Dissertations / Theses on the topic 'Grape berry development'

Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Grape quality is important for the producer, exporter and the consumer. Consumers judge table grapes according to their size, colour, taste and shelf life. The consumer’s prerequisites will influence the producer. Therefore, it is essential to know how the table grape berry develops so that it can be manipulated, favouring the postharvest quality and shelf life. This study was performed on Prime and Crimson Seedless, both grafted onto Ramsey, in the Paarl district of South Africa. The aim of this study was to describe and quantify table grape berry development and compositional changes taking place throughout growth and ripening. The effect of sugar:acid ratio on postharvest shelf life was also evaluated. To evaluate whether berry size influenced the measured development parameters, three berry sizes were induced for both cultivars by using plant bioregulators such as gibberellic acid (GA3) and forchlorfenuron – synthetic cytokinin (CPPU) or girdling. The following sizes were obtained for Prime: (i) small berries (<20 mm) with no treatment, which acted as the control; (ii) medium berries (20-24 mm) obtained by 15 ppm GA3 application at 8 mm berry size; (iii) large berries (>24 mm) obtained by combination of 15 ppm GA3 and 1 ppm CPPU application at 8 mm berry size. Crimson Seedless berry sizes were as follows: (i) small berries (<18 mm) with no treatment, which acted as the control; (ii) medium berries (18-22 mm) treated with 10 ppm GA3 at 7 mm berry size; (iii) large berries (>22 mm) treated with 10 ppm GA3 and vines were girdled at 7 mm berry size. To evaluate the effect of sugar:acid ratio on postharvest shelf life, grapes were stored for five weeks at -0.5 ˚C and another week at 7.5˚C. The bunches were evaluated for loose berries, browning, soft tissue breakdown, decay and berry split. The following components were analysed for both cultivars to determine changes in berry composition throughout the season: berry fresh weight, total soluble solids (TSS), glucose, fructose, titratable acidity (TA), tartaric acid, malic acid, abscisic acid (ABA) and total phenols. Total and individual anthocyanins were analysed for Crimson Seedless. Differences were obtained for the three berry sizes for both cultivars. Véraison, representing the start of ripening, started at the same time in successive seasons: 21 days after pea size berry (5 mm berry diameter) for Prime and 28 days after pea size berry (5 mm berry diameter) for Crimson Seedless. A lag stage was not observed, at seven day sampling intervals, for either of the cultivars. Components such as TSS, glucose, fructose and TA content per berry were influenced by berry size in either one or in both seasons for both cultivars. Significant changes in component concentration were detected at the start of, or around véraison. Sugar concentrations (TSS) already started to increase for both cultivars before the start of véraison. At véraison, concentrations of glucose, fructose and ABA increased while concentrations of TA, tartaric acid, malic acid and total phenols decreased. Total anthocyanins in Crimson Seedless started to increase one week after véraison commenced. The main anthocyanin found in Crimson Seedless was peonidin-3-glucoside. During ripening a 1:1 glucose:fructose ratio was detected in both cultivars. Prime tartaric:malic acid ratio was lower than Crimson Seedless tartaric:malic acid ratio in both seasons. Tartaric acid was the main organic acid found in Prime, while malic acid was the main organic acid found in Crimson Seedless. No significant differences were found in the postharvest defects between the different berry sizes. However, tendencies for differences were observed which led to the assumption that medium size berries were more prone to loose berries in both cultivars. Large berries showed a higher percentage berry split for both cultivars. Crimson Seedless second harvest date took place 24 hours after rainfall which could have very likely led to the higher percentages berry defects compared to the first season. Greater berry decay was found with later harvest dates for both cultivars. No significant differences were found for the TSS:TA ratio between the three berry sizes for both cultivars. Postharvest defects were therefore found not only to be influenced by TSS:TA ratio but rather by harvest date and packing procedures. Environmental conditions prior to harvest also had an impact on postharvest shelf life.
AFRIKAANSE OPSOMMING: Druif kwaliteit is belangrik vir die produsent, uitvoerder en verbruiker. Tafeldruiwe word gekeur deur die verbruiker volgens grootte, kleur, smaak en raklewe. Die verbruiker se voorkeure sal dus die produsent beïnvloed. Daarom is dit belangrik om te weet hoe tafeldruiwe ontwikkel ten einde korrelsamestelling te manipuleer om na-oes kwaliteit en raklewe te kan bevoordeel. Hierdie studie is uitgevoer op Prime en Crimson Seedless, beide geënt op Ramsey, in die Paarl distrik van Suid Afrika. Die doel van die studie is om vas te stel hoe korrelsamestelling gedurende groei en rypwording verander. Die effek van suiker:suurverhouding op na-oes raklewe is ook geëvalueer. Om te kan meet of korrel grootte die gemete parameter beïnvloed is drie korrelgroottes verkry vir albei kultivars deur die gebruik van plant bioreguleerders, te wete gibbereliensuur (GA3) en sintetiese sitokiniene (CPPU), of ringelering. Die volgende korrelgroottes is verkry vir Prime: (i) klein korrels (<20 mm) d.m.v. geen behandeling, geklassifiseerd as kontrole; (ii) medium korrels (20-24 mm) d.m.v. ‘n 15 dpm GA3 behandeling by 8 mm korrelgrootte; (iii) groot korrels (>24 mm) d.m.v. ‘n kombinasie van 15 dpm GA3 en 1 dpm CPPU by 8 mm korrelgrootte. Crimson Seedless korrelgroottes was soos volg: (i) klein korrels (<18 mm) d.m.v. geen behandeling, wat as kontrole gedien het; (ii) medium korrels (18-22 mm) d.m.v. ‘n 10 dpm GA3 behandeling by 7 mm korrelgrootte; (iii) groot korrels (>22 mm) d.m.v. ‘n 10 dpm GA3 behandeling en gelyktydige ringelering by 7 mm korrelgrootte. Om die effek van suiker:suur verhouding op na-oes houvermoë te kon evalueer was druiwe gestoor vir vyf weke by -0.5˚C en ‘n verdere week by 7˚C. Die trosse is geëvalueer vir loskorrels, verbruining, sagte weefsel afbreek, verval en korrelbars. Die volgende komponente is geanaliseer vir albei kultivars om veranderinge in korrelsamestelling gedurende die seisoen te bepaal: vars korrelgewig, totale oplosbare vaste stowwe (suikerinhoud), glukose, fruktose, titreerbare sure, wynsteensuur, appelsuur, absisiensuur en totale fenole. Die totale en individuele antosianiene is ook vir Crimson Seedless gemeet. Beduidende verskille tussen die drie korrelgroottes vir albei kultivars is verkry. Deurslaan, naamlik die begin van rypwording, het op dieselfde dag in opeenvolgende seisoene plaasgevind: 21 dae na ertjiekorrel grootte (5 mm korrel deursnee) vir Prime en 28 dae na ertjiekorrel grootte (5 mm korrel deursnee) vir Crimson Seedless. In teenstelling met die tipiese korrel ontwikkelingspatroon is ‘n rusfase nie waargeneem by beide kultivars nie. Komponente soos suikerinhoud, glukose, fruktose en titreerbare suur inhoud per korrel is deur korrelgrootte beïnvloed in een of albei seisoene vir beide kultivars. Suiker konsentrasie van albei kultivars het reeds voor deurslaan begin toeneem. By deurslaan het die konsentrasies van glukose, fruktose en absisiensuur inhoud toegeneem, terwyl die konsentraies van titreerbare sure, wynsteensuur, appelsuur en totale fenole gedaal het. Totale antosianiene in Crimson Seedless het ‘n week na deurslaan begin toeneem. Die hoof antosianien in Crimson Seedless is peonidien-3-glukosied. Gedurende rypwording was daar ‘n 1:1 glukose:fruktose verhouding gevind vir beide kultivars. In terme van sure is Prime se wynsteensuur:appelsuur verhouding laer as in Crimson Seedless vir albei seisoene. Wynsteensuur is die hoof organiese suur in Prime terwyl appelsuur die hoof organiese suur in Crimson Seedless is. Geen betekenisvolle verskille vir na-oes houvermoë tussen korrelgroottes is waargeneem vir beide kultivars nie. Daar was egter tendense wat aanleiding gegee het in die aanname dat medium grootte korrels geneig is tot loskorrels in albei kultivars. Groot korrels het ‘n hoër korrelbars persentasie getoon vir beide kultivars. Crimson Seedless se tweede oes het plaasgevind 24 uur na reënval, wat aanleiding gegee het tot hoër persentasies korrelbederf. Hoër persentasie korrelbederf was ook gevind met later oesdatums. Geen beduidende verskille is gevind vir suiker:suur verhouding tussen die drie korrelgroottes vir beide kultivars nie. Dus word na-oes houvermoë nie net deur suiker:suur verhouding beïnvloed nie, maar ook deur oestyd en verpakkingsprodsedures. Omgewingsomstandighede voor oes kan ook na-oes houvermoë beïnvloed.

