Populational analysis of Saccharomyces cerevisiae strains from different appellations of origin and grape varieties by microsatellite analysis.

The objective of the present study was to evaluate populational relationships among Saccharomyces cerevisiae strains isolated from some of the Portuguese most important grapevine varieties in different appellations of origin, using polymorphic microsatellites. 
One hundred ninety two grape samples were collected during the 2006 and 2007 harvest season in the Vinho Verde (grape varieties: Arinto, Alvarinho, Avesso, Loureiro, Touriga Nacional) Bairrada (grape varieties: Arinto, Baga, Castelão Francês, Maria Gomes, Touriga Nacional) Alentejo (grape varieties, Aragonês, Trincadeira, Touriga Nacional), Terras do Sado (grape variety Castelão) Bucelas (grape variety Arinto) and Estremadura (grape varieties: Arinto, Aragonês, Castelão, Trincadeira, Touriga Nacional) appellations of origin. From the final stage of spontaneous fermentations, 2820 yeast isolates were obtained, mainly belonging to the species S. cerevisiae. An initial genetic screen, based on mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP) and/or interdelta sequence analysis was followed by microsatellite analysis of strains with unique genetic profiles, using 10 highly polymorphic microsatellites. Our results showed that microsatellite analysis revealed a high resolution populational screen, showing that genetic differences and populational structures among S. cerevisiae populations derived from both “diagnostic” vineyard-, specific alleles and the accumulation of small allele-frequency differences across ten microsatellite loci. Heterozygosity was three to four times lower than the expected value, confirming the strong populational substructuring. The presented large-scale approach shows that each vineyard contains differentiated S. cerevisiae populations, showing the occurrence of specific native strains that can be associated with a terroir. 

Financially supported by the programs POCI 2010 (FEDER/FCT, POCTI/AGR/56102/2004) and AGRO (ENOSAFE, Nº 762).
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Microsatellite analysis reveals populational structures of saccharomyces cerevisiae strains from different appellations of origin and grape varieties

The objective of the present study was to evaluate populational relationships among Saccharomyces cerevisiae strains isolated from some of the Portuguese most important grapevine varieties in different appellations of origin, using polymorphic microsatellites. One hundred ninety two grape samples were collected during the 2006 and 2007 harvest season in the Vinho Verde (grape varieties: Arinto, Alvarinho, Avesso, Loureiro, Touriga Nacional) Bairrada (grape varieties: Arinto, Baga, Castelão Francês, Maria Gomes, Touriga Nacional) Alentejo (grape varieties, Aragonês, Trincadeira, Touriga Nacional), Terras do Sado (grape variety Castelão) Bucelas (grape variety Arinto) and Estremadura (grape varieties: Arinto, Aragonês, Castelão, Trincadeira, Touriga Nacional) appellations of origin. From the final stage of spontaneous fermentations, 2820 yeast isolates were obtained, mainly belonging to the species S. cerevisiae. An initial genetic screen, based on mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP) and/or interdelta sequence analysis was followed by microsatellite analysis of strains with unique genetic profiles, using 10 highly polymorphic microsatellites. Our results showed that microsatellite analysis revealed a high resolution populational screen, showing that genetic differences and populational structures among S. cerevisiae populations derived from both “diagnostic” vineyard-, specific alleles and the accumulation of small allele-frequency differences across ten microsatellite loci. Heterozygosity was three to four times lower than the expected value, confirming the strong populational substructuring. The presented large-scale approach shows that each vineyard contains differentiated S. cerevisiae populations, showing the occurrence of specific native strains that can be associated with a terroirFinancially supported by the programs POCI 2010 (FEDER/FCT, POCTI/AGR/56102/2004

Utilisation d'un robot terrestre pour estimer les caracteristiques de la canopee et le rendement au vignoble

This paper aims to present some results of the EU VINBOT (Autonomous cloud-computing vineyard robot to optimize yield management and wine quality) project focused on vineyard yield estimation. A ground truth evaluation trial was set up in an experimental vineyard with two plots of the white varieties ‘Alvarinho’ and ‘Arinto’, trained on a vertical shoot positioning system and spur pruned. For each varietal plot, six smart points were selected with 10 contiguous vines each. During the ripening period of the 2016 season the vines were manually assessed for canopy dimensions and yield and then scanned by the VINBOT sensor head composed with a 2D laser rangefinder, a Kinect v2 camera and a set of robot navigation sensors. Ground truth data was used to compare with the canopy data estimated by the rangefinder and with the output of the image analysis algorithms. Regarding canopy features (height, volume and exposed leaf area), in general an acceptable fit between actual and estimated values was observed with canopy height showing the best agreement. The regression analysis between actual and estimated values of canopy features showed a significant linear relationship for all the features however the lower values of the R2 indicate a weak relationship. Regarding the yield, despite the significant R2 (0.31) showed by the regression analysis between actual and estimated values, the equation of the fitted line indicate that the VINBOT algorithms underestimated the yield by an additive factor. Our results showed that canopy features can be estimated by the VINBOT platform with an acceptable accuracy. However, the underestimation of actual yield, caused mainly by bunch occlusion, deserves further research to improve the algorithms accuracyN/

