In the present study, the determination and computer-assisted characterization of ribosomal DNA (rDNA) sequence data were performed to improve classification and diagnostics of nematodes of the genus Ditylenchus. Dot-plot analyses of the ITS1-5AE8S-ITS2 segments revealed the presence of short repeated DNA motifs localized in the ITS1 region of D. destructor, whilst no similar DNA repeats were identified in other members of the genus. Additionally, three-domain secondary structure models were inferred for ITS2 transcripts, providing a valuable resource for complex phylogenetic studies. Finally, alignment of the ITS-rDNA sequence data and subsequent oligonucleotide combinations trials led to the development of taxon-specific amplified regions. Together, this is the first report in which the three most common taxa of crop-parasitic nematodes of the genus Ditylenchus, namely D. dipsaci sensu stricto, Ditylenchus sp. B and D. destructor, have been simultaneously detected using a multiplex polymerase chain reaction (PCR)-based approach. This novel DNA technology is particularly valuable for the precise molecular diagnostics applicable to phytosanitary control and marker-assisted selection (MAS)-based plant breeding.

The epidemiology of potato late blight (Phytophthora infestans) was observed over the three-years with 110 potato varieties from various maturity groups treated or not treated with fungicides. The determined severity values were transformed into AUDPC coefficients characterizing rate of disease spreading across the crop in connection with varietal characteristics, fungicide application and year effects. The analysis of the pathogen population for the distribution of races virulent to usually used resistance genes indicated non-efficiency of these genes; resistance could only be increased by breeding for polygenically determined horizontal resistance. There were important yearly variations observed for the epidemiology of P. infestans. A correlation was detected between increasing AUDPC value and yield reduction in both fungicide treated and non-treated variants. AUDPC value of the treated variant is to a certain extent positively correlated with the value of the non-treated variant. However, particular interaction between potato genotype and applied fungicide program was shown, which could positively or negatively affect disease course in dependence on the variety.

Phoma stem canker (blackleg) is a disease of world-wide importance on oilseed rape (Brassica napus) and can cause serious losses for crops globally. The disease is caused by dothideomycetous fungus, Leptosphaeria maculans, which is highly virulent/aggressive. Cyclophilins (CYPs) and FK506-binding proteins (FKBPs) are ubiquitous proteins belonging to the peptidyl-prolyl cis/trans isomerase (PPIase) family. They are collectively referred to as immunophilins (IMMs). In the present study, IMM genes, CYP and FKBP in haploid strain v23.1.3 of L. maculans genome, were identified and classified. Twelve CYPs and five FKBPs were determined in total. Domain architecture analysis revealed the presence of a conserved cyclophilin-like domain (CLD) in the case of CYPs and FKBP_C in the case of FKBPs. Interestingly, IMMs in L. maculans also subgrouped into single domain (SD) and multidomain (MD) proteins. They were primarily found to be localized in cytoplasm, nuclei, and mitochondria. Homologous and orthologous gene pairs were also determined by comparison with the model organism Saccharomyces cerevisiae. Remarkably, IMMs of L. maculans contain shorter introns in comparison to exons. Moreover, CYPs, in contrast with FKBPs, contain few exons. However, two CYPs were determined as being intronless. The expression profile of IMMs in both mycelium and infected primary leaves of B. napus demonstrated their potential role during infection. Secondary structure analysis revealed the presence of atypical eight b strands and two a helices fold architecture. Gene ontology analysis of IMMs predicted their significant role in protein folding and PPIase activity. Taken together, our findings for the first time present new prospects of this highly conserved gene family in phytopathogenic fungus.

MAZÁKOVÁ J., TÁBORSKÝ V., ZOUHAR M., RYŠÁNEK P., HAUSVATER E., DOLEŽAL P. They were analysed for mating type using the conventional pairing assay and PCR markers; 107 isolates were of A1 and 92 of A2 mating type. No self-fertile isolate was found. Our study is the first report of the presence and distribution of the A2 mating type of P. infestans in the Czech Republic. The co-existence of the two mating types may enable the pathogen to reproduce sexually, thus enhancing the diversity of its population countrywide.

The northern root-knot nematode (Meloidogyne hapla) is a prominent root vegetable pest in the Czech Republic. Effects of several plant essences for M. hapla management on carrot (Daucus carota) were tested. The tested compounds included commercially available plant essences from Ocimum basilicum (sweet basil), Mentha arvensis (field mint), Tagetes erecta (Mexican marigold), and commercial product of neem seed (Azadirachta indica). Two further essences from Eugenia caryophyllata (clove) and Origanum majorana (marjoram) were obtained by distillation. Tests were conducted on container-grown carrots maintained under field conditions. The delivery method involved absorbing the tested essences in perlite particles placed in a substrate. The results showed a negative correlation between gall numbers of the carrots and treatment concentrations, especially for clove and majoram. Similar results were achieved when considering M. hapla egg numbers. Furthermore, the same treatments showed significant differences (P C 0.05) in fresh and dry root weights. Based on these results the management of M. hapla using plant essences seems to be possible, however, further research is desirable to determine the appropriate dosage needed for efficient and most appropriate delivery method of these substances under field conditions.