Errata tipped in behind back end paper. Bibliography: leaves 104-123. The work described in this thesis was undertaken to document the accumulation of amino acids during grape berry development and to investigate the mechanisms underlying the significant accumulation of proline late in ripening in some cultivars. (conclusion)

Prohexadione-calcium (P-ca), as ApogeeTM, was evaluated in 2000 and 2001 for impact to grape vegetative and reproductive development. In 2000, P-ca (250 mg/L) was applied to Seyval, Cabernet Sauvignon, and Cabernet franc (125, 250, and 375 mg/L). P-ca reduced primary shoot growth for all cultivars and decreased cane pruning weight of Seyval. P-ca (375 mg/L) increased Cabernet franc canopy gaps but increased Cabernet Sauvignon lateral leaf area and leaf layer number. P-ca reduced components of yield for all cultivars. In 2001, P-ca (250 mg/L) was applied singularly at weekly intervals to Cabernet Sauvignon clusters and pre and post-bloom to Cabernet franc and Chardonnay canopies. Application at E-L stages 21 and 23 decreased Cabernet Sauvignon fruit set whereas application at E-L stages 26, 27, and 29 reduced berry weight without impacting fruit set. Berry weight reduction correlated to higher color intensity (420+520 nm), anthocyanins, total phenols and phenol-free glycosyl-glucose (PFGG). Cabernet franc vegetative and reproductive development was generally not affected yet treatment increased absorbance at 280, 420, and 520 nm, color intensity, anthocyanins and total phenols. Pre-bloom applications inhibited Chardonnay vegetative development, and reduced components of yield, and fruit chemistry values: hydroxycinnamates, total phenols, flavonoids, PPFG and absorbance at 280 and 320 nm. Post-bloom applications did not affect Chardonnay vegetative or reproductive development, yet increased PFGG. Treatment did not affect Chardonnay wine chemistry but two post-bloom applications increased Cabernet franc wine anthocyanins and total phenols. Wine aroma and flavor triangle difference tests did not indicate significant treatment differences.
Master of Science