A Multicultivar Approach for Grape Bunch Weight Estimation Using Image Analysis

The determination of bunch features that are relevant for bunch weight estimation is an important step in automatic vineyard yield estimation using image analysis. The conversion of 2D image features into mass can be highly dependent on grapevine cultivar, as the bunch morphology varies greatly. This paper aims to explore the relationships between bunch weight and bunch features obtained from image analysis considering a multicultivar approach. A set of 192 bunches from four cultivars, collected at sites located in Portugal and South Africa, were imaged using a conventional digital RGB camera, followed by image analysis, where several bunch features were extracted, along with physical measurements performed in laboratory conditions. Image data features were explored as predictors of bunch weight, individually and in a multiple stepwise regression analysis, which were then tested on 37% of the data. The results show that the variables bunch area and visible berries are good predictors of bunch weight (R2 ranging from 0.72 to 0.90); however, the simple regression lines fitted between these predictors and the response variable presented significantly different slopes among cultivars, indicating cultivar dependency. The elected multiple regression model used a combination of four variables: bunch area, bunch perimeter, visible berry number, and average berry area. The regression analysis between the actual and estimated bunch weight yielded a R2 = 0.91 on the test set. Our results are an important step towards automatic yield estimation in the vineyard, as they increase the possibility of applying image-based approaches using a generalized model, independent of the cultivarinfo:eu-repo/semantics/publishedVersio

Association between Grape Yeast Communities and the Vineyard Ecosystems

The grape yeast biota from several wine-producing areas, with distinct soil types and grapevine training systems, was assessed on five islands of Azores Archipelago, and differences in yeast communities composition associated with the geographic origin of the grapes were explored. Fifty-seven grape samples belonging to the Vitis vinifera grapevine cultivars Verdelho dos Acores (Verdelho), Arinto da Terceira (Arinto) and Terrantez do Pico (Terrantez) were collected in two consecutive years and 40 spontaneous fermentations were achieved. A total of 1710 yeast isolates were obtained from freshly crushed grapes and 1200 from final stage of fermentations. Twenty-eight species were identified, Hanseniaspura uvarum, Pichia terricola and Metschnikowia pulcherrima being the three most representative species isolated. Candida carpophila was encountered for the first time as an inhabitant of grape or wine-associated environments. In both sampling years, a higher proportion of H. uvarum in fresh grapes from Verdelho cultivar was observed, in comparison with Arinto cultivar. Qualitatively significant differences were found among yeast communities from several locations on five islands of the Archipelago, particularly in locations with distinctive agro-ecological compositions. Our results are in agreement with the statement that grape-associated microbial biogeography is non-randomly associated with interactions of climate, soil, cultivar, and vine training systems in vineyard ecosystems. Our observations strongly support a possible linkage between grape yeast and wine typicality, reinforcing the statement that different viti-cultural terroirs harbor distinctive yeast biota, in particular in vineyards with very distinctive environmental conditions.Joao Drumonde Neves is the recipient of a fellowship of the Azorean Government (M321/006/F/2008) and PROEMPREGO. This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI), and by national funds through FCT by the projects FCOMP-01-0124-008775, PTDC/AGR-ALI/103392/2008 and PTDC/AGR-ALI/121062/2010.info:eu-repo/semantics/publishedVersio

Leaf morphoanatomy of portuguese autoctones white grapevine cultivars of different geographical origin

