evaluated: degree and extent of infestation tubers with common scab, effect of the habitat, impact of the variety, vintage influence, the influence of fertilization with nitrogen and sulfur influence seed treatment, starch content, tuber yield, the proportion of tubers over 40 mm. The review of literature of thesis includes chapters regarding the origin of potato, potato and morphological characteristics of its growth, consumer potatoes and factors that affect the quality and yield. It mentions measures against diseases and pests. The last section is devoted to common scab of potato. The practical part deals with evaluating the impact of habitat on the incidence of common scab of potatoes. The attempt was based on the habitat with the occurrence of common scab and habitats without occurrence of common scab in Vyklantice. The results were processed in program Statistica, version 12.0. (StatSoft) function of multifactor and one-way analysis of variance (ANOVA). At the habitat with higher pH and KVK higher incidence of common scab was recorded. It confirmed the impact of resistance of variety on the incidence of common scab. It was not confirmed statistically significant dependence on fertilizer nitrogen fertilizer LAV and seed treatment tubers with Trichoderma strains. It confirmed a statistically significant dependence on the incidence of common scab on fertilization with SulfoGranulat.

The diploma thesis is focussed on understanding relationships between soil chemical characteristics, actinobacterial communities of agricultural field soils and occurrence of potato common scab, a disease caused by members of the genus Streptomyces. The aim of monitoring study, on thirty-three sites covering main potato- growing regions in the Czech Republic, was to find relationships suitable for prediction of common scab severity. The second part of the thesis compared actinobacterial communities and incidence of Streptomyces harboring a pathogenic determinant, gene txtA (gene of biosynthetic pathway of phytotoxin thaxtomin A), in soils differing in occurrence of common scab. In the screening study, analysis of terminal restriction fragment length polymorphism (T-RFLP) was employed to compare composition of soil actinobacterial communities. Real-time PCR was used to quantify total actinobacteria and streptomycetes harboring txtA gene in soils differing in scab incidence. The screening study revealed negative correlations between the scab severity and (i) available phosphorus in soil and (ii) diversity of actinobaterial community. The results were used to design a model for scab prediction. A qPCR analysis showed difference in numbers of total actinobacteria and the strains harboring txtA gene in...

This diploma thesis focused on screening for bacterial pathogens and antagonists suppressing common scab mainly caused by Streptomyces scabiei. Common scab affects some agricultural crops causing significant economical losses. Bacterial strains, mostly streptomycetes, were isolated from potato rhizosphere because they belong to most important producents of secondary metabolites and the causative agents of the disease are also members of this genus. The isolated bacteria were characterised by PCR amplification and sequencing of 16S rRNA gene to reveal their phylogenetic relationships. The ability of isolated strains to suppress growth of Streptomyces scabiei was tested by a simple co-cultivation experiment. The strains were tested by PCR for presence of specific genes for biosynthesis of thaxtomin A, a common virulence factor found in all described pathogens causing symptoms of this disease on the surface of affected tubers. Genes for synthesis of thaxtomin belong to pathogenicity island. Standard of phytotoxin thaxtomin A was used to optimize its analysis by mass spectroscopy for further in vivo and in vitro experiments. Phylogenetic analysis of strains harboring one of the genes necessary for thaxtomin A biosynthesis supported the hypothesis of sharing the pathogenicity island by horizontal gene...

This bachelor thesis is focused on searching for secondary metabolite producers suppressing Streptomyces scabies (synonym scabiei), which is a causative agent of common potato scab affecting some species of agricultural crops. By the 16S rRNA gene sequencing strains of bacteria from potato rhizosphere were identified and strains effectively suppressing Streptomyces scabies were determined by a simple cultivation test. The work on this project will continue by focusing on identification of those secondary metabolites by HPLC.