Les flavonoïdes (anthocyanes, flavonols et proanthocyanidines) sont des éléments clés de la qualité organoleptique des baies de raisin. Chez les végétaux, l’expression des gènes de la voie de biosynthèse de ces composés est contrôlée par des complexes protéiques organisés autour des facteurs de transcription de type MYB. Dans le cadre de cette thèse, une première approche s’est intéressée aux mécanismes de régulation de l’expression du gène VvMyb5a et de l’activité biologique de la protéine codée par ce gène. L’analyse du promoteur VvMyb5a a montré que son activité au cours du développement de la baie serait plutôt placée sous contrôle hormonal. Des expériences de double hybride ont révélé que la protéine VvMyb5a pouvait interagir avec une protéine kinase de type GAMYB et une protéine WD40. Une deuxième approche, basée sur l’analyse globale du transcriptome de mutants naturels de vigne affectés dans la biosynthèse des anthocyanes, a permis d’identifier deux nouveaux gènes MYB nommés VvMybPA1 et VvMyb24. L’expression différentielle de ces gènes dans des baies de cépages rouges et blancs a été confirmée et leurs caractérisations fonctionnelles ont été engagées chez Arabidopsis thaliana
Flavonoids, like anthocyanins, flavonols and condensed tannins, are key elements of he organoleptic quality of grape berries. In plants, expression of genes encoding enzymes of he flavonoid biosynthetic pathway is controlled by small protein complexes organised around MYB transcription factors. In the present work, we first focused on the regulatory mechanisms of VvMyb5a expression and on the biological activity of the corresponding protein. Promoter analysis indicated that VvMyb5a expression is probably mainly controlled by hormones. A yeast two-hybrid screen revealed that VvMyb5a can interact with a GAMYB ype protein kinase and a WD40 protein. In a second time, global transcriptome analysis of grapevine natural mutants deficient in anthocyanin biosynthesis led to the identification of wo new MYB genes, named VvMybPA1 and VvMyb24. Differential expression of these two genes in red and white berry skins was confirmed by RT-PCR and their functional characterizations have been initiated in Arabidopsis thaliana

Thesis (M.S. in horticulture)--Washington State University, May 2010.
Title from PDF title page (viewed on July 7, 2010). "Department of Horticulture and Landscape Architecture." Includes bibliographical references (p. 113-119).

