Biologická ochrana proti patogenním houbám: budou hrát mykoviry důležitou úlohu?

In the past few years, huge economic and environmental losses have resulted by fungal pathogens in agriculture and food production worldwide. Fungal toxins also pose a threat for food production and animal health. In the last decade, the site-specific fungicides has been used in plant protection, providing highly efficient protection against phytopathogens. However, the use of pesticides boosted problems with resistance in the targeted organisms and increased negative environmental impact of insecticides, herbicides and fungicides. Therefore, new methods are needed to control resistant populations of plant pathogens, including fungi. Mycoviruses are fungal viruses, i.e. viruses infecting fungi. Some mycoviruses affect the growth and virulence of the host fungus and may prevent successful infection of plant host. They have potential to reduce phytopathogens. In this review, the successful examples how mycoviruses alter hypovirulence in well-known phytopathogens are discussed. Mycoviruses could be useful as a one of new next generation pest-control products.Houbové patogeny způsobují na zemědělských plodinách celosvětově velké ekonomické ztráty. V posledních několika desítkách let se úspěšně používala celá řada fungicidů, které omezovaly vliv houbových infekcí na pěstované plodiny, ovoce, zeleninu a okrasné rostliny. Negativním jevem spojeným s masivním používáním fungicidům je, že celá řada fytopatogenů získala rezistenci k chemickým přípravkům, nehledě na dopad používání pesticidů na necílové organizmy a životní prostředí. Proto v poslední době sílí snaha o nahrazení chemických prostředků na ochranu rostlin prostředky šetrnějšími k životnímu prostředí a lidskému zdraví. Jedním z těchto agens jsou mykoviry. Mykoviry jsou viry, které infikují houby, včetně houbových patogenů. Byla popsána celá řada mykovirů, které negativně ovlivňují virulenci a růst houbových hostitelů, a tím zabraňují k šíření infekce v hostitelské rostlině. Z tohoto pohledu by mohl výzkum mykovirů a jejich použití v ochraně rostlin přinést do budoucna významné výsledky

UTILIZATION OF DNA MARKERS BASED ON MICROSATELLITE POLYMORPHISM FOR IDENTIFICATION OF POTATO VARIETIES CULTIVATED IN THE CZECH REPUBLIC

In the year 2007, there were one hundred and seventy-eight potato varieties enlisted in the Czech list of registered potato varieties. The classical morphometric approach to characterization is not effective for such a number of varieties especially for identification at the level of tubers. The needfulness of variety identification at the level of tubers is important mainly for trade aspect. The Czech law no.110/1997 Sb. about the food-stuff and tobacco products and the consequential ordinance (MZe č. 332 / 1997 Sb.) require guarantee of variety declaration in commercial relation for table potato. In this study we analyzed twenty potato varieties (Solanum tuberosum L.) cultivated in the Czech Republic. Every variety was represented by four independent replicates. This set of samples was analyzed by methods of PCR-SSR (Simple Sequence Repeats) and PCR-ISSR (Inter Simple Sequence Repeats). We discovered that both of tested methods afford sufficient polymorphism for variety identification, but the method of PCR-ISSR is not utilizable, because we observed the variability within variety. For outright identification of the whole set of potato varieties cultivated in the Czech Republic we recommend to use SSR, AFLP and retrotransposene-based markers as well as morphological markers

Genetic Variability of US and Czech Phalaris Arundinacea L. Wild and Cultivated Populations

The spread of invasive plant species in natural habitats has become a worldwide problem with negative impacts. Phalaris arundinacea, an important forage and ornamental crop, is widespread worldwide. In recent years there has been a massive spread of P. arundinacea across North America and Canada. Production of Phalaris seed as a forage crop occurs in northern Minnesota; seeds are sold throughout the world, particularly in central Europe. We tested genetic similarities and differences between populations in the US (Minnesota) and the Czech Republic using ISSRs to determine potential gene flow for this forage crop. The cultivated forage and wild genotypes were dispersed into two groups that overlapped. At least four sets of wild US genotypes are dissimilar to European counterparts and potentially native to N. America. Future work to prove the ancestry of each accession will be necessary. Nonetheless, the sale of forage cultivars related to or derived from European types causes genetic mixing with N. American types. Part of this intercontinental gene flow is exacerbated by the production of Phalaris forage seed in Minnesota. The implications of these findings for management of invasive crops native to both continents are significant for forage producers, managers, and breeders

