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1.
RAZMNOŽEVANJE TIGRASTEGA KOMARJA (Aedes albopictus) V NOVI GORICI
Urban Česnik, 2016, undergraduate thesis

Abstract: Goriška regija z Novo Gorico je zaradi milega podnebja in prehodne lege ugodno okolje za tujerodne vrste, tako rastlinske kot živalske. V zadnjih letih je invazivna vrsta tigrastega komarja (Aedes albopictus Skuse, 1894) na tem območju naselila areal, v katerem se nemoteno razmnožuje in vzdržuje stalno populacijo. V diplomskem delu smo se odločili spremljati letno dinamiko pojavljanja jajčec in ličink komarjev na različnih lokacijah mestnega, primestnega in gozdnega okolja. S preverjanjem prisotnosti ličink tigrastega komarja na različnih lokacijah smo poskušali dobiti odgovor na to, kje se nahajajo za to vrsto ugodni mikrohabitati. Rezultati so bili pridobljeni s pomočjo pasti, s katerimi smo spremljali številčnost ličink v okolju. Ob zaključku smo preverili še razmerje med številom ličink avtohtonih vrst komarjev in ličink tigrastega komarja. Dobljene vrednosti smo primerjali med seboj, ugotavljali dinamiko razmnoževanja in določali območja, ki jih ta vrsta v večjem številu naseljuje. Iz raziskave smo ugotovili, da tigrasti komar na tem območju naseljuje predvsem urbane habitate, manj pa je zastopan v gozdovih. Začetek pojavljanja prvih ličink smo zabeležili v drugi polovici maja, njihovo število je strmo naraščalo do julija, ko smo raziskavo tudi zaključili. Največje število ličink na vseh vzorčnih mestih je pripadalo tigrastemu komarju, manj pa je bilo avtohtonih vrst komarjev. Med preučevanimi potencialnimi razmnoževalnimi habitati smo daleč največjo številčnost ličink tigrastega komarja zaznali v peskolovih.
Found in: osebi
Keywords: Nova Gorica, invazivne vrste, Aedes albopictus, ličinke tigrastega komarja, razmnoževanje, reprodukcijska dinamika
Published: 30.09.2016; Views: 3661; Downloads: 185
.pdf Fulltext (3,62 MB)

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Study of yeast biodiversity potential in the development of biological control agents against phytopathogenic fungi in viticulture
Lorena Butinar, Urban Česnik, Adesida Rowland, Melita Sternad Lemut, 2017, published scientific conference contribution abstract

Abstract: Despite public’s growing concerns for human health and environmental pollution, synthetic fungicides are still preferred and massively used for the protection of agricultural crop plants against fungal diseases. However, more and more research is focused on finding potential alternatives in the form of effective biological control agents. Although there are reports of yeast’s biocontrol activity, they are up to date poorly commercialized for such purposes. As the yeasts represent an important part of the grape microflora, competing with other microorganisms (including pathogens) for nutrients and space, we decided to examine the potential of autochthonous yeasts as "green" alternatives in fighting against phytopathogens such as Botrytis cinerea in viticulture. With this aim we tested biocontrol activity of various strains / species of indigenous wine yeasts that were isolated from the vineyard environment in Slovenia and cross-border Italy. The yeasts were tested for the presence of siderophores, hydrolytic enzymes (chitinase, β-glucosidase and β-glucanase) and sensitivity to fungicides (copper, iprodion, cyprodinil + fludioxonil combination). The tests of phytopathogenic fungi growth inhibition in the presence of antagonistic yeast were also performed. The double Petri dish test was used to verify the inhibition of conidia germination by the formation of antifungal volatile organic compounds (VOC), synthetized by the antagonistic yeasts. The presence of hydrolytic enzymes was confirmed in many wine yeasts, particularly in the strains of Hanseniaspora uvarum and Metschnikowia pulcherrima species and in some strains of the Pichia genus. Using a medium, based on natural diluted grape juice in a double Petri dish test, we found that yeasts of the Debaryomyces hansenii, Lachancea thermotolerans, P. kudriavzevii, Saccharomyces kudriavzevii, S. cerevisiae and Torulaspora delbrueckii species were able to inhibit the germination of fungal conidia at the expense of the VOC formation. However, none of the up to date tested yeasts formed siderophores. On the other hand, the yeasts were generally resistant to the tested fungicide concentrations, thus they could be used as potential biofungicides in the combination with chemical fungicides.
Found in: osebi
Keywords: yeasts, biocontrol, Botrytis cinerea, viticulture
Published: 08.11.2017; Views: 1355; Downloads: 0
.pdf Fulltext (10,33 MB)

4.
Prisotnost biokontrolne aktivnosti pri kvasovkah, osamljenih iz vinogradniškega okolja
Urban Česnik, 2019, master's thesis

