Genetic variability of 19 isolates of Grapevine leafroll-associated virus 2 (GLRaV-2) from Portug... more Genetic variability of 19 isolates of Grapevine leafroll-associated virus 2 (GLRaV-2) from Portuguese grapevine cultivars was characterized by sequencing the entire capsid protein (CP) gene of the virus. Global phylogenetic analysis of the CP gene, which included nucleotide sequences obtained in this study and complete homologous sequences from GenBank, showed segregation of GLRaV-2 variants from Portuguese isolates into three major phylogroups (PN, 93/955 and H4). The novelty of these phylogenetic results is the evidence of well-supported subdivision within H4 as well as within PN, with subgroup PN3 composed exclusively of variants from a Portuguese isolate. These findings and the genetic analysis of global phylogroups indicate demographic expansion, mainly within PN and 93/955. Because the existence of a mixture of variants from different phylogroups was detected in some of the isolates, a typification assay based on reverse transcription reaction followed by polymerase chain reac...
Trabajo presentado en la Final Conference Progress in Vitis Vinifera diversity evaluation and use... more Trabajo presentado en la Final Conference Progress in Vitis Vinifera diversity evaluation and use, celebrada en Lisboa del 7 al 9 de octubre de 2014.
O vinho de Carcavelos e u, vinho generoso produzido na regiao do mesmo nome, cuja fama remonta ao... more O vinho de Carcavelos e u, vinho generoso produzido na regiao do mesmo nome, cuja fama remonta ao tempo do Marques de Pombal (1699-1702). A regiao vitivinicola de Carcavelos foi demarcada em 1907 e confirmada por Carta de Lei em 1908. Neste trabalho aborda-se, de uma forma resumida, a historia da vinha e do vinho da regiao de Carcavelos, caracterizando-se esta regiao no que diz respeito a delimitacao, solos, clima, castas, superficie viticola e producao. Finalmente, procura-se caracterizar, ampelografica e culturalmente, as castas recomendadas e autorizadas na elaboracao do vinho DOC Carcavelos.
O vinho de Carcavelos e u, vinho generoso produzido na regiao do mesmo nome, cuja fama remonta ao... more O vinho de Carcavelos e u, vinho generoso produzido na regiao do mesmo nome, cuja fama remonta ao tempo do Marques de Pombal (1699-1702). A regiao vitivinicola de Carcavelos foi demarcada em 1907 e confirmada por Carta de Lei em 1908. Neste trabalho aborda-se, de uma forma resumida, a historia da vinha e do vinho da regiao de Carcavelos, caracterizando-se esta regiao no que diz respeito a delimitacao, solos, clima, castas, superficie viticola e producao. Finalmente, procura-se caracterizar, ampelografica e culturalmente, as castas recomendadas e autorizadas na elaboracao do vinho DOC Carcavelos.
Australian Journal of Grape and Wine Research, 2016
Background and Aims Grapevine cultivation has a long tradition in Portugal. Presently, 343 cultiv... more Background and Aims Grapevine cultivation has a long tradition in Portugal. Presently, 343 cultivars are legally accepted for wine production. Two hundred and eighty eight accessions from the Portuguese National Ampelographic Collection (including 27 wild grapevines) were genotyped using single-nucleotide polymorphisms (SNP) and compared with the Instituto de Ciencias de la Vid y del Vino-SNP database to reveal identities, synonymies and homonymies. Methods and Results A set of 48 SNPs was used to profile the 288 accessions and 263 different genotypes were detected. A comparison with the Instituto de Ciencias de la Vid y del Vino-SNP database unveiled 14 new synonymies among Portuguese, Spanish and other international cultivars and confirmed known synonyms and homonyms. Most of the genotyped cultivars are not cultivated in Spain. Clustering using hierarchical and non-hierarchical methods did not reflect the Portuguese geographical viticulture regions. Conclusions New synonyms and homonyms were identified by SNP profiling of the Portuguese grapevine germplasm. Most of the genotyped cultivars are circumscribed to Portugal. Some cultivars are important in the Iberian context. Significance of the Study This study confirmed the uniqueness of the Portuguese grapevine genetic pool and disclosed many new synonyms within the cultivars authorised for wine production in Portugal. This study confirmed the suitability of the 48 SNP set for grapevine profiling. Results will help to manage the Portuguese germplasm and to adjust the Portuguese legal framework on the denomination of the cultivars authorised for wine production.