ANALYSIS OF SEQUENCE POLYMORPHISM OF SCR CLASS I AND II ALLELES AND STUDY REGULATION OF THEIR EXPRESSION

Self-incompatibility (AI) is a widespread mechanism used by flowering plants to prevent inbreeding depression and helps create and maintain genetic diversity within a species. Oilseed rape (Brassica napus L.) and especially its modern varieties are characterized by high level of self-fertility. In an effort to increase the production current breeding is focused on the production of inbred lines for making the F1 hybrids and the self-incompatibility can be an interesting tool for production self- sterile lines. In Brassica napus, we found two recessive alleles of a gene SCR II. Different expression of both alleles does not correspond to phenotypic manifestation of self-incompatibility and we can assume that it is prevailed by repressor gene that does not lie on the S-locus. This is also reason, why the SCR gene cannot serve as a molecular marker of self-incompatibility in Brassica napus, although many authors believe that this gene is essential in AI reaction. Brassica napus belong to plants with complex genetic constitution, is composed by two genomes, A and C, which give the possibility of different interactions and makes it difficult to study compared with diploid B. rapa and B. oleracea. In further study it is therefore important to focus on the interactions between genes SCR, SRK and SLG, and their influence on others, such as supressor gene systems

ANALYSIS OF SEQUENCE POLYMORPHISM OF SCR CLASS I AND II ALLELES AND STUDY REGULATION OF THEIR EXPRESSION

Self-incompatibility (AI) is a widespread mechanism used by flowering plants to prevent inbreeding depression and helps create and maintain genetic diversity within a species. Oilseed rape (Brassica napus L.) and especially its modern varieties are characterized by high level of self-fertility. In an effort to increase the production current breeding is focused on the production of inbred lines for making the F1 hybrids and the self-incompatibility can be an interesting tool for production self- sterile lines. In Brassica napus, we found two recessive alleles of a gene SCR II. Different expression of both alleles does not correspond to phenotypic manifestation of self-incompatibility and we can assume that it is prevailed by repressor gene that does not lie on the S-locus. This is also reason, why the SCR gene cannot serve as a molecular marker of self-incompatibility in Brassica napus, although many authors believe that this gene is essential in AI reaction. Brassica napus belong to plants with complex genetic constitution, is composed by two genomes, A and C, which give the possibility of different interactions and makes it difficult to study compared with diploid B. rapa and B. oleracea. In further study it is therefore important to focus on the interactions between genes SCR, SRK and SLG, and their influence on others, such as supressor gene systems

Plasma Technology in Food Industry: mini-review

Plasma treatment is an interesting technology with many potential applications in industry. At present, more and more often we encounter papers that deal with utilization of plasma technology in food industry. This mini-review provides an overview of the latest developments in this area. At the beginning the principles of plasma interaction with solid surfaces are shortly discussed. The next chapters are focused on sterilization of food from bacteria and fungi. The infl uence of plasma treatment on the food quality and nutritional parameters is discussed in last section

Minority cytotypes in European populations of the Gymnadenia conopsea complex (Orchidaceae) greatly increase intraspecific and intrapopulation diversity

Background and Aims Patterns of ploidy variation among and within populations can provide valuable insights into the evolutionary mechanisms shaping the dynamics of plant systems showing ploidy diversity. Whereas data on majority ploidies are, by definition, often sufficiently extensive, much less is known about the incidence and evolutionary role of minority cytotypes. Methods Ploidy and proportions of endoreplicated genome were determined using DAPI (4',6-diamidino-2-phenylindole) flow cytometry in 6150 Gymnadenia plants (fragrant orchids) collected from 141 populations in 17 European countries. All widely recognized European species, and several taxa of less certain taxonomic status were sampled within Gymnadenia conopsea sensu lato. Key Results Most Gymnadenia populations were taxonomically and/or ploidy heterogeneous. Two majority (2x and 4x) and three minority (3x, 5x and 6x) cytotypes were identified. Evolution largely proceeded at the diploid level, whereas tetraploids were much more geographically and taxonomically restricted. Although minority ploidies constituted <2 % of the individuals sampled, they were found in 35 % of populations across the entire area investigated. The amount of nuclear DNA, together with the level of progressively partial endoreplication, separated all Gymnadenia species currently widely recognized in Europe. Conclusions Despite their low frequency, minority cytotypes substantially increase intraspecific and intrapopulation ploidy diversity estimates for fragrant orchids. The cytogenetic structure of Gymnadenia populations is remarkably dynamic and shaped by multiple evolutionary mechanisms, including both the ongoing production of unreduced gametes and heteroploid hybridization. Overall, it is likely that the level of ploidy heterogeneity experienced by most plant species/populations is currently underestimated; intensive sampling is necessary to obtain a holistic pictur

Comparison of the effect of additives during Gliding Arc plasma treatment on the germination of bunt spores and growth characteristics of wheat

