Pavel Vejl

The contribution to the epidemiology of gastrointestinal nematodes of sheep with special focus on the survival of infective larvae in winter conditions

Tracer tests conducted over a 3-year period were aimed at measuring the level and species nematode composition of survival on pastures with a special focus on winter months. The survival of infective larvae in chilly conditions is not significantly affected by Trichostrongylus axei, Trichostrongylus colubriformis, Trichostrongylus vitrinus and Chabertia ovina. On the contrary, the number of Teladorsagia circumcincta and Nematodirus filicollis significantly increased in milder winter conditions. The results confirmed an epidemiological strategy of overwintering in the arrested stage for Teladorsagia circumcincta and Nematodirus filicollis; the epidemiological strategy of genus Trichostrongylus used both strategies—in particular the tolerance of free-living stages to cold conditions. Part of the population overwintered in the arrested stage as well.

Comparative morphological and molecular identification of Haemonchus species in sheep

SummaryA combined approach in the determination of Haemonchus nematodes from sheep was applied in this trial. Using selected morphological characters 90.2 % females and 84.2 % males of Haemonchus contortus and 9.8 % females and 15.8 % males of Haemonchus placei were identified. Although cluster analysis based on morphological identification clearly separated two Haemonchus species, H. contortus was exclusively detected in all specimens using restriction cleavage of the ITS-2 region with FspBI endonuclease as well as through the sequencing analysis. Because sheep from both farms have never had contact with other ruminants, and the farmers apply only closed flock turnover, we assume that only H. contortus mono-infection occurred on both farms. This opinion is also supported by molecular data. The most striking result of our study was the finding which indicates that the discriminant function is not able to accurately identify Haemonchus males at the species level.

Dealing with AFLP genotyping errors to reveal genetic structure in Plukenetia volubilis (Euphorbiaceae) in the Peruvian Amazon

An analysis of the population structure and genetic diversity for any organism often depends on one or more molecular marker techniques. Nonetheless, these techniques are not absolutely reliable because of various sources of errors arising during the genotyping process. Thus, a complex analysis of genotyping error was carried out with the AFLP method in 169 samples of the oil seed plant Plukenetia volubilis L. from small isolated subpopulations in the Peruvian Amazon. Samples were collected in nine localities from the region of San Martin. Analysis was done in eight datasets with a genotyping error from 0 to 5%. Using eleven primer combinations, 102 to 275 markers were obtained according to the dataset. It was found that it is only possible to obtain the most reliable and robust results through a multiple-level filtering process. Genotyping error and software set up influence both the estimation of population structure and genetic diversity, where in our case population number (K) varied between 2–9 depending on the dataset and statistical method used. Surprisingly, discrepancies in K number were caused more by statistical approaches than by genotyping errors themselves. However, for estimation of genetic diversity, the degree of genotyping error was critical because descriptive parameters (He, FST, PLP 5%) varied substantially (by at least 25%). Due to low gene flow, P. volubilis mostly consists of small isolated subpopulations (ΦPT = 0.252–0.323) with some degree of admixture given by socio-economic connectivity among the sites; a direct link between the genetic and geographic distances was not confirmed. The study illustrates the successful application of AFLP to infer genetic structure in non-model plants.

Reliable molecular differentiation of Trichuris ovis and Trichuris discolor from sheep ( Ovis orientalis aries ) and roe deer ( Capreolus capreolus ) and morphological characterisation of their females: morphology does not work sufficiently

The main aim of the study was to evaluate associations between morphological variability of Trichuris females from sheep and roe deer and their rDNA polymorphism in whipworm populations from the Czech Republic. The results introduced the use of new molecular markers based on the internal transcribed spacer (ITS)1-5.8S RNA-ITS2 region polymorphisms, as useful tools for the unambiguous differentiation of congeners Trichuris ovis and Trichuris discolor. These markers revealed both parasites in roe deer and in sheep; however, T. ovis females predominated in sheep while T. discolor females occurred mostly in roe deer. Additional analysis of ITS1-5.8 rRNA-ITS2 discovered the genetic uniformity of the analysed T. discolor but high haplotype variation of T. ovis. Simultaneously, molecularly designated female individuals of both species were categorised into four morphotypes (MT) on the basis of morphology of genital pore area. MT1 and MT4 (vulvar opening on everted vaginal appendage/on visible cuticular bulge) occurred only in T. ovis, MT2 (uneverted vagina—vulvar opening without any elevation) was identified only in T. discolor and MT3 (transient type of vulvar opening on a small swelling) was observed in both species. Statistical analysis of biometric data confirmed that morphology of vulva is not a reliable marker for the species determination. On the basis of the ITS1-5.8S RNA-ITS2 region variability, we carried out a phylogenetic analysis (maximum likelihood method, Hasegawa-Kishino-Yano model) which showed that T. ovis haplotypes from the Czech Republic and Ireland and T. discolor haplotypes from the Czech Republic, Spain, Iran and Japan are sister OTUs.

Phenotype and molecular diversity evaluation of some wild 2n Solanum species (super series Rotata)

Rotatamarkers. Totally 63 alleles of 20 cpSSR loci were detected i.e. 3.15 alleles on average per one microsatellite locus. Alleles ranged from two to six per locus. The highest polymorphism was detected in the locus ntcp9 and lowest were recorded having by two alleles in seven of loci. The average value of observed heterozygosity (H

Virulence and Mating Type of Phytophthora infestans Isolates in the Czech Republic

Abstract To evaluate the frequency and stability of the occurrence of P. infestans races and mating types in the Czech Republic, 338 monosporic isolates were collected from 31 sites in different potato-growing areas from 2012 to 2014 and in 2016. In total, 142 isolates were evaluated for virulence and race structure using the detached leaflet assay on Black’s differential set, supplemented with cultivar Sarpo Mira and somatic hybrid REG 46F. With the exception of virulence for resistance genes R9 and Rpi-blb-1, all virulence genes were detected among isolates, with a predominance of genes R1, R3, R7, R10, and R11. Most isolates were virulent to five or more R-genes, with a mean virulence complexity of 7.1. Among the 38 races detected, the most commonly occurring races were 1.2.3.4.6.7.10.11 and 1.2.3.4.7.10.11. Of the 338 isolates tested by the pairing test and the cleaved amplified polymorphism sequence (CAPS) marker, 40% were of the A1 mating type and 60% were of the A2 mating type, with an A1 : A2 isolate ratio demonstrating the predominance of the A2 mating type each year of the survey.

Evaluation of variations in plastid DNA non-coding regions in selected species of the genus Solanum

Sedláková V., Sedlák P., Zeka D., Domkářová J., Doležal P., Vejl P. (2017): Evaluation of variations in plastid DNA noncoding regions in selected species of the genus Solanum. Czech J. Genet. Plant Breed., 53: 127−131. The diversity of three non-coding plastid DNA loci (trnL/trnF spacer, trnV/16SrRNA spacer, trnL/trnL intron) was assessed in 16 Solanum L. species (135 individuals). Polymorphisms were detected by denaturing gradient gel electrophoresis (DGGE) and verified by direct sequencing. No intraspecific diversity and only poor interspecific diversity was detected. Unique S. mochiquense Ochoa specific length polymorphism at the trnL/trnL locus represented by duplication of an 18 bp segment was discovered. The detected DGGE interspecific trnL/trnF locus polymorphism did not specifically associate with single point mutations in the sequence confirmed by sequencing. The DGGE method was found to be a simple and cheap pre-exploring tool for mutation detection in compared DNA regions. Some identified polymorphisms can be used in the management of genetic resources.