Seeing the Forest through the (Phylogenetic) Trees: Functional Characterisation of Grapevine Terpene Synthase () Paralogues and Orthologues.

Gene families involved in specialised metabolism play a key role in a myriad of ecophysiological and biochemical functions. The sesquiterpene synthases represent the largest subfamily of grapevine terpene synthase () genes and are important volatile metabolites for wine flavour and aroma, as well as ecophysiological interactions. The functional characterisation of genes is complicated by a reliance on a single reference genome that greatly underrepresents this large gene family, exacerbated by extensive duplications and paralogy.

Comparative (Within Species) Genomics of the L. Terpene Synthase Family to Explore the Impact of Genotypic Variation Using Phased Diploid Genomes.

The L. terpene synthase () family was comprehensively annotated on the phased diploid genomes of three closely related cultivars: Cabernet Sauvignon, Carménère and Chardonnay. gene regions were grouped to chromosomes, with the haplotig assemblies used to identify allelic variants.

Linking Terpene Synthases to Sesquiterpene Metabolism in Grapevine Flowers.

Grapevine ( L.) terpene synthases (VviTPS) are responsible for the biosynthesis of terpenic volatiles. Volatile profiling of nine commercial wine cultivars showed unique cultivar-specific variation in volatile terpenes emitted from grapevine flowers.

Cell division and turgor mediate enhanced plant growth in Arabidopsis plants treated with the bacterial signalling molecule lumichrome.

Transcriptomic analysis indicates that the bacterial signalling molecule lumichrome enhances plant growth through a combination of enhanced cell division and cell enlargement, and possibly enhances photosynthesis. Lumichrome (7,8 dimethylalloxazine), a novel multitrophic signal molecule produced by Sinorhizobium meliloti bacteria, has previously been shown to elicit growth promotion in different plant species (Phillips et al. in Proc Natl Acad Sci USA 96:12275-12280, https://doi.

The Transcriptional Responses and Metabolic Consequences of Acclimation to Elevated Light Exposure in Grapevine Berries.

An increasing number of field studies that focus on grapevine berry development and ripening implement systems biology approaches; the results are highlighting not only the intricacies of the developmental programming/reprogramming that occurs, but also the complexity of how profoundly the microclimate influences the metabolism of the berry throughout the different stages of development. In a previous study we confirmed that a leaf removal treatment to Sauvignon Blanc grapes, grown in a highly characterized vineyard, primarily affected the level of light exposure to the berries throughout their development. A full transcriptomic analysis of berries from this model vineyard details the underlying molecular responses of the berries in reaction to the exposure and show how the berries acclimated to the imposing light stress.

Field-Grown Grapevine Berries Use Carotenoids and the Associated Xanthophyll Cycles to Acclimate to UV Exposure Differentially in High and Low Light (Shade) Conditions.

Light quantity and quality modulate grapevine development and influence berry metabolic processes. Here we studied light as an information signal for developing and ripening grape berries. A Vitis vinifera Sauvignon Blanc field experiment was used to identify the impacts of UVB on core metabolic processes in the berries under both high light (HL) and low light (LL) microclimates.

The NPC2 protein: A novel dog allergen.

Background: Dogs are an important source of indoor allergens that cause rhinoconjunctivitis, urticaria, and asthma in sensitized individuals. Can f 1 is reported as a major dog allergen, but other allergens have also been identified. Identification of immunologically important allergens is important for both the diagnosis and treatment of dog allergy.

Grapevine Plasticity in Response to an Altered Microclimate: Sauvignon Blanc Modulates Specific Metabolites in Response to Increased Berry Exposure.

In this study, the metabolic and physiological impacts of an altered microclimate on quality-associated primary and secondary metabolites in grape (Vitis vinifera) 'Sauvignon Blanc' berries was determined in a high-altitude vineyard. The leaf and lateral shoot removal in the bunch zones altered the microclimate by increasing the exposure of the berries. The physical parameters (berry diameter and weight), primary metabolites (sugars and organic acids), as well as bunch temperature and leaf water potential were predominantly not affected by the treatment.

Functional characterisation of three members of the Vitis vinifera L. carotenoid cleavage dioxygenase gene family.

Background: In plants, carotenoids serve as the precursors to C13-norisoprenoids, a group of apocarotenoid compounds with diverse biological functions. Enzymatic cleavage of carotenoids catalysed by members of the carotenoid cleavage dioxygenase (CCD) family has been shown to produce a number of industrially important volatile flavour and aroma apocarotenoids including β-ionone, geranylacetone, pseudoionone, α-ionone and 3-hydroxy-β-ionone in a range of plant species. Apocarotenoids contribute to the floral and fruity attributes of many wine cultivars and are thereby, at least partly, responsible for the "varietal character".

The genes and enzymes of the carotenoid metabolic pathway in Vitis vinifera L.

Background: Carotenoids are a heterogeneous group of plant isoprenoids primarily involved in photosynthesis. In plants the cleavage of carotenoids leads to the formation of the phytohormones abscisic acid and strigolactone, and C13-norisoprenoids involved in the characteristic flavour and aroma compounds in flowers and fruits and are of specific importance in the varietal character of grapes and wine. This work extends the previous reports of carotenoid gene expression and photosynthetic pigment analysis by providing an up-to-date pathway analysis and an important framework for the analysis of carotenoid metabolic pathways in grapevine.

Optimisation of an HPLC method for the simultaneous quantification of the major sugars and organic acids in grapevine berries.

A high performance liquid chromatographic method was developed to profile major sugars and organic acids in grapevine berries. Sugars and organic acids in grapevine berries were extracted by chloroform/polyvinylpolypyrrolidone purification. The extracts were chromatographed on an Aminex HPX-87H ion-exchange HPLC column with 5mM sulphuric acid as mobile phase.

Epigenetic regulation of PGU1 transcription in Saccharomyces cerevisiae.

The PGU1 gene of Saccharomyces cerevisiae has been shown to encode a polygalacturonase. The polygalacturonase activity in S. cerevisiae is strain specific.

Regulation of endo-polygalacturonase activity in Saccharomyces cerevisiae.

Pectolytic activity in Saccharomyces cerevisiae is due to the secretion of an endo-polygalacturonase encoded by the PGU1 gene. The ability to degrade polygalacturonic acid has been shown to vary between different strains. In this study, we attempted to elucidate how pectolytic activity is regulated in S.

Wine biotechnology in South Africa: towards a systems approach to wine science.

The wine industry in South Africa is over three centuries old and over the last decade has reemerged as a significant competitor in world wine markets. The Institute for Wine Biotechnology (IWBT) was established in partnership with the Department of Viticulture and Oenology at Stellenbosch University to foster basic fundamental research in the wine sciences leading to applications in the broader wine and grapevine industries. This review focuses on the different research programmes of the Institute (grapevine, yeast and bacteria biotechnology programmes, and chemical-analytical research), commercialisation activities (SunBio) and new initiatives to integrate the various research disciplines.