This work focused on the characterization of the volatile compounds and sensory profile of white ... more This work focused on the characterization of the volatile compounds and sensory profile of white wines produced from three minority grapevine varieties of Portugal namely ‘Malvasia’ (Colares), ‘Verdelho’ and ‘Galego Dourado’. The characterization took place using sensory and gas chromatography analysis. Furthermore, the data obtained were analysed through the use of multivariate analysis, which made it possible to evaluate the similarities and dissimilarities between the varieties. The results obtained show a differentiation of the wines produced from each grapevine variety but above all a differentiation of the two vintages was verified. The results obtained, both from a sensory and a chemical point of view, show an interesting oenological potential of these varieties, but still require further studies, in order to evaluate the influence of climatic effects on the profile of volatile compounds and also on the sensory profile.
The domesticated grapevine spread along the Mediterranean basin from the primary Near East domest... more The domesticated grapevine spread along the Mediterranean basin from the primary Near East domestication area, where the greatest genetic diversity is found in its ancestor, the wild vine populations. Portuguese wild populations are on the southwestern fringe of the distribution of the Vitis vinifera L. ssp. sylvestris (C.C. Gmel.) Hegi in Europe. During the last Glacial Period they became isolated from the previous continuum that had been the territory of wild vine populations. Archaeological remains of domesticated vinifera grapevines in Portugal date back from 795 Before Common Era (BCE) in the lower Tagus river basin. In this work, 258 Portuguese vinifera varieties and sylvestris plants were characterized using 261 single nucleotide polymorphism (SNP) markers. The study of the genetic diversity of this local germplasm, its population structure and kinship, all framed in their historical and geographical backgrounds, revealed a complex network of first-degree relationships, where only Iberian varieties are involved. Some Iberian genotypes, like Alfrocheiro (Bruñal, in Spain), Sarigo (Cayetana Blanca), Mourisco Branco (Hebén), Amaral (Caiño Bravo), and Marufo (Moravia Dulce) are ancestors of a considerable fraction of all the autochthonous analyzed varieties. A part of the diversity developed was mostly local in some cases as shown by the closeness of several varieties (Vinhos Verdes) to the wild cluster in different analyses. Besides, several evidences of introgression of domesticated germplasm into wild vines was found, substantiating the high risk of genetic contamination of the sylvestris subspecies. All these findings together to the known matching between the wild maternal lineage of the Iberian Peninsula and an important number of Portuguese grapevine varieties (chlorotype A), point out that some of these varieties derive, directly or indirectly, from originally local wild populations, supporting the possible occurrence of secondary events of local domestication, or, at least, of an introgression process of wild into cultivated grapevines.
To assess the different origins of Portuguese grapevine varieties, we used six nuclear and four c... more To assess the different origins of Portuguese grapevine varieties, we used six nuclear and four chloroplastidal microsatellites as molecular markers, in order to compare the genetic structure of native wild-vines with native grapevine varieties. Both native subspecies have a great diversity, and a high interrelationship across the six nuclear microsatellites. Although identical numbers of alleles were found in each population, their distribution was different in the vinifera and sylvestris subspecies. Portuguese wild-vines have only chlorotypes A and B; A being the most frequent. The fifty-seven analysed Portuguese varieties have chlorotypes A, B, C, and D. The most frequent was the chlorotype A (75%), followed by D (21%). The results obtained reinforced the idea of Western Europe as having been one of the domestication centres for the grapevine, with contributions from the Eastern European gene pool. The observed genetic structure is a starting point from which to clarify the high ...
