http://hdl.handle.net/2440/16 2013-05-19T13:43:37Z 2013-05-19T13:43:37Z Bizaj, Etjen Cordente, Antonio G. Bellon, Jennifer Rose Raspor, Peter Curtin, Christopher D. Pretorius, Isak Stephanus http://hdl.handle.net/2440/77737 2013-05-15T01:30:22Z 2011-12-31T13:30:00Z

Title: A breeding strategy to harness flavour diversity of Saccharomyces interspecific hybrids and minimize hydrogen sulphide production Author: Bizaj, Etjen; Cordente, Antonio G.; Bellon, Jennifer Rose; Raspor, Peter; Curtin, Christopher D.; Pretorius, Isak Stephanus Abstract: Industrial food-grade yeast strains are selected for traits that enhance their application in quality production processes. Wine yeasts are required to survive in the harsh environment of fermenting grape must, while at the same time contributing to wine quality by producing desirable aromas and flavors. For this reason, there are hundreds of wine yeasts available, exhibiting characteristics that make them suitable for different fermentation conditions and winemaking practices. As wine styles evolve and technical winemaking requirements change, however, it becomes necessary to improve existing strains. This becomes a laborious and costly process when the targets for improvement involve flavor compound production. Here, we demonstrate a new approach harnessing preexisting industrial yeast strains that carry desirable flavor phenotypes - low hydrogen sulfide (H(2) S) production and high ester production. A low-H(2) S Saccharomyces cerevisiae strain previously generated by chemical mutagenesis was hybridized independently with two ester-producing natural interspecies hybrids of S. cerevisiae and Saccharomyces kudriavzevii. Deficiencies in sporulation frequency and spore viability were overcome through use of complementary selectable traits, allowing successful isolation of several novel hybrids exhibiting both desired traits in a single round of selection.

2011-12-31T13:30:00Z Borneman, Anthony Richard Desany, Brian Riches, David Affourtit, Jason P. Forgan, Angus Henderson Pretorius, Isak Stephanus Egholm, Michael Chambers, Paul J. http://hdl.handle.net/2440/77681 2013-05-13T07:30:28Z 2011-12-31T13:30:00Z

Title: The genome sequence of the wine yeast VIN7 reveals an allotriploid hybrid genome with Saccharomyces cerevisiae and Saccharomyces kudriavzevii origins Author: Borneman, Anthony Richard; Desany, Brian; Riches, David; Affourtit, Jason P.; Forgan, Angus Henderson; Pretorius, Isak Stephanus; Egholm, Michael; Chambers, Paul J. Abstract: The vast majority of wine fermentations are performed principally by Saccharomyces cerevisiae. However, there are a growing number of instances in which other species of Saccharomyces play a predominant role. Interestingly, the presence of these other yeast species generally occurs via the formation of interspecific hybrids that contain genomic contributions from both S. cerevisiae and non-S. cerevisiae species. However, despite the large number of wine strains that are characterized at the genomic level, there remains limited information regarding the detailed genomic structure of hybrids used in winemaking. To address this, we describe the genome sequence of the thiol-releasing commercial wine yeast hybrid VIN7. VIN7 is shown to be an almost complete allotriploid interspecific hybrid that is comprised of a heterozygous diploid complement of S. cerevisiae chromosomes and a haploid Saccharomyces kudriavzevii genomic contribution. Both parental strains appear to be of European origin, with the S. cerevisiae parent being closely related to, but distinct from, the commercial wine yeasts QA23 and EC1118. In addition, several instances of chromosomal rearrangement between S. cerevisiae and S. kudriavzevii sequences were observed that may mark the early stages of hybrid genome consolidation.

2011-12-31T13:30:00Z King, Ellena Sophia Anne Johnson, Trent Edward Bastian, Susan E. P. Osidacz, Patricia Francis, Ian Leigh http://hdl.handle.net/2440/77680 2013-05-13T07:30:24Z 2011-12-31T13:30:00Z

Title: (AR)Consumer liking of white wines: segmentation using self-reported wine liking and wine knowledge Author: King, Ellena Sophia Anne; Johnson, Trent Edward; Bastian, Susan E. P.; Osidacz, Patricia; Francis, Ian Leigh Abstract: PURPOSE: The purpose of this paper is to determine the degree to which wine consumers in South Australia have different liking for white wine styles, and to relate reported liking to wine knowledge and demographic differences. DESIGN/METHODOLOGY/APROACH: group of 150 regular white wine drinking consumers from the Adelaide metropolitan area responded to a wine habits and attitudes questionnaire. Consumers were segmented based on self-reported liking of white wine styles, with three distinct segments identified. FINDINGS: Sauvignon Blanc wine likers were mainly younger females with low wine knowledge who reported not drinking Chardonnay wines. Conversely, “Riesling wine likers” were generally older with higher wine knowledge. These consumers were interested in the region, vintage and alcohol level when purchasing white wine. The final group (40 percent of the total sample) had a lower liking for Riesling wines, but liked all types relatively highly, had low to moderate wine knowledge and took more note of expert opinion than the other clusters. RESEARCH LIMITATIONS/IMPLICATIONS: The findings of this study can be extrapolated to the South Australian population, however, the sample size may restrict the generalisation of the results to the broader Australian population. ORIGINALITY/VALUE: The results of this study provide initial insights into the behaviour of white wine consumers and highlight the importance of wine knowledge in differentiating consumer liking. Some strategies for influencing consumers’ preference are suggested.

2011-12-31T13:30:00Z Geering, Andrew D. W. Randles, John Wesley http://hdl.handle.net/2440/77620 2013-05-10T05:30:07Z 2011-12-31T13:30:00Z

Title: Virus diseases of tropical crops Author: Geering, Andrew D. W.; Randles, John Wesley Abstract: Virus diseases are serious constraints to the productivity and profitability of a wide range of tropical crops. Identification of the causal viruses and understanding their epidemiology is the key to estimating the incidence and economic impact of the diseases they cause, and to devising virus management strategies. Epidemics result from interactions between virus, host plant, vector and environmental factors, and every epidemic can be considered to be a unique pathosystem in which each of the components contributes to the epidemic, and in which none are limiting. Pathogen diagnosis is the key to managing diseases, and we list 18 crops, their main virus/viroid diseases and pathosystem descriptors for each. Six types of pathosystem are described on the basis of the mode of spread, and the different management strategies applicable to each are discussed. The Ninth Report of the International Committee on Taxonomy of Viruses (2012) is an essential reference for virologists working with tropical crops. Description: eLS formerly known as the Encyclopedia of Life Sciences

2011-12-31T13:30:00Z