Xth International Terroir Congress, Tokaj, Hungary, 2014The knowledge of grapevine varieties leaf morphoanatomy is an important tool to understand the taxa ability to adapt and produce under biotic and abiotic stresses. Aiming to characterize and discriminate between four white Portuguese grapevine (Vitis vinifera subsp. vinifera) varieties – ‘Alvarinho’ (Al), ‘Arinto’ (Ar), ‘Encruzado’ (En) and ‘Viosinho’ (Vi) - from different Winegrowing Regions (Vinhos Verdes, Lisboa, Dão and Douro, respectively), grown side by side in field conditions -, leaf morphoanatomic characteristics were studied under light (LM) and scanning electron microscopy (SEM). The individual primary leaf area revealed significant differences between all cultivars, with the highest value presented by ‘Arinto’ and the lowest by ‘Viosinho’, while ‘Encruzado’ and “Alvarinho” gave intermediate values. Nevertheless, no significant differences were detected on leaf specific dry weight which can be explained by the quite different mesophyll structure. ‘Arinto’ presented the lowest values for total thickness of the lamina, thickness of palisade and spongy parenchyma. The length and thickness of upper and lower epidermal cells of the four cultivars were similar. Under SEM magnification three types of stomata were identified in all the studied genotypes: sunken, at the same level, and raised above the other epidermal cells. No significant differences were registered between cultivars for same-level and sunken stomata values and for stomatal density. ‘Alvarinho’ showed the highest percentage of total for raised-above stomata and ‘Viosinho’ the lowest values. In conclusion, the data indicate some differences in leaf morphoanatomy between grapevine cultivars. Are these grapevine leaf traits differences – e.g. stomata type and mesophyll structure – involved in the differential behavior observed under field conditions? Further studies are neede

Monoterpenic characterization of white cultivars from Vinhos Verdes appellation of origin (North Portugal)

The monoterpenic composition of Alvarinho, Arinto, Avesso, Azal, Batoca, Loureiro and Trajadura Vitis vinifera cultivars from the Vinhos Verdes region (Portugal), in respect to free volatile compounds as well as glycosidically bound aroma precursors, was determined by GC-MS after adsorption on XAD-2 resin. Eighteen monoterpenic compounds were identified and quantified in the free form and twenty-two compounds in the glycosidically bound form. In the free fraction, the Loureiro variety could be easily differentiated from the other six varieties by the important levels of linalool, above the odor perception threshold. This was in contrast to Alvarinho, Avesso, Arinto, Aza and Trajadura, where geraniol prevailed. The Batoca variety showed a very poor monoterpenic profile in the free form. On the other hand, Alvarinho was the richest variety in respect to the glycosidically bound form, followed by Loureiro. In this fraction, linalool and 3,7-dimethylocta-1,5-dien-3,7-diol were the most abundant compounds in the Loureiro grape cultivar; additionally, the isomer (E)-8-hydroxylinalool was in a higher concentration than (Z)-8-hydroxylinalool (sub-region of Sousa),while for the rest of the varieties the (Z) isomer prevailed.The authors thank the Comissao de Viticultura da Regiao dos Vinhos Verdes - EVAG. Divisao de Vitivinicultura e Fruticultura da Direccao Regional de Agricultura de Entre Douro e Minho - DVF-DRAEDM for providing the grape samples for this study. Thanks to Dr. Vilanova (Mision Biologica de Galicia - CSIC, Spain) and Dr. Solange I. Mussatto (University of Minho) for their help in the revision of the manuscript

Anatomia da folha de cultivares brancas de videira com distinta origem geográfica

This study aims to compare the leaf morphoanatomical characteristics of seven Vitis vinifera subsp. vinifera white cultivars with different geographical origin, grown side by side at the same “terroir”. The leaf morphoanatomical traits analyzed under light and scanning electron microscopy (SEM) showed large variability among genotypes. Significant differences between cultivars were observed in single leaf area, specific leaf area, leaf density and in the thickness of cuticle, upper and lower epidermal cells and mesophyll. Leaf dry mass per area presented a significant positive correlation with leaf density but showed no correlation with leaf thickness, results that can be explained by the quite different mesophyll structure, epidermal cells and cuticle thickness. ‘Alvarinho’, ‘Encruzado’, ‘Macabeu’ and ‘Viosinho’ were the cultivars with the highest thickness of cuticle and mesophyll tissues. Under SEM magnification three types of stomata were identified: sunken, at the same level and raised above, with the same level type presenting the higher percentage in all cultivars. Stomata density presented significant differences between cultivars, with ‘Macabeu’ showing the highest value and ‘Alvarinho’ and ‘Arinto’ the lowest ones. The hairs on the lower surface presented a similar woolly aspect in all cultivars. Calcium oxalate crystals, raphids and druses were visible and widely distributed in the parenchyma tissues. The observed differences in leaf traits among genotypes suggest a major role of leaf anatomy in determining grapevine capacity for coping with different environmental conditionsinfo:eu-repo/semantics/publishedVersio