Le changement climatique devrait modifier les conditions environnementales dans le futur, affectant ainsi l'agriculture. Le Tempranillo, une variété de vigne rouge (Vitis vinifera L .) largement cultivée au niveau international, pourrait être affecté par l’augmentation des températures moyennes mondiales et des niveaux de CO2 dans l’atmosphère, ainsi que par la diminution de la disponibilité en eau sur sa zone traditionnelle de culture. L'utilisation de la diversité intra-variétale a été proposée comme une stratégie pour essayer de conserver la typicité du vin et les variétés régionales dans les conditions de cultures futures, en déplaçant la phase de maturation vers des périodes aux conditions environnementales plus favorables. L’objectif de cette thèse était donc de déterminer la réponse de différents clones de Tempranillo aux conditions environnementales simulées de 2100, en se concentrant sur la croissance et le développement des plantes, ainsi que sur la composition des baies. Des boutures fructifères de clones de Tempranillo, dont la longueur du cycle de reproduction était différente, ont été exposées à différents scénarios climatiques dans des serres à gradient de température (TGG) et des serres de chambre de croissance (GCG) depuis la fructification jusqu’à la maturité. Les impacts de la température élevée (+4 ° C), du CO2 élevé (700 ppm) et du déficit en eau, combinés ou non, ont été évalués. Les résultats montrent une augmentation de la croissance végétative et une réduction de la production dues aux températures élevées. La concentration élevée de CO2 a également augmenté la croissance végétative et l'activité photosynthétique. Néanmoins, un processus d'acclimatation a été observé, celui-ci étant plus fort lorsqu’un haut niveau de CO2 est combiné à une température élevée. Le déficit en eau a fortement réduit l'activité photosynthétique et la croissance végétative, occultant les effets de la température et du CO2. La température élevée, que ce soit individuellement ou associée à des niveaux élevés de CO2, a accéléré l'accumulation de sucres et la date de maturité a été avancée, mais ces effets ont été atténués par le déficit en eau. La dégradation de l’acide malique a également été favorisée par l’augmentation de la température, en particulier lorsque cette dernière est associée à une concentration élevée de CO2 et à un déficit en eau. La concentration et le profil des acides aminés ont été influencés par les températures élevées, un niveau de CO2 élevé et, en particulier, par un déficit en eau. L'augmentation de CO2 a réduit l'effet de la température sur le découplage de l’accumulation des anthocyanes par rapport à celle des sucres ; cependant, la combinaison d’une température élevée, d’un haut niveau de CO2 et d’un déficit en eau a conduit à un déséquilibre entre ces deux composés du raisin. Le profil des anthocyanes a été modifié par le changement climatique, une température élevée augmentant la proportion des formes acylées tandis qu’un haut niveau de CO2 et un déficit hydrique ont favorisé quant à eux l'abondance relative de la malvidine, et des formes acylées, méthylées et trihydroxylées. Les clones étudiés ont montré des différences dans leur développement phénologique, leur croissance végétative et reproductive, ainsi que dans la composition de leurs raisins. En outre, les résultats révèlent l’existence d’une réponse différentielle des clones de Tempranillo aux conditions environnementales prévues pour 2100 en termes de performance de la plante et de composition du raisin. De façon générale, parmi les clones étudiés, RJ43 fut le plus affecté par les conditions de croissance futures (températures élevées, haut niveau de CO2 et déficit en eau) aussi bien en termes de développement phénologique qu’en termes de concentration en anthocyanes et de leur profil.[...]
Climate change is expected to modify future environmental conditions, therefore affecting agriculture. Tempranillo, a largely cultivated worldwide grapevine (Vitis vinifera L.) red variety, will be affected by the increase of global mean temperature and atmospheric CO2 levels and the decrease of water availability in its cultivation area. The use of the intra-varietal diversity has been proposed as a strategy for keeping wine typicity and regional varieties cultivation under future growing conditions by shifting the ripening phase to more favourable environmental conditions. The aim of the thesis was to determine the response of different clones of Tempranillo to simulated 2100 environmental conditions, focusing on plant growth and development, as well as on berry composition. Fruit-bearing cuttings of Tempranillo clones, which differed in the length of their reproductive cycle, were exposed from fruit set to maturity to different scenarios of climate change in temperature gradient greenhouses (TGG) and growth chamber greenhouses (GCG). The impact of elevated temperature (+4 °C), elevated CO2 (700 ppm) and water deficit, both in combination or independently, were evaluated. The results show an increment of vegetative growth and a reduction of yield due to high temperatures. Elevated CO2 concentration also increased vegetative growth and photosynthetic activity, even though an acclimation process was observed, being stronger when combined with high temperature. Water deficit reduced severely the photosynthetic activity and vegetative growth, overshadowing the temperature and CO2 effects. Elevated temperature, both individually and combined with high CO2 levels, hastened sugar accumulation and advanced maturity, but these effects were mitigated by water deficit. Malic acid degradation was also enhanced by high temperature, especially when combined with elevated CO2 and water deficit. Amino acid concentration and profile were affected by high temperature, elevated atmospheric CO2 and, especially, water deficit. Elevated CO2 reduced the effect of temperature decoupling the anthocyanin and TSS accumulation; however, the combination of elevated temperature, high CO2 and water deficit led to the imbalance between these two grape components. Anthocyanin profile was modified by climate change, high temperature increasing the relative abundance of acylated forms and both elevated CO2 and drought favouring the relative content of malvidin and acylated, methylated and tri-hydroxylated forms. The clones studied showed differences in their phenological development, vegetative and reproductive growth, as well as in their grape composition. In addition, the results reveal the existence of a differential response of Tempranillo clones to the environmental conditions projected for 2100 in relation to plant performance and grape composition. In general, RJ43 was the most affected by the future growing conditions (high temperature, elevated CO2 and water deficit) among the clones studied in terms of phenology and anthocyanin concentration and profile. Conversely, VN31 maintained the highest anthocyanin and anthoycianin:TSS ratio, whereas 1084 had the lowest sugar, malic acid and anthocyanin levels. The differences observed in the response of the clones to climate change not always depended on their reproductive cycle length

Copies of author's previously published articles inserted. Bibliography: leaves 143-167. Temperature may affect fruit-set in grapevines through its effect on the development of the flowers up to flower opening and on pollination, be it on the germination of the pollen and the growth of the pollen tube, or on the post-fertilisation growth of the ovule.