The diversity found among the Vitis vinifera L. species allows the production of wines with very ... more The diversity found among the Vitis vinifera L. species allows the production of wines with very different characteristics. The development of platforms suitable for food composition analysis is currently an emerging area. Among these, DNA biosensors have been developed for a wide variety of applications, ranging from food safety to authenticity. The main aim of this work was to study the detection capacity of the DNA-based optical biosensor using different V. vinifera matrices (leaf, must and wine). Genomic DNA was extracted from leaf, must and wine of three V. vinifera varieties and was tested on the long-period grating (LPG) DNA-based biosensor developed within our group. The biosensor was able to distinguish the varieties even using DNA extracted from complex matrices, revealing its potential to be applied in wine authenticity.
This work describes the first molecular characterization of grapevine virus B (GVB) in Portuguese... more This work describes the first molecular characterization of grapevine virus B (GVB) in Portuguese grapevine cultivars. During a routine screening of 44 accessions in the National Collection of Grapevine Varieties (CAN PRT051), 17 were found infected with GVB in DAS-ELISA assays with commercial antibodies. However, only six of the corresponding isolates were successfully amplified using primer pairs described in the literature. The sequence variants (ORF4-3'UTR, 1147 nt) retrieved from these isolates segregated into two phylogenetic groups, which included sequences from complete genomes available in GenBank. The highly discrepant results obtained using serological and RT-PCR-based diagnostic tools led to the design of a primer pair for detection of GVB, which allowed the amplification of a 606-bp GVB-specific fragment from all DAS-ELISA-positive isolates and also revealed the existence of false negatives in the serological testing.
Wine authenticity methods are in increasing demand mainly in Denomination of Origin designations.... more Wine authenticity methods are in increasing demand mainly in Denomination of Origin designations. The DNA-based methodologies are a reliable means of tracking food/wine varietal composition. The main aim of this work was the study of High Resolution Melting (HRM) application as a screening method for must and wine authenticity. Three sample types (leaf, must and wine) were used to validate the three developed HRM assays (Vv1-705 bp; Vv2-375 bp; and Vv3-119 bp). The Vv1 HRM assay was only successful when applied to leaf and must samples. The Vv2 HRM assay successfully amplified all sample types, allowing genotype discrimination based on melting temperature values. The smallest amplicon, Vv3, produced a coincident melting curve shape in all sample types (leaf and wine) with corresponding genotypes. This study presents sensitive, rapid and efficient HRM assays applied for the first time to wine samples suitable for wine authenticity purposes.
ABSTRACT For most of the Portuguese viticultural regions, winegrape production is subject to high... more ABSTRACT For most of the Portuguese viticultural regions, winegrape production is subject to high evaporative demands during dry summer leading to increasingly low soil water availability. As a consequence, grapevines normally suffer severe drought stress, affecting negatively yield, wine quality and consequently farmers’ income. To sustain an economic productivity, irrigation is an important tool in vineyard manage-ment. The objective of this study was to understand how deficit irrigation strategies would influence vine vigour, yield and quality of grapes and wines. During two growing seasons (2008-2009), field grown grapevines (‘Tempranillo’) were studied in southern Portugal. Vines were spur-pruned and trained to a bilateral cordon. Three deficit irrigation treatments were defined, using as reference predawn leaf water potential ((Ψpd): weak water stress (Ψpd<-0.4 MPa); mild water stress (-0.4 MPa>Ψpd>-0.6 MPa); and severe water stress (Ψpd<-0.6 MPa)). All these three treatments were undertaken in traditional tillage. An additional treatment was performed with a cover crop (mild water stress) in order to increase soil moisture depletion in spring, causing an earlier water stress. This last treatment caused a greater reduction on vegetative growth (primary and secondary shoots) and yield. Conversely, an increase of total phenolic compounds was found, probably due to higher sunlight penetration into the canopy. However strong differences were verified between the two years with a reduction in total polyphenols index and anthocyanins content in 2009. This was probably due to negative effect of the very high temperatures during phenolics synthesis. Deficit irrigation treatments also caused significant differences on yield, berry sugar content and total phenolics, as well as in the chromatic and sensorial characteristics of wines. The severe deficit treatment caused defoliation leading to an incomplete maturation and inferior wine quality. On the other hand, the weak deficit treatment originated wines with lower total phenolics. Our results suggest that mild water deficits may benefit fruit composition and wine quality. Furthermore, an earlier water deficit could be a useful strategy to increase the phenolic compounds.