Understanding the need of SO2 in wine according to grape varieties

The use of sulfur dioxide (SO2) is widely accepted as a useful aid in winemaking. It is used as a preservative due to its antioxidant and antimicrobial properties in wine. Although SO2 is a by-product of fermentation, most of the SO2 present in wines is added by the winemaker at different stages of the process. There is still controversy about the use of SO2 and its real impact on consumer health. Since 2005, the EU has required an indicative warning that there are sulfites in the product because a small minority of people are highly allergic to sulfites. However, information is scarce whether the SO2 requirement depends on the wine variety and to what extent. Furthermore, the search for replacers for this enological aid, while maintaining the quality of the final product has not yet been presented, behaving with the same multiplicity of actions. For this reason, SO2 is still one of the most effective tools winemakers has to protect wine and influence flavor. Thus, in this work one studied the volatile organic composition (VOC) of several varieties of wine obtained with controlled addition of different SO2, as well as its substitution or co-addition with ascorbic acid. Headspace solid phase microextraction gas chromatography/mass spectrometry (HS-SPME-GC/MS) was used for VOC analysis. To obtain a more comprehensive characterization of these wines, amino acid (AAs) profiles were accessed through High Performance Liquid Chromatography with Diode Array Detector (HPLC-DAD). The reduction of SO2 during the fermentation of the same must, resulted in different wines and the differences observed depend on the grape varieties used. This differentiation was observed shortly after the first 24 H of fermentation. However, these differences were reduced during stor-age. The same behavior was verified for ascorbic acid, which generally resulting in final products with different VOCs profiles. The results obtained indicate that any reduction in SO2 will interfere with the VOCs profile of the resulting wine, and thus may interfere with their flavor profile. The use of ascorbic acid as a substitute or co-additive did not lead to wines with the same profile as the wines treated only with SO2. Therefore, the use of these enological aids must be wisely considered as it will impact the final product.O uso de dióxido de enxofre (SO2) é amplamente aceite como um auxiliar útil na vinificação. É usado como conservante devido às suas propriedades antioxidantes e antimicrobianas no vinho. Embora o SO2 seja um subproduto da fermentação, a maior parte do SO2 presente nos vinhos é adi-cionado pelo enólogo em diferentes etapas do processo. Ainda há controvérsias sobre o uso do SO2 e seu real impacto na saúde do consumidor. Desde 2005, a UE exige um aviso indicativo de que há sulfitos no produto porque uma pequena minoria de pessoas é altamente alérgica a sulfitos. No en-tanto, a informação é escassa se a exigência de aplicação de SO2 depende da variedade do vinho e em que medida. Além disso, a produra de alternativas para o uso desse auxíliar enológico, manten-do a qualidade do produto final ainda não foi apresentada, actuando com a mesma multiplicidade de ações. Por esta razão, o SO2 ainda é uma das ferramentas mais eficazes que os vinicultores têm para proteger o vinho e influenciar o sabor. Assim, neste trabalho estudou-se a composição orgânica volátil (COV) de diversas castas de vinho obtidas com adição controlada de diferentes SO2, bem co-mo a sua substituição ou co-adição com ácido ascórbico. Recurreu-se a cromatografia gasosa de microextração em fase sólida em espaço de cabeça/espectrometria de massa (HS-SPME-GC/MS) foi usada para análise de COV. Para obter uma caracterização mais abrangente desses vinhos, os perfis de aminoácidos (AAs) foram analisados por meio de Cromatografia Líquida de Alta Eficiência com Diodo Array Detector (HPLC-DAD). A redução de SO2 durante a fermentação de um mesmo mosto, resultou em vinhos diferentes e as diferenças observadas dependem das castas utilizadas. Esta diferenciação foi observada logo após as primeiras 24 H de fermentação. No entanto, essas diferenças foram reduzidas durante o armazenamento. O mesmo comportamento foi verificado para o ácido ascórbico, que geralmente resulta em produtos finais com diferentes perfis de COVs. Os resultados obtidos indicam que qual-quer redução de SO2 irá interferir no perfil de COVs do vinho resultante, podendo assim interferir no seu perfil aromático. A utilização de ácido ascórbico como substituto ou co-aditivo não conduziu a vinhos com o mesmo perfil dos vinhos tratados apenas com SO2. Portanto, o uso desses auxiliares enológicos deve ser considerado com sabedoria, pois afetará o produto final

Protein haze formation in wines revisited. The stabilising effect of organic acids

The effect on the wine protein haze potential of five organic acids commonly encountered in wines (L(+)- tartaric, L( )-malic, citric, succinic and gluconic acids) was assessed. All five acids, tested at 20 mM, reduced dramatically the haze potential of proteins, either in wine or dissolved in water, throughout the range of pH values typical of wines (i.e., from 2.8 through 3.8). Subtle differences among the acid effects did not correlate with the number of their carboxyl groups, but were attributed to electrostatic interactions that depend upon the acid pKa values, the protein pI values and the medium pH. These results invalidate or question the validity of all experiments on wine proteins involving wine model solutions containing organic acids. Overall, the results obtained in the present work clearly indicate that organic acids with a common occurrence in wines exhibit a stabilising effect upon the haze potential of the wine proteins