The gliding arc cold plasma treatment of wheat seeds is an alternative to chemical seed dressing, but this treatment is not very effective. This study was focused on testing the addition of salt, water and nitrogenous compounds during plasma treatment to increase the efficiency of the plasma seed treatment. The additives were not supplied in the gaseous state, as usual, but in an aqueous solution by spraying under a plasma nozzle during the treatment. The phytosanitary effect of the plasma treatment was evaluated based on the germination of Tilletia caries spores from artificially infected seeds on water agar. The viability of the seeds, growth and yield characteristics of the plasma-treated seeds were evaluated in the laboratory, greenhouse and even in field experiments with the primary goal of reducing spore vitality. The germination of T. caries spores was mostly limited to the variant with the addition of water during plasma treatment, where spore germination reached only 32.7% of the control variant while maintaining sufficient growth properties. The experiment demonstrated the suitability of using the addition of various substances during plasma treatment in the form of aqueous solutions and increasing the effectiveness of this treatment

Development of Real-Time and Colorimetric Loop Mediated Isothermal Amplification Assay for Detection of Xanthomonas gardneri

Xanthomonas gardneri is one of the causal agents of bacterial spot (BS), an economically important bacterial disease of tomato and pepper. Field-deployable and portable loop-mediated isothermal amplification (LAMP)-based instruments provide rapid and sensitive detection of plant pathogens. In order to rapidly and accurately identify and differentiate X. gardneri from other BS-causing Xanthomonas spp., we optimized a new real-time monitoring LAMP-based method targeting the X. gardneri-specific hrpB gene. Specificity and sensitivity of real-time and colorimetric LAMP assays were tested on the complex of bacterial strains pathogenic to tomato and pepper and on plants infected by the pathogen. The assay detection limit was 1 pg/&mu;L of genomic DNA with an assay duration of only 30 min. The use of portable and handheld instruments allows for fast analysis, reducing the diagnosis time, and can contribute to proper disease management and control of X. gardneri. Due to the high efficiency of this method, we suggest its use as a standard diagnostic tool during phytosanitary controls

VYUŽITÍ DNA MARKERŮ ZALOŽENÝCH NA POLYMORFISMU MIKROSATELITŮ PRO IDENTIFIKACI ODRŮD BRAMBOR PĚSTOVANÝCH V ČR

In the year 2007, there were one hundred and seventy-eight potato varieties enlisted in the Czech list of registered potato varieties. The classical morphometric approach to characterization is not effective for such a number of varieties especially for identification at the level of tubers. The needfulness of variety identification at the level of tubers is important mainly for trade aspect. The Czech law no.110/1997 Sb. about the food-stuff and tobacco products and the consequential ordinance (MZe č. 332 / 1997 Sb.) require guarantee of variety declaration in commercial relation for table potato. In this study we analyzed twenty potato varieties (Solanum tuberosum L.) cultivated in the Czech Republic. Every variety was represented by four independent replicates. This set of samples was analyzed by methods of PCR-SSR (Simple Sequence Repeats) and PCR-ISSR (Inter Simple Sequence Repeats). We discovered that both of tested methods afford sufficient polymorphism for variety identification, but the method of PCR-ISSR is not utilizable, because we observed the variability within variety. For outright identification of the whole set of potato varieties cultivated in the Czech Republic we recommend to use SSR, AFLP and retrotransposene-based markers as well as morphological markers.V současné době je v České republice registrováno 178 odrůd brambor (stav roku 2007). Klasická morfometrická charakterizace odrůd přestává být v tomto objemu registrovaných odrůd účinná, obzvláště na úrovni hlíz. Potřeba identifikovat konkrétní odrůdu na úrovni hlíz je přitom nejdůležitější, hlavně z obchodního hlediska. Platný zákon č. 110 / 1997 Sb. o potravinách a tabákových výrobcích a vyhláška na něj navazující (Vyhláška MZe č. 332 / 1997 Sb.) vyžadují u konzumních brambor garanci odrůdové deklarace při obchodním styku. Pro studii bylo vybráno 20 odrůd brambor (Solanum tuberosum L.) pěstovaných v ČR. Každá odrůda byla zastoupena čtyřmi nezávislými opakováními. Tento soubor byl analyzován metodami SSR (Simple Sequence Repeats) a ISSR (Inter Simple Sequence Repeats). Zjistili jsme, ze obě analýzy založené na polymorfismu mikrosatelitů poskytují dostatečnou variabilitu pro identifikaci odrůd, ale metoda ISSR se nejeví jako vhodná z důvodu zjištění její nestability. Pro jednoznačnou identifikaci celého spektra odrůd brambor pěstovaných v ČR doporučujeme sestavení setu markerů, který by zahrnoval více markerovacích systémů morfologických i molekulárních (SSR, AFLP a markery založené na retrotranspozonech)