Au cours des prochaines années, il est prédit que le changement climatique va influencer la production des cultures et impacter négativement le secteur agricole. Parmi les cultures mondiales majeures, la vigne est cultivée pour ses baies, qui sont la base de produits à forte valeur ajoutée (vin, liqueurs, et métabolites secondaires utilisés dans les industries pharmaceutiques et cosmétologiques) et dont le métabolisme est fortement sensible au climat. Cependant, la réponse au niveau de la composition de la baie ainsi que les mécanismes moléculaires sous-jacents mettant en évidence la capacité de l’interaction porte-greffe/greffon à influencer le métabolisme de la baie dans des conditions de stress hydrique est encore très peu étudiée et compris. Dans ce contexte, cette thèse a eu pour objectifs de répondre à ces questionnements en combinant des approches ecophysiologique, biochimique et transcriptomique. Vitis vinifera cv. Pinot noir greffé soit sur le porte greffe 110R (tolérance à la sécheresse, vigueur conférée moyenne à forte) ou 125AA (sensible à la sécheresse, forte vigueur conférée) ont été étudié au cours de 3 années (2009, 2010 et 2011), au vignoble et dans des conditions témoin (pluviométrie normale) ou de stress hydrique provoqué. Différents paramètres physiologiques (statut hydrique et rendement) ainsi que le profil métabolique de la baie (sucres, acides organiques, acides aminés et anthocyanes) ont été caractérisés à quatre stades de développement (E-L 33, E-L 35, E-L 36, E-L 38). D’autre part, une analyse microarray sur génome complet a également été réalisée pour deux années (2009 et 2010) et deux stades de développement critiques et représentatifs (E-L 35 et E-L 36). Dans son ensemble, cette thèse fournit des nouveaux éléments concernant la réponse métabolique de la baie au porte-greffe et à la contrainte hydrique, et met en évidence des possibles mécanismes moléculaires impliqués dans cette réponse
Climate change is expected to influence crop production and to impact negatively the agricultural sector in the future. Among the major crops cultivated worldwide, grapevine provides berries that are the basis of high added value products (wines, liquors, and secondary metabolites used in the pharmaceutical and cosmetological industry) and whose metabolism is strongly sensitive to climate (vintage effect). However, the response of berry composition and the molecular mechanisms underlying the ability of rootstock/scion interaction to influence grape berry metabolism under drought stress are still poorly understood. In this context, this work aimed to fill the gaps on the aforementioned questions by combining comprehensive ecophysiological measurements, detailed metabolite analysis, and whole-genome transcriptome analysis. Vitis vinifera cv. Pinot noir grafted on either rootstock 110R (drought tolerant, mid- to high vigor) or 125AA (drought sensitive, high vigor) were studied during three growing seasons (2009, 2010, and 2011) in the field under normal rainfall or water shortage conditions. We characterized different physiological parameters (water status and yield components) and berry metabolomic profiles (sugars, organic acids, free amino acids and anthocyanins) during four developmental stages (E-L 33, E-L 35, E-L 36, E-L 38). Besides we also performed a microarray analysis in two years (2009 and 2010) at two critical and representative developmental stages (E-L 35 and E-L 36). Overall, this work provides novel insights into the response of grape berry metabolites to rootstock and to drought and uncovers some possible molecular mechanisms underlying the berry response to different rootstock/water status combinations

Hormones control plant development by coordinating changes in the expression of numerous genes at crucial times in a tissue and organ-specific manner. They have been implicated in controlling various aspects of grape berry development, in particular, the important process of ripening and are used in some crops to control growth and ripening. Abscisic acid (ABA), is associated in grapevine with the response to water stress but may also have a role in berry ripening. We have shown over three seasons that ABA levels in Cabernet Sauvignon berries increase dramatically at veraison, consistent with it being involved either as a trigger for ripening or as a response to the increase in sugars that occurs at this time. Net ABA accumulation doesn't occur until veraison, the decrease in ABA concentration in the first phase of berry development being due to berry expansion. The decrease in ABA that occurs later in development is likely to be due to a combination of catabolism and sequestration into the bound form. The genes crucial to ABA synthesis, 9-cis-epoxycarotenoid dioxygenase (NCED) and zeaxanthin epoxidase (ZEP), were expressed throughout berry development and no clear correlation was found between their levels and that of ABA. Laboratory studies have shown that isolated berries respond to the presence of sucrose through an increase in ABA biosynthesis pathway gene expression (NCED and ZEP). This resulted in de novo synthesis of ABA as inhibition of the carotenoid synthesis pathway by a phytoene desaturase inhibitor prevented ABA accumulation. Replicated field trials clearly showed that ABA treatments can be effective in significantly enhancing ripening when applied in at or near the end of the first period of berry expansion. Colour accumulation in the skins commenced earlier in ABA-treated fruit as did the increase in sugar levels. ABA treatment also advanced the timing of the second phase of berry expansion as it appeared to eliminate the lag phase of berry growth. Taken together these data demonstrate that ABA is likely to play some part in the control of berry ripening and can be used to advance the timing of ripening. Further investigation into the characteristics of ABA-treated fruit will be needed to investigate the compositional character of treated fruit and to gauge its suitability for winemaking. An ability to control the timing of ripening may provide considerable benefits to the wine industry in terms of wine style/quality and for winery scheduling.
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1278807
Thesis (Ph.D.) - The University of Adelaide, School of Agriculture, Food & Wine, 2007.