Many mutations affecting berry colour in Vitis vinifera cultivars have been reported. In the Port... more Many mutations affecting berry colour in Vitis vinifera cultivars have been reported. In the Portuguese National Ampelographic Collection at INIA-Dois Portos, an accession was found that exhibits, in some vines and at whole plant level, completely white-skin bunches. Other vines exhibit branches giving rise to only white-skin berries and branches which present, in the same bunch, three different coloured berries (completely blue black or white berries and berries showing longitudinally white or blue black sectors). Genomic DNA was extracted from leaves and berries of all phenotypes and analyzed at six nuclear SSR (Simple Sequence Repeat) loci. The SSR analysis revealed that the fragments amplified (from all plants presenting bud sports) coincided in size with those from the Portuguese blue black-berried cultivar 'Alfrocheiro Preto'. The cultivar ancestry was further confirmed with ampelometric descriptors (OIV, 2007) and phenological observations. We infer that the whiteberried plants are a bud sport arisen in 'Alfrocheiro Preto' through a somatic mutation.
Os trabalhos de selecção massal e clonal da videira desenvolvidos em Portugal nos últimos 30 anos... more Os trabalhos de selecção massal e clonal da videira desenvolvidos em Portugal nos últimos 30 anos conduziram à obtenção de clones de várias castas com elevado potencial genético, actualmente em multiplicação para a produção de materiais base e certificado.
The actual Portuguese Ampelographic Collection was established in 1988 as a result of an extensiv... more The actual Portuguese Ampelographic Collection was established in 1988 as a result of an extensive survey all over the country to collect grapevine accessions in regional collections and in old vineyards. It also contains international references, non vinifera Vitis and rootstocks. Originally aiming at characterization of varieties, solving homonyms and synonyms problems, as well as preserving the overall variability of grapevine existing in Portugal, the sanitary status of the accessions was a minor concern. The lack of efficient diagnostic tools, at that time, for most of the actual known viruses and the uniqueness of a number of the accessions further contributed to the current sanitary situation. Most of the original rationale of the collection was solved and exceed using classical ampelographic methods and molecular ones. Renewing and enlarging the actual collection is a current project, but with a stronger sanitary element aiming at reducing the viruses present. Here we presen...
Grapevine virus A (GVA) is one of the most widespread viruses in vineyards worldwide, known for m... more Grapevine virus A (GVA) is one of the most widespread viruses in vineyards worldwide, known for more than 30 years. GVA is implicated in the rugose wood complex, with several natural insect vectors. Routine detection is done by DAS-ELISA with commercial antibodies. Due to the high genetic heterogeneity of GVA, reliable molecular detection and typification assays have been slow to implement and most strains were discovered on the basis of different symptoms induced in herbaceous hosts. In this scenario investigating the genetic structure of GVA populations infecting field-established grapevines is vital to provide a background to improve detection and functional characterization of GVA variants. From an initial set of 30 isolates retrieved from Portuguese cultivars (CAN PRT051, Dois Portos), nucleotide sequences extending through ORFs 3 to 5 and including the 3’-UTR were obtained from 8 isolates, testing an array of published primers. The phylogenetic analysis revealed the existence ...
