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Abstract: Grapevines (Vitis vinifera L.) represent one of the most important crops in the world in terms of both production and economic importance. Grapevines are exposed to many types of abiotic stresses (e.g., drought, flooding, low and high temperature, salinity) and biotic stresses (e.g., viruses, bacteria, phytoplasma, fungal disease) during their life-cycle. Therefore, grapevines elicit the appropriate defence mechanisms. In the first part of this study, we monitored the occurrence of Grapevine fanleaf virus (GFLV) infection, which causes progressive decline of infected grapevines and lowers their yield. Grapevines were also tested for the presence of other viruses important for grapevines: Arabis mosaic virus (ArMV), Grapevine leafroll associated virus (GLRaV)-1, -2, -3, -4, -9, Grapevine virus A (GVA), Grapevine fleck virus (GFkV) in this study; and by Cigoj (2015): Grapevine virus B (GVB), Tomato black ring virus (TBRV), Grapevine chrome mosaic virus (GCMV), Tomato ringspot virus (ToRSV), Raspberry ringspot virus (RpRSV), Strawberry latent ringspot virus (SLRSV), and Tobacco ringspot virus (TRSV). Using ELISA, the presence of the following grapevine viruses were detected: GFLV, (GFkV), (GVA), and Grapevine leafroll associated viruses- 1, -2, -3,. A wide range of GFLV symptoms caused by grapevine fanleaf disease in naturally infected vineyards were observed, including leaf, shoot and cluster malformations and leaf yellowing. GFLV is disseminated by its biological vector X. index, and through vegetative propagation of virus-infected material. The spread of GFLV in the vineyards was investigated here. We constructed a spatio-temporal study of the GFLV titres during the seasons and throughout the grapevine, for its distribution in different grapevine organs through the season. This study shows that young leaves have high virus titres through the whole vegetative period, while mature leaves, tendrils and flower/ berry clusters only have high titres at the beginning of the vegetative period. The seeds retain high virus titres after berry colouring. Phloem scrapings were shown to contain lower virus titres during the vegetative period, with an increase outside and at the beginning of the vegetative period. In flower/ berry clusters, mature leaves and tendrils, the GFLV titres decrease significantly over the vegetative period. Additionally, different GFLV titres were shown in five different cultivars, and different combinations of mixed infections with other grapevine viruses influenced the GFLV titre differently. Finally, correlation between the magnitude of symptom appearance and GFLV titres was analysed. Grapevines adapt to abiotic stresses and biotic stresses by the expression of a wide range of stress-responsive genes, which are thought to have key roles in stress tolerance and survival. SWP of the infected grapevines through the season was lower than SWP measured for healthy grapevines. For both seasons, there were significant differences in SWP measurements between healthy and GFLV-infected grapevines of ‘Schioppettino’ trained using the single Guyot training system. SWP and RHC of the GFLV-infected grapevines were reduced compared to the healthy controls. The water deficit triggered the production of ABA, which induced the expression of the stress-related gene RD22. Additionally, this study shows that the WRKY gene that is involved in the ABA signalling network is regulated by water deficit. Plant defence responses to water stress also included up-regulation of the F3H2 and LDOX genes, which are involved in anthocyanins synthesis. GFLV infection significant impacted upon the expression of genes involves in ABA biosynthesis, as NCED1 and NCED2, and upon two genes involved in the early stages of anthocyanins synthesis, as CHS2 and F3H1. We also showed that the combination of grapevine cultivar, training system, and environmental conditions impacts on gene expression
Found in: ključnih besedah
Summary of found: ...Grapevines (Vitis vinifera L.) represent one of the most...