Hormones control plant development by coordinating changes in the expression of numerous genes at crucial times in a tissue and organ-specific manner. They have been implicated in controlling various aspects of grape berry development, in particular, the important process of ripening and are used in some crops to control growth and ripening. Abscisic acid (ABA), is associated in grapevine with the response to water stress but may also have a role in berry ripening. We have shown over three seasons that ABA levels in Cabernet Sauvignon berries increase dramatically at veraison, consistent with it being involved either as a trigger for ripening or as a response to the increase in sugars that occurs at this time. Net ABA accumulation doesn't occur until veraison, the decrease in ABA concentration in the first phase of berry development being due to berry expansion. The decrease in ABA that occurs later in development is likely to be due to a combination of catabolism and sequestration into the bound form. The genes crucial to ABA synthesis, 9-cis-epoxycarotenoid dioxygenase (NCED) and zeaxanthin epoxidase (ZEP), were expressed throughout berry development and no clear correlation was found between their levels and that of ABA. Laboratory studies have shown that isolated berries respond to the presence of sucrose through an increase in ABA biosynthesis pathway gene expression (NCED and ZEP). This resulted in de novo synthesis of ABA as inhibition of the carotenoid synthesis pathway by a phytoene desaturase inhibitor prevented ABA accumulation. Replicated field trials clearly showed that ABA treatments can be effective in significantly enhancing ripening when applied in at or near the end of the first period of berry expansion. Colour accumulation in the skins commenced earlier in ABA-treated fruit as did the increase in sugar levels. ABA treatment also advanced the timing of the second phase of berry expansion as it appeared to eliminate the lag phase of berry growth. Taken together these data demonstrate that ABA is likely to play some part in the control of berry ripening and can be used to advance the timing of ripening. Further investigation into the characteristics of ABA-treated fruit will be needed to investigate the compositional character of treated fruit and to gauge its suitability for winemaking. An ability to control the timing of ripening may provide considerable benefits to the wine industry in terms of wine style/quality and for winery scheduling.
Thesis (Ph.D.) - The University of Adelaide, School of Agriculture, Food & Wine, 2007.

Ascorbate (Asc, Vitamin C) is a ubiquitous and abundant antioxidant in plants. The biological role of Asc is composed of the following three functions: as an antioxidant (radical scavenger), an enzyme cofactor and a donor/acceptor in electron transport across membranes. This present research was focussed on the additional, less comprehensively investigated function of Asc as a precursor of tartaric acid (TA) and oxalic acid (OA) in certain species. Although the in planta function of TA is unclear, it is well known as the dominant organic acid in grape (Vitis vinifera) berries. TA is therefore largely responsible for the low berry pH, whereas in other fruits, the majority of the acidity is conferred by malic, citric and ascorbic acids. Earlier research investigating the Asc-derived TA biosynthetic pathway revealed several intermediates and one characterised enzyme. Research investigating metabolism of the Asc precursor in TA and OA accumulating plant species is now required. The aim of this present research was to therefore investigate the factors which may regulate the accumulation of Asc and those which in turn regulate the fate of Asc in fruit. Sensitive methods were developed for the extraction and analysis of Asc, TA and OA from vegetative and fruit tissues. These methods were used to demonstrate that Asc and its catabolites are widely distributed throughout the grapevine; however, the total Asc pool and the Asc to dehydroascorbic acid (DHA) ratio were shown to be significantly greater in leaves than berries at all physiological stages of maturity. This research further demonstrated that immature grape berries rapidly accumulate Asc in situ from D-mannose and L galactose (precursors of the Smirnoff-Wheeler Asc biosynthetic pathway). Developmental regulation of Asc biosynthetic, recycling (redox) and catabolic genes were demonstrated in grape berries. The gene transcription results of this study strongly suggested that Asc biosynthesis in immature berries is supported by the Smirnoff-Wheeler biosynthetic pathway whilst the alternative 'carbon-salvage' pathway of Asc biosynthesis supports post-veraison accumulation of Asc. A positive correlation between the developmental accumulation of Asc and TA was observed and the capacity for in situ Asc catabolism in immature berries, generating both TA and OA products, was directly demonstrated. The accumulation of Asc and TA was shown to be influenced by sunlight intensity and, putative light-responsive Asc biosynthetic and recycling genes were identified. The results also demonstrated that OA accumulates in berries independent of sunlight intensity. The outcomes of this research strongly suggested that TA biosynthesis is regulated by the availability of its precursor Asc; however, it is unlikely that the biosynthesis of OA is dependent on the availability of Asc. In conclusion, the results of this present study highlighted that both developmental and environmental factors influence transcription of Asc metabolic genes and the accumulation of Asc. Furthermore, these factors also influence the fate of Asc in grape berries. The low levels of accumulated Asc detected in the fruit at all stages of maturity are therefore likely to be the result of catabolism rather than a low biosynthetic capacity. The implications of Asc catabolism and the accumulation of TA and OA products on fruit growth and development are discussed.
Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2010

The grape is a non-climacteric fruit which maturation apparently does not require ethylene. Here, it is confirmed that the accumulation of anthocyanins is linked to the accumulation of a glucoslyltransferase (UFGT), whose promoter was cloned. We found 7 cis-elements ethylene-dependent. This study showed the stimulation of ufgt expression by ethylene is not dependent to MybA, transcription regulators of the ufgt. Experiments were designed to investigate all genes affected by ethylene in early ripening grapes. Among them some are in relation to variations in berry diameter. These genes are involved in the movement of water : several aquaporins, and the structure of the cell wall : polygalactoronases, xyloglucan endotransglucosylases, méthylesterase pectin, cellulose synthase and expansines. Ethylene stimulates the accumulation of most of their transcripts between 1 hour and 24 hours of incubation.