Genetic variability of 19 isolates of Grapevine leafroll-associated virus 2 (GLRaV-2) from Portug... more Genetic variability of 19 isolates of Grapevine leafroll-associated virus 2 (GLRaV-2) from Portuguese grapevine cultivars was characterized by sequencing the entire capsid protein (CP) gene of the virus. Global phylogenetic analysis of the CP gene, which included nucleotide sequences obtained in this study and complete homologous sequences from GenBank, showed segregation of GLRaV-2 variants from Portuguese isolates into three major phylogroups (PN, 93/955 and H4). The novelty of these phylogenetic results is the evidence of well-supported subdivision within H4 as well as within PN, with subgroup PN3 composed exclusively of variants from a Portuguese isolate. These findings and the genetic analysis of global phylogroups indicate demographic expansion, mainly within PN and 93/955. Because the existence of a mixture of variants from different phylogroups was detected in some of the isolates, a typification assay based on reverse transcription reaction followed by polymerase chain reac...
Trabajo presentado en la Final Conference Progress in Vitis Vinifera diversity evaluation and use... more Trabajo presentado en la Final Conference Progress in Vitis Vinifera diversity evaluation and use, celebrada en Lisboa del 7 al 9 de octubre de 2014.
O vinho de Carcavelos e u, vinho generoso produzido na regiao do mesmo nome, cuja fama remonta ao... more O vinho de Carcavelos e u, vinho generoso produzido na regiao do mesmo nome, cuja fama remonta ao tempo do Marques de Pombal (1699-1702). A regiao vitivinicola de Carcavelos foi demarcada em 1907 e confirmada por Carta de Lei em 1908. Neste trabalho aborda-se, de uma forma resumida, a historia da vinha e do vinho da regiao de Carcavelos, caracterizando-se esta regiao no que diz respeito a delimitacao, solos, clima, castas, superficie viticola e producao. Finalmente, procura-se caracterizar, ampelografica e culturalmente, as castas recomendadas e autorizadas na elaboracao do vinho DOC Carcavelos.
O vinho de Carcavelos e u, vinho generoso produzido na regiao do mesmo nome, cuja fama remonta ao... more O vinho de Carcavelos e u, vinho generoso produzido na regiao do mesmo nome, cuja fama remonta ao tempo do Marques de Pombal (1699-1702). A regiao vitivinicola de Carcavelos foi demarcada em 1907 e confirmada por Carta de Lei em 1908. Neste trabalho aborda-se, de uma forma resumida, a historia da vinha e do vinho da regiao de Carcavelos, caracterizando-se esta regiao no que diz respeito a delimitacao, solos, clima, castas, superficie viticola e producao. Finalmente, procura-se caracterizar, ampelografica e culturalmente, as castas recomendadas e autorizadas na elaboracao do vinho DOC Carcavelos.
Australian Journal of Grape and Wine Research, 2016
Background and Aims Grapevine cultivation has a long tradition in Portugal. Presently, 343 cultiv... more Background and Aims Grapevine cultivation has a long tradition in Portugal. Presently, 343 cultivars are legally accepted for wine production. Two hundred and eighty eight accessions from the Portuguese National Ampelographic Collection (including 27 wild grapevines) were genotyped using single-nucleotide polymorphisms (SNP) and compared with the Instituto de Ciencias de la Vid y del Vino-SNP database to reveal identities, synonymies and homonymies. Methods and Results A set of 48 SNPs was used to profile the 288 accessions and 263 different genotypes were detected. A comparison with the Instituto de Ciencias de la Vid y del Vino-SNP database unveiled 14 new synonymies among Portuguese, Spanish and other international cultivars and confirmed known synonyms and homonyms. Most of the genotyped cultivars are not cultivated in Spain. Clustering using hierarchical and non-hierarchical methods did not reflect the Portuguese geographical viticulture regions. Conclusions New synonyms and homonyms were identified by SNP profiling of the Portuguese grapevine germplasm. Most of the genotyped cultivars are circumscribed to Portugal. Some cultivars are important in the Iberian context. Significance of the Study This study confirmed the uniqueness of the Portuguese grapevine genetic pool and disclosed many new synonyms within the cultivars authorised for wine production in Portugal. This study confirmed the suitability of the 48 SNP set for grapevine profiling. Results will help to manage the Portuguese germplasm and to adjust the Portuguese legal framework on the denomination of the cultivars authorised for wine production.