Keywords: Vitis vinifera L., grapevine, Grapevine fanleaf virus, GFLV, grapevine disease, virus titre, distribution, fluctuation, ELISA, qPCR, ABA, drought, water status, water deficit, SWP, RHC, anthocyanins, gene expression
Published: 27.07.2015; Views: 7372; Downloads: 407
Fulltext (4,19 MB)

Abstract: Z odstranjevanjem listov v predelu grozdov se lahko spremeni mikroklima grozdov, ki lahko izzove spremembe v sekundarnem metabolizmu vinske trte, ki so odvisne tudi od časa izvedbe ukrepa. Uravnavanje sinteze aromatskih komponent je zanimivo pri belih sortah kot je sorta 'Sauvignon blanc', kjer so metoksipirazini in tioli tisti, ki oblikujejo značilno aromo vina te sorte. Eksperiment diplomske naloge smo zastavili na Oslavju (Gorica, Italija) v vinogradu sorte grozdja 'Sauvignon blanc' (Vitis vinifera L.). Želeli smo preveriti vpliva odstranjevanja listov v predelu grozdja pred in po cvetenju na količino in kakovost pridelka ter aromatske lastnosti grozdja in vina. Količinski parametri pridelka so pokazali majhne vplive izvedenih ukrepov razlistanja; pozno razlistanje na količino pridelka ni vplivalo, v nasprotju z razlistanjem pred cvetenjem, kjer smo opazili rahlo zmanjšanje pridelka po trsu in mase grozdov. Tudi pri osnovnih zrelostnih parametrih smo opazili manjše spremembe, predvsem večje vsebnosti topne suhe snovi pri razlistanju pred cvetenjem. Pri aromatskih komponentah smo zaznali vpliv razlistanja pred cvetenjem na količino prekurzorjev tiolov tako v grozdju kot tudi vinu; večjo vsebnost 4-merkapto-4-metilpentan-2-on (4MMP) in nižje koncentracije 3-merkaptoheksan-1-ol (3MH). S poznejšim odstranjevanjem listov smo zmanjšali koncentracije 4MMP, na vsebnost 3MH ta ukrep ni vplival. Tudi s senzorično oceno vina smo potrdili pomembne vplive razlistanja pred in po cvetenju na določene note v aromi vina 'Sauvignon blanc'. Leaf removal changes cluster microclimate, and thus modifications in the secondary metabolism are triggered, but differently as regard to the timing of application. In case of white grape varieties, the interest on the modification of aroma characteristics is searched, and in case of 'Sauvignon blanc', the shift in concentration of methoxypyrazines and thiols is responsible for the bouquet of the wines. An experimental trial was set up in Oslavia (Gorizia, Italy) with the aim to evaluate how pre-flowering and post-flowering leaf removal applied on 'Sauvignon blanc' vines could change the aromatic occurrence in grapes and wines. The yield parameters were slightly affected by the treatments of leaf removal; while late leaf removal did not impact on production, pre-flowering leaf removal slightly promoted a reduction on yield and cluster weight. Also basic maturation parameters were slightly changed, mainly higher soluble solids in case of pre-flowering leaf removal. As regard aromatics, both thiol precursors in grapes and thiols in wines revealed to be shifted in case of pre-flowering leaf removal, with higher values of 4-mercapto-4-methyl-pentan-2-one and lower values of 3-mercaptohexan-1-ol. In case of late leaf removal lower concentration of 4MMP were revealed and similar of 3MH. Also the degustation of the wines revealed some peculiarities of pre-flowering and late leaf removal treatments for some important sensorial notes of 'Sauvignon blanc' wines.