Errata tipped in behind back end paper.
Bibliography: leaves 104-123.
viii, 123 leaves : ill. ; 30 cm.
The work described in this thesis was undertaken to document the accumulation of amino acids during grape berry development and to investigate the mechanisms underlying the significant accumulation of proline late in ripening in some cultivars. (conclusion)
Thesis (Ph.D.) -- University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 2000

Lo sviluppo della bacca di vite può essere descritto come una successione di cambiamenti fisiologici e biochimici che riflettono la modulazione trascrizionale di molti geni. Nello scorso decennio molti studi trascrittomici sono stati eseguiti per descrivere in modo più approfondito questo processo di sviluppo dinamico e complesso. Tuttavia, la maggior parte di questi studi trascrittomici si sono focalizzati solo su un’unica varietà per volta e quindi vi è ancora una mancanza di risorse per poter effettuare comparazioni sullo sviluppo della bacca in differenti varietà di vite. Questa tesi riguarda la prima comparazione del trascrittoma della bacca di vite effettuato attraverso RNA sequencing di 120 campioni di RNA, corrispondenti alle bacche di dieci varietà raccolte a quattro stadi fenologici, due precedenti e due successivi all’invaiatura, in triplicato biologico. Quest’analisi RNA-seq ha mostrato un’evidente e profonda transizione del trascrittoma dalla fase verde alla maturazione che avviene all’invaiatura indipendentemente da colore della buccia e varietà, che coinvolge la soppressione di diversi processi metabolici relativi alla crescita vegetativa, e l’induzione di solo poche vie, come processi di metabolismo secondario e di risposta a stimoli biotici. Questo importante riprogramma del trascrittoma durante la maturazione è stato evidenziato da diversi approcci: correlazione con distanza di Pearson, analisi a componenti principali (PCA), O2PLS-DA, ricerca di biomarcatori, analisi clustering e network di correlazione. La creazione della prima via trascrittomica di sviluppo della bacca di vite, corrispondente a geni aventi un profilo di espressione simile durante tutto lo sviluppo indipendentemente dalla varietà, ha permesso di identificare geni coinvolti nei maggiori processi biologici che avvengono durante la maturazione del frutto. Infine, l’espressione dei geni appartenenti alla via biosintetica dei fenilpropanoidi/flavonoidi si sono mostrati insufficienti da soli nello spiegare le differenze trascrittomiche tra varietà rosse e bianche; tuttavia si presuppone che questi – probabilmente per effetto dell’accumulo di antociani nella buccia della bacca dall’inizio della maturazione – influenzino comunque il programma della fase di maturazione, determinando il coinvolgimento e reclutamento di geni appartenenti ad altri processi biologici.
Grape berry development can be described as a succession of physiological and biochemical changes reflecting the transcriptional modulation of many genes. In the last decade, many transcriptomic studies have been carried out to deeper describe this dynamic and complex development. Nonetheless, most of those transcriptomic studies focused on one single variety at a time and then there is still a lack of resources for comparing berry development in different grape varieties. This thesis describes the first berry transcriptome comparison carried out by RNA sequencing of 120 RNA samples, corresponding to 10-variety berries collected at four phenological growth stages, two pre- and two post-véraison, in biological triplication. This RNA-Seq analysis showed an evident deep green-to-maturation transcriptome shift occurring at véraison independently on skin colour and variety, which involves the suppression of diverse metabolic processes related to vegetative growth, and the induction of only a few pathways, such as secondary metabolic processes and responses to biotic stimuli. This fundamental transcriptome reprogramming during ripening was highlighted by distinct approaches: Pearson’s correlation distance, PCA, O2PLS-DA, biomarker discovery, clustering analysis and correlation network method. The establishment of the first grape berry development transcriptomic route, corresponding to the genes having similar patterns of expression during whole development independently on the variety, allowed identifying genes involved in the main biological processes occurring during berry development. Finally, the expression of phenylpropanoid/flavonoid biosynthetic pathway-related genes was found to be insufficient by itself to explain the differences between red- and white-grape transcriptomes, however it was supposed to influence – supposedly by the effect of anthocyanins accumulation in berry skin since the onset of ripening – maturation-phase transcriptional program, determining the recruitment of genes belonging to other biological processes.