This work focused on the characterization of the volatile compounds and sensory profile of white ... more This work focused on the characterization of the volatile compounds and sensory profile of white wines produced from three minority grapevine varieties of Portugal namely ‘Malvasia’ (Colares), ‘Verdelho’ and ‘Galego Dourado’. The characterization took place using sensory and gas chromatography analysis. Furthermore, the data obtained were analysed through the use of multivariate analysis, which made it possible to evaluate the similarities and dissimilarities between the varieties. The results obtained show a differentiation of the wines produced from each grapevine variety but above all a differentiation of the two vintages was verified. The results obtained, both from a sensory and a chemical point of view, show an interesting oenological potential of these varieties, but still require further studies, in order to evaluate the influence of climatic effects on the profile of volatile compounds and also on the sensory profile.
The domesticated grapevine spread along the Mediterranean basin from the primary Near East domest... more The domesticated grapevine spread along the Mediterranean basin from the primary Near East domestication area, where the greatest genetic diversity is found in its ancestor, the wild vine populations. Portuguese wild populations are on the southwestern fringe of the distribution of the Vitis vinifera L. ssp. sylvestris (C.C. Gmel.) Hegi in Europe. During the last Glacial Period they became isolated from the previous continuum that had been the territory of wild vine populations. Archaeological remains of domesticated vinifera grapevines in Portugal date back from 795 Before Common Era (BCE) in the lower Tagus river basin. In this work, 258 Portuguese vinifera varieties and sylvestris plants were characterized using 261 single nucleotide polymorphism (SNP) markers. The study of the genetic diversity of this local germplasm, its population structure and kinship, all framed in their historical and geographical backgrounds, revealed a complex network of first-degree relationships, where only Iberian varieties are involved. Some Iberian genotypes, like Alfrocheiro (Bruñal, in Spain), Sarigo (Cayetana Blanca), Mourisco Branco (Hebén), Amaral (Caiño Bravo), and Marufo (Moravia Dulce) are ancestors of a considerable fraction of all the autochthonous analyzed varieties. A part of the diversity developed was mostly local in some cases as shown by the closeness of several varieties (Vinhos Verdes) to the wild cluster in different analyses. Besides, several evidences of introgression of domesticated germplasm into wild vines was found, substantiating the high risk of genetic contamination of the sylvestris subspecies. All these findings together to the known matching between the wild maternal lineage of the Iberian Peninsula and an important number of Portuguese grapevine varieties (chlorotype A), point out that some of these varieties derive, directly or indirectly, from originally local wild populations, supporting the possible occurrence of secondary events of local domestication, or, at least, of an introgression process of wild into cultivated grapevines.
To assess the different origins of Portuguese grapevine varieties, we used six nuclear and four c... more To assess the different origins of Portuguese grapevine varieties, we used six nuclear and four chloroplastidal microsatellites as molecular markers, in order to compare the genetic structure of native wild-vines with native grapevine varieties. Both native subspecies have a great diversity, and a high interrelationship across the six nuclear microsatellites. Although identical numbers of alleles were found in each population, their distribution was different in the vinifera and sylvestris subspecies. Portuguese wild-vines have only chlorotypes A and B; A being the most frequent. The fifty-seven analysed Portuguese varieties have chlorotypes A, B, C, and D. The most frequent was the chlorotype A (75%), followed by D (21%). The results obtained reinforced the idea of Western Europe as having been one of the domestication centres for the grapevine, with contributions from the Eastern European gene pool. The observed genetic structure is a starting point from which to clarify the high ...