Abstract: Opravili smo dve hitri molekularni tehniki za identifikacijo enoloških kvasovk, ki so bile izolirane iz vinogradov z ekološko in intergrirano pridelavo grozdja. Najprej smo določili 15 Saccharomyces kvasovk s pomočjo analize multipleks PCR med zbranimi 131 izolati, nato smo s pomočjo ribotipizacije ITS določili približno 98 kvasovk do nivoja vrste, ki so bile potrjene tudi s sekvenciranjem regije ITS. Določili smo 16 vrst vinskih kvasovk: Hanseniaspora uvarum, H. valbyensis, H. opuntiae / H. uvarum, Lachancea thermotolerans, Candida tropicalis, Candida sp. / Starmerella sp., Metschnikowia pulcherrima, Pichia kudriavzevii, P. terricola, P. kluyveri, Wickerhamomyces anomalus, Kodamaea ohmeri, S. bacillaris, Saccharomyces cerevisiae, Saturnispora diversa in Torulaspora delbrueckii. Ugotovili smo, da so najdene kvasovke običajne naseljevalke grozdne mikroflore ter da je način pridelave grozdja vplival na pojavljanje določenih vrst v obravnavanih vinogradih. Nadalje smo testirali kvasovke na tvorbo sideroforov, tvorbo protiglivnih hlapnih organskih spojin (HOS), hidrolitično aktivnost in toleranco kvasovk na fungicide, kot so baker, iprodion, fluazinam ter kombinacijo ciprodinil / fludioksonil. Za kvalitativno detekcijo hidrolitične aktivnosti smo uporabili presejalne teste na osnovi trdnega gojišča z dodanim hitinom ali β-D-glukozidi kot substratom in ugotovili, da je veliko testiranih kvasovk sposobnih proizvajati litične encime, ki bi lahko bili odgovorni za razgradnjo celičnih sten fitopatogenih gliv in potencialno sposobni proizvajati HOS s hidrolizo grozdnih glikozidov zaradi prisotnosti β-glukozidaz. Prav tako smo opazili, da so te encimske aktivnosti običajno odvisne od seva. Na splošno so kvasovke tudi tolerantne na testirane fungicide. Ugotovili smo tudi, da je odpornost biofungicidnih kvasovk na fungicide koristna lastnost za razvoj biofungicidov v prihodnosti pri aplikacijah v strategijah z zmanjšanim vnosom pesticidov.
Found in: osebi
Keywords: Kvasovka, biološki nadzor, fitopatogen, Botrytis cinerea, vinogradništvo
Published: 01.12.2019; Views: 413; Downloads: 18
.pdf Fulltext (1,57 MB)

5.
Facilitating green care improvements in viticulture
Paolo Sivilotti, Tjaša Jug, Urban Česnik, Adesida Rowland, Melita Sternad Lemut, Lorena Butinar, Urška Vrhovšek, 2019, published scientific conference contribution

Abstract: The growing demand of consumers for environment-friendly and safe food products already forced many winemakers to restrict the application of synthetic fungicides to earlier season, trying to reduce the risk of residues being detected in wines. Main risk for infection by B. cinerea, however, occurs later in the season. To support an improvement in whole-season B. cinerea green care, the potential of yeasts as biocontrol agent (PBA) was studied. Selected yeasts were tested for their antifungal activities. Furthermore, a field experiment in Pinot noir and Pinot gris vineyards was designed to study different combinations of optimized canopy microclimate manipulation (CMM) techniques and PBA application. In experimental conditions, PBA's ability to maintain appropriate population density for disease prevention was observed. Grape and wine quality parameters were evaluated. Analytical approach of metabolomics was applied to upgrade the understanding of potentially induced changes in plant metabolism. Based on yeasts testing results, biocontrol yeast P. guilliermondii ZIM 624 was selected and after its field application, we were able to detect its suitable density on grapes until harvest. In case of early defoliation for both varieties smaller grape compactness was confirmed together with lower yield. Among grape basic quality parameters, optimized techniques showed positive effect on sugar content, but unexpectedly, in the treatments with biocontrol yeasts the trends toward higher acidity were noticed in Pinot gris. CMM and PBA introduction indicated some effects on grapevine biosynthetic behaviour but the differences in content of these metabolites compared to control were poorly detected in final wines with exception of mainly some flavonols, stilbenes and flavan-3-ols (and consequently total phenolic content).
Found in: osebi
Keywords: sustainable viticulture, Botrytis cinerea, yeasts, biocontrol, canopy microclimate manipulation, metabolomics, grapevine metabolites
Published: 28.02.2020; Views: 294; Downloads: 0
.pdf Fulltext (7,85 MB)

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