Found in: ključnih besedah
Keywords: Vitis vinifera L. cv. 'Sauvignon blanc', razlistanje pred cvetenjem, razlistanje po cvetenju, aromatske komponente, tioli, LC-MS Vitis vinifera L. cv. 'Sauvignon blanc', pre-flowering leaf removal, post-flowering leaf removal, aromatic compounds, thiols, LC-MS
Published: 14.01.2016; Views: 6905; Downloads: 295
Fulltext (1,30 MB)

Abstract: Poleg sorte, geo-klimatskih pogojev in vinogradniških strategij v vinogradu so tudi vinarjeve odločitve glede izbora vinifikacijskih postopkov tiste, ki lahko odločilno vplivajo na končno kakovost vina, vključno z njegovimi aromatskimi značilnostmi. Z različnimi prijemi ali postopki pred alkoholno fermentacijo in med njo lahko vplivamo predvsem na ekstrakcijo in ohranitev primarnih ter na tvorbo sekundarnih aromatskih spojin. V okviru diplomskega dela smo s pomočjo modernih analitskih pristopov metabolnega profiliranja in tehnike GC/MS/MS preučevali vpliv različnih tehnoloških postopkov predelave grozdja (krioekstrakcija s suhim ledom, stik s celimi jagodami med fermentacijo, klasični pristop-kontrola) na vsebnost prostih in vezanih aromatičnih spojin v mladih vinih Zelen, letnik 2014. Preučili smo tudi vpliv obravnavanih tehnologij na senzorične lastnosti, vezane na zaznave vonja v mladih vinih. Rezultati enoletnega poskusa so nakazali, da lahko s pomočjo krioekstrakcije v vinih Zelen povečamo izplene skupnih prostih aromatičnih kislin, estrov in terpenov, po drugi strani pa smo zaznali le trend povečanja vsebnosti skupnih višjih alkoholov pri vzorcih iz postopka dodajanja jagod med fermentacijo. V primeru vezanih aromatskih spojin smo s pomočjo postopka dodajanja jagod v primerjavi s kontrolo opazili trende povečanja vsebnosti nekaterih vezanih estrov, norizoprenoidov in višjih alkoholov, krioekstrakcija pa je večinoma povzročila trende k niţjim vsebnostim vezanih aromatskih spojin glede na kontrolne vzorce. Nazadnje so se tudi senzorična opazovanja z vonjem povezanih lastnosti vin zaključila preteţno v prid postopku z dodajanjem jagod med fermentacijo.
Found in: ključnih besedah
Keywords: 'Zelen' (Vitis Vinifera L.), alternativni pristopi v predelavi grozdja, krioekstrakcija, dodajanje sveţih jagod med alkoholno fermentacijo, proste aromatične spojine v vinu, vezane aromatične spojine v vinu, senzorika vina
Published: 23.01.2017; Views: 6432; Downloads: 302
Fulltext (1,16 MB)

Found in: ključnih besedah
Summary of found: ...Merlot (Vitis vinifera L.), wine aroma, wine sensory evaluation,...
Keywords: Merlot (Vitis vinifera L.), wine aroma, wine sensory evaluation, targeted metabolomics, carbonic maceration
Published: 18.04.2017; Views: 4169; Downloads: 0
Fulltext (846,88 KB)

Abstract: The aim of this study was to explore the diversity of fermentative yeast species in a non-vineyard and vineyard environment, and exploit their oenological potential. For this purpose we collected plant and soil material in the vineyard (located in Črniče in Vipava Valley) planted with Vitis vinifera L. and in the forest (forest in Vipava Old Castle), and by using a selective medium with high ethanol and sugar content we managed to obtain 35 isolates. By sequencing the D1/D2 domain of the 26S rDNA we identified nine different yeast species. The oenological potential of identified yeasts was further investigated by employing a series of tests, such as growth at low pH values, tolerance to ethanol and sulfur, and H2S production ability. Based on the results of these tests we selected four different yeast species for the microvinification of Vitis vinifera L. cv. ‘Pinot Noir’ grape juice. A commercial strain Saccharomyces cerevisiae Lalvin D47 was also included as a control in the fermentation experiment. Fermentation monitoring was done by measuring daily weight loss and microbiological analysis in the middle of fermentation. For the final wines, sugars were determined and sensorial evaluation performed. Among four tested yeasts, S. paradoxus IVV 32 and Torulaspora delbrueckii IVV 36 appeared to be the most promising for winemaking, but further studies should be carried out.
Found in: ključnih besedah
Summary of found: ...Črniče in Vipava Valley) planted with Vitis vinifera L. and in the forest (forest in...
Keywords: wine, Vitis vinifera L. cv. ‘Pinot Noir’, biodiversity, yeasts, fermentation
Published: 10.07.2017; Views: 4852; Downloads: 274
Fulltext (2,57 MB)