The diversity found among the Vitis vinifera L. species allows the production of wines with very ... more The diversity found among the Vitis vinifera L. species allows the production of wines with very different characteristics. The development of platforms suitable for food composition analysis is currently an emerging area. Among these, DNA biosensors have been developed for a wide variety of applications, ranging from food safety to authenticity. The main aim of this work was to study the detection capacity of the DNA-based optical biosensor using different V. vinifera matrices (leaf, must and wine). Genomic DNA was extracted from leaf, must and wine of three V. vinifera varieties and was tested on the long-period grating (LPG) DNA-based biosensor developed within our group. The biosensor was able to distinguish the varieties even using DNA extracted from complex matrices, revealing its potential to be applied in wine authenticity.
This work describes the first molecular characterization of grapevine virus B (GVB) in Portuguese... more This work describes the first molecular characterization of grapevine virus B (GVB) in Portuguese grapevine cultivars. During a routine screening of 44 accessions in the National Collection of Grapevine Varieties (CAN PRT051), 17 were found infected with GVB in DAS-ELISA assays with commercial antibodies. However, only six of the corresponding isolates were successfully amplified using primer pairs described in the literature. The sequence variants (ORF4-3'UTR, 1147 nt) retrieved from these isolates segregated into two phylogenetic groups, which included sequences from complete genomes available in GenBank. The highly discrepant results obtained using serological and RT-PCR-based diagnostic tools led to the design of a primer pair for detection of GVB, which allowed the amplification of a 606-bp GVB-specific fragment from all DAS-ELISA-positive isolates and also revealed the existence of false negatives in the serological testing.
Wine authenticity methods are in increasing demand mainly in Denomination of Origin designations.... more Wine authenticity methods are in increasing demand mainly in Denomination of Origin designations. The DNA-based methodologies are a reliable means of tracking food/wine varietal composition. The main aim of this work was the study of High Resolution Melting (HRM) application as a screening method for must and wine authenticity. Three sample types (leaf, must and wine) were used to validate the three developed HRM assays (Vv1-705 bp; Vv2-375 bp; and Vv3-119 bp). The Vv1 HRM assay was only successful when applied to leaf and must samples. The Vv2 HRM assay successfully amplified all sample types, allowing genotype discrimination based on melting temperature values. The smallest amplicon, Vv3, produced a coincident melting curve shape in all sample types (leaf and wine) with corresponding genotypes. This study presents sensitive, rapid and efficient HRM assays applied for the first time to wine samples suitable for wine authenticity purposes.
ABSTRACT For most of the Portuguese viticultural regions, winegrape production is subject to high... more ABSTRACT For most of the Portuguese viticultural regions, winegrape production is subject to high evaporative demands during dry summer leading to increasingly low soil water availability. As a consequence, grapevines normally suffer severe drought stress, affecting negatively yield, wine quality and consequently farmers’ income. To sustain an economic productivity, irrigation is an important tool in vineyard manage-ment. The objective of this study was to understand how deficit irrigation strategies would influence vine vigour, yield and quality of grapes and wines. During two growing seasons (2008-2009), field grown grapevines (‘Tempranillo’) were studied in southern Portugal. Vines were spur-pruned and trained to a bilateral cordon. Three deficit irrigation treatments were defined, using as reference predawn leaf water potential ((Ψpd): weak water stress (Ψpd<-0.4 MPa); mild water stress (-0.4 MPa>Ψpd>-0.6 MPa); and severe water stress (Ψpd<-0.6 MPa)). All these three treatments were undertaken in traditional tillage. An additional treatment was performed with a cover crop (mild water stress) in order to increase soil moisture depletion in spring, causing an earlier water stress. This last treatment caused a greater reduction on vegetative growth (primary and secondary shoots) and yield. Conversely, an increase of total phenolic compounds was found, probably due to higher sunlight penetration into the canopy. However strong differences were verified between the two years with a reduction in total polyphenols index and anthocyanins content in 2009. This was probably due to negative effect of the very high temperatures during phenolics synthesis. Deficit irrigation treatments also caused significant differences on yield, berry sugar content and total phenolics, as well as in the chromatic and sensorial characteristics of wines. The severe deficit treatment caused defoliation leading to an incomplete maturation and inferior wine quality. On the other hand, the weak deficit treatment originated wines with lower total phenolics. Our results suggest that mild water deficits may benefit fruit composition and wine quality. Furthermore, an earlier water deficit could be a useful strategy to increase the phenolic compounds.