The grape flavonoids include anthocyanins, tannins and flavonols, all of which contribute to grape and wine quality by influencing the colour and mouthfeel of red wine. These compounds are synthesized in different parts of the berry and during different stages of berry development. In addition, environmental and viticultural factors such as light exposure can also alter the flavonoid composition of grapes. An understanding of how synthesis of these compounds is coordinated, their relationship to wine quality and the influence of bunch light exposure on the flavonoid composition of grapes, could be used to improve fruit quality by enhanced viticultural management. The first part of this study sought to investigate the relationship between the different products of the flavonoid biosynthetic pathway (anthocyanins, flavonols and tannins), from two climatic regions (warm and cool) and determine their role in grape and wine quality. In collaboration with a major winery, whole Shiraz grapes were sampled at the weighbridge from a range of different vineyards from two climatic regions; warm (Riverland) and cool (McLaren Vale) in 2003 and 2004. A total of 80 grape samples were collected in each season and processed (i.e. 100 berries, separated into skin, seeds and juice, weighed and frozen). Anthocyanins and flavonols were measured, in triplicate, in skins by HPLC. Tannins were determined in the skins and seeds by two methods; phloroglucinol hydrolysis (HPLC) and protein precipitation (UV-VIS spectrophotometer). A comprehensive comparison of the two methods is discussed. In both years, the grapes from warm and cool climates formed two distinct data sets based on flavonoid composition. There was a correlation between anthocyanins and flavonols for both the warm and cool climate samples in both years, however those from the warm region had lower anthocyanin for a given level of flavonol. As expected, the level of tannin in the seeds was greater than in skin for all samples. In both years, there was a weak correlation between anthocyanin levels in the skin and skin tannins, but no relationship with seed tannins. These results suggest there is some co-ordination in the synthesis of anthocyanins, flavonols and skin tannins. Also, the two regions clearly separated based on yield and despite the weak correlations in both regions, the levels of total anthocyanins were inversely related to yield. In addition, there was no relationship with any of the flavonoids and grape quality, indicating the need for improvement in streaming fruit for quality using these flavonoid compounds. The second part of the study was to investigate the effect of bunch light exposure on flavonol synthesis and accumulation in Shiraz and Chardonnay grapes during development. Light-excluding boxes were applied to bunches at budburst. Boxes were removed at four sampling times; flowering, pre-veraison, veraison and harvest. At each sampling time, berry skins were sampled when the boxes were removed and then every second day (light induced), along with exposed controls for one week. Flavonol accumulation and flavonol synthase (VvFLS1) gene expression was determined by HPLC and Real Time-PCR (RT-PCR) respectively. As expected, for all four sampling times, flavonol accumulation and VvFLS1 expression in the boxed fruit was significantly less than bunches exposed to light. On removal of boxes at flowering, pre-veraison and veraison, flavonols accumulated to levels similar to that of the exposed control fruit over a period of 4-6 days. There was a significant increase in VvFLS1 expression 2 days after exposure to light in parallel with the accumulation of flavonols. At harvest, in Chardonnay, VvFLS1 expression peaked by day 4, while in Shiraz VvFLS1 expression increased linearly and was highest at day 6. In contrast to the results for the earlier sampling times, the total amount of flavonols accumulated at harvest was less than 50% of exposed controls in Chardonnay and Shiraz grapes. These results show that flavonols are able to be induced by bunch light exposure at different times during berry development, including times when flavonols are not normally being synthesised. This suggests bunch light exposure can override the developmental control of flavonol accumulation. To further investigate the light induced expression of VvFLS1 in grapevines the molecular mechanism of transcriptional control was explored. Using genomic walking PCR techniques, two Shiraz VvFLS1 promoter sequences were cloned and their sequences were analysed. These promoter sequences were ~800bp in length and were 99% identical. A putative MYB responsive element (MRE) and several light responsive elements (LRE) were identified in the promoter region of these genes. To functionally test the VvFLS1 promoter(s), a transient assay was developed in Chardonnay suspension cells. Cells were bombarded with constructs containing potential transcription factors and the VvFLS1 promoter(s), fused to a luciferase reporter vector. After 48hrs incubation in the dark, cells were harvested and luciferase activity measured as an indicator of VvFLS1 promoter activity. Of the different transcription factors tested with the VvFLS1 promoter(s) the highest luciferase activity was observed using AtMYB12 (a flavonol-specific regulator of AtFLS1 in Arabidopsis (Mehrtens et al. 2005). While this result shows activation of the VvFLS1 promoters by AtMYB12 and the development of a transient reporter assay for testing the VvFLS1 promoter(s) a grapevine transcription factor specific for VvFLS1 was sought. Two techniques were employed to identify potential transcription factor regulators of the VvFLS1 promoter(s). The first involved BLAST sequence search analysis in a grapevine expression (EST) database with AtMYB12 and the second involved using DNA microarray technology to identify candidate transcription factors that were up-regulated in light exposed Chardonnay cell suspension cultures. Thirteen potential transcription factors were identified and after correlative RT-PCR analysis (with VvFLS1 expression patterns) two candidates were selected for further isolation and characterisation. These results have made significant progress in unravelling the molecular mechanisms of regulation of the flavonol biosynthetic, however additional experiments are required to unravel the transcriptional control of flavonol biosynthesis. This investigation contributes to our knowledge of flavonoid synthesis in grapes; how it is coordinated, the relationship with wine quality, and the influence of light particularly on synthesis of flavonols. It also explores the molecular mechanisms of VvFLS1 control, through isolation of the VvFLS1 promoter and identification of potential transcription factors, which may regulate it. An understanding of the synthesis of flavonoids and how they may be coordinated, particularly in response to light, could be used to improve fruit quality by enhanced viticultural management.
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Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2008