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  • Overview of the evolutionary history and the role in citric acid production of alternative oxidase
    83-88
    Views:
    125

    All organisms are exposed to countless environmental effects, which influence in a disadvantageous way their life processes. They continuously adapt to the changing conditions and respond to the stress impacts by defence mechanisms. Through different signal transduction pathways they are able to increase or decrease the expression of their genes and consequently modify their metabolic processes. My interest focuses on alternative oxidase (AOX) enzyme whose expression is often increased under biotic and abiotic stress. The so far proven and putative functions of the AOX play a role in the ability of organisms to adapt to different conditions, such as heavy metals accumulation, pathogenic infection, oxidative stress and lack of oxygen or nutrients.

    AOX is a member of the di-iron carboxylate protein family. Members of the di-iron carboxylate protein family are present in all kingdoms of life. They are considered to have ancient origin. It is believed that their sulfide-resistant and oxygen-reducing ability played a role in the survival of organisms during the transition between the anaerobic and the aerobic world. It is assumed that the AOX arose in eukaryotes through a primary endosymbiotic event, and this event made possible the development of mitochondria. Afterwords, vertical inheritance, and secondary and tertiary endosimbiotic events led to its spread among eukaryotes. It is assumed that bacteria obtained AOX by horizontal gene transfer from plants.

    AOX-catalyzed alternative respiration plays an important role in the operation of energy-producing and biosynthesizing system of microorganisms. In these cases, the regeneration of reduced cofactors is an essential condition, and therefore may be rate-limiting for biotechnological processes, including the citric acid production.

  • Occurrence of woolly cupgrass (Eriochloa villosa /Thunb./ Kunth) in Hajdú-Bihar county, Hungary
    119-123
    Views:
    84

    Woolly cupgrass (Eriochloa villosa /Thunb./ Kunth) is native to East Asia, it spreads in several parts of the World and causes difficulties in plant protection, especially in maize. Difficulties in control of Eriochloa villosa originated from several reasons: seeds continue to germinate later in the season, significant part of seeds emerges from a deep layer of the soil, and the species is less susceptible to some herbicides applied to maize than other annual grass weeds.
    The first report on the occurrence of woolly cupgrass in Hungary was published in 2008, and it reported about the appearance of this species near to Gesztely village (Borsod-Abaúj-Zemplén county), however, no information has been added about spread of the weed in Hungary until now.
    A significant population was discovered next to Debrecen (Hajdú-Bihar county) in summer, 2011, and then weed associations were examined in maize, sunflower and stubble-fields on several km2 in the area to estimate the Eriochloa villosa infection. The weed species was found on every maize field bordering with a ground cover of 0.5-4%. Woolly cupgrass occurred inside of the 50% of maize fields, and reached a ground cover of 76% in case of most infected area, in addition it was found in sunflower and stubble-fields.
    The spread of woolly cupgrass is expected in this area, which requires the consideration of this species in the planning of weed management technologies.

  • A dual infection of two microscopic fungi on common milkweed (Asclepias syriaca) in Hajdúság region (East-Hungary)
    189-195
    Views:
    164

    Common milkweed (Asclepias syriaca L.) is one of the most noxious and invasive weed species in Hungary. A. syriaca invades arable lands, horticultural and forestry plantations, natural and semi-natural habitats too. In cases of field crops it can cause considerable yield losses mostly in maize (2–10%), soybean (12–32%) and sorghum (4–29%), but only with high rate of coverage. It can also increase these problems that the common milkweed can be serve as reservoir and host for viruses, other pathogens and pests.
    Because of the importance of common milkweed and in spite of demand to develop effective biological control, until now has not been developed a proper control program against A. syriaca. The aim of our research was to identify the necrotrophic fungal pathogens, which were involved in notable disease occurrence on this weed in different parts of Hajdúság region of Eastern-Hungary in 2016.
    To the isolation of fungi from leaves and their identification were based on morphological colony characters on potato dextrose agar (PDA) and Sabouraud dextrose agar (SDA). To the description of conidia features were used PDA for Alternaria and synthetic low-nutrient agar (SNA) for Fusarium species, respectively. The examination of axenic cultures revealed that the fungi isolated from the leaves of common milkweed were Fusarium sporotrichioides and Alternaria alternata.

  • Anaerobe degradation of maize infected by Fusarium graminearum
    57-61
    Views:
    123

    Last year intense rainfalls and moisture conditions were beneficial for the Fusarium sp. in Hungary. Fusarium strains decrease cereal quality (for example maize), furthermore may cause yield loss. Due to the toxin production, the fungi have a dangerous animal and human pathogen effect (Placinta et al., 1999).The effects of the Fusarium infection and its mycotoxin production haven’t been perfectly eliminated. Fusariumgraminearum
    is the most common agricultural pathogen in Hungary. The utilization of infected maize as an alternative biogas raw material may be an efficient and environmentally friendly disposal method. In this case, Fusarium-, and mycotoxin-content of the maize have to be analyzed as well as the impact of these factors’ on the biogas production process. Our experience was based on the raw material basis of a biogas plant. Different amount of Fusarium free and infected maize grits have been added to the regular raw material mixture. The detection of Fusarium fungi has been analyzed
    in experimental digesters throughout the different stages of mesophilic digestion. In the biogas liquid end product the Fusarium was detected by breeding and by microscope. According to our results, the Fusarium sp. was not detectable in the liquid end product after 30 days.

  • The effect of location on the incidence of brown rot blossom and shoot blight infection on apricot
    89-91
    Views:
    98

    The aim of our study was to assess the incidence of brown rot blossom and shoot blight and caused by Monilinia laxa. Assessments of incidence were made on cv. Bergeron (susceptible to brown rot) in a flatland and a hilly growing area (at Cegléd and Gönc, respectively). In 2004, when spring and summer weather conditions were wet and cold, incidence reached 95 % for blossom blight and 33 % for shoot blight in the untreated plots. Blossom blight incidence was 1.5-2 times higher in the flatland area compared to the hilly growing area. During the blooming period of apricot, two (at flower bud stage and at full bloom) and three (at flower bud stage, at full bloom and at petal fall) fungicide applications were necessary for the successful control at Gönc and Cegléd, respectively. The difference between the two orchards was due to the fact that blooming started one week later in the hilly region (at Gönc) than in the flatland region (at Cegléd), therefore, the critical weather period coincided with blooming in the orchard in the hilly region only partially.

  • The role of disease resistance in the registration of crop varieties in Hungary
    27-29
    Views:
    126

    Variety testing including disease resistance test of the major crops has been carrying out since the 1960’s in Hungary. Testing for resistance of the new candidate varieties is performed in the so-called VCU (Value for Cultivation and Use) trials under natural infection and in special small-plot or micro-plot trials using different disease provocative methods. Disease resistance, especially those of multiple and horizontal-type (race non-specific, partial or durable) resistances, has recently become a key limiting factor in the state variety registration. The role of disease resistance in the decision-making process of variety registration is demonstrated on the examples of winter wheat and sunflower as two major field crops in Hungary.