Many mutations affecting berry colour in Vitis vinifera cultivars have been reported. In the Port... more Many mutations affecting berry colour in Vitis vinifera cultivars have been reported. In the Portuguese National Ampelographic Collection at INIA-Dois Portos, an accession was found that exhibits, in some vines and at whole plant level, completely white-skin bunches. Other vines exhibit branches giving rise to only white-skin berries and branches which present, in the same bunch, three different coloured berries (completely blue black or white berries and berries showing longitudinally white or blue black sectors). Genomic DNA was extracted from leaves and berries of all phenotypes and analyzed at six nuclear SSR (Simple Sequence Repeat) loci. The SSR analysis revealed that the fragments amplified (from all plants presenting bud sports) coincided in size with those from the Portuguese blue black-berried cultivar 'Alfrocheiro Preto'. The cultivar ancestry was further confirmed with ampelometric descriptors (OIV, 2007) and phenological observations. We infer that the whiteberried plants are a bud sport arisen in 'Alfrocheiro Preto' through a somatic mutation.
Os trabalhos de selecção massal e clonal da videira desenvolvidos em Portugal nos últimos 30 anos... more Os trabalhos de selecção massal e clonal da videira desenvolvidos em Portugal nos últimos 30 anos conduziram à obtenção de clones de várias castas com elevado potencial genético, actualmente em multiplicação para a produção de materiais base e certificado.
The actual Portuguese Ampelographic Collection was established in 1988 as a result of an extensiv... more The actual Portuguese Ampelographic Collection was established in 1988 as a result of an extensive survey all over the country to collect grapevine accessions in regional collections and in old vineyards. It also contains international references, non vinifera Vitis and rootstocks. Originally aiming at characterization of varieties, solving homonyms and synonyms problems, as well as preserving the overall variability of grapevine existing in Portugal, the sanitary status of the accessions was a minor concern. The lack of efficient diagnostic tools, at that time, for most of the actual known viruses and the uniqueness of a number of the accessions further contributed to the current sanitary situation. Most of the original rationale of the collection was solved and exceed using classical ampelographic methods and molecular ones. Renewing and enlarging the actual collection is a current project, but with a stronger sanitary element aiming at reducing the viruses present. Here we presen...
Grapevine virus A (GVA) is one of the most widespread viruses in vineyards worldwide, known for m... more Grapevine virus A (GVA) is one of the most widespread viruses in vineyards worldwide, known for more than 30 years. GVA is implicated in the rugose wood complex, with several natural insect vectors. Routine detection is done by DAS-ELISA with commercial antibodies. Due to the high genetic heterogeneity of GVA, reliable molecular detection and typification assays have been slow to implement and most strains were discovered on the basis of different symptoms induced in herbaceous hosts. In this scenario investigating the genetic structure of GVA populations infecting field-established grapevines is vital to provide a background to improve detection and functional characterization of GVA variants. From an initial set of 30 isolates retrieved from Portuguese cultivars (CAN PRT051, Dois Portos), nucleotide sequences extending through ORFs 3 to 5 and including the 3’-UTR were obtained from 8 isolates, testing an array of published primers. The phylogenetic analysis revealed the existence ...
Uploads
Papers by João Brazão