Attilio Scienza

Cloning and molecular analysis of structural genes involved in flavonoid and stilbene biosynthesis in grape (Vitis vinifera L.).

Genes involved in flavonoid and stilbene biosynthesis were isolated from grape (Vitis vinifera L.). Clones coding for phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydoxylase (F3H), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin dioxygenase (LDOX) and UDP glucose:flavonoid 3-O-glucosyl transferase (UFGT), were isolated by screening a cDNA library, obtained from mRNA from seedlings grown in light for 48 h using snapdragon (Antirrhinum majus) and maize heterologous probes. A cDNA clone coding for stilbene synthase (StSy) was isolated by probing the library with a specific oligonucleotide. These clones were sequenced and when the putative products were compared to the published amino acid sequence for corresponding enzymes, the percentages of similarity ranged from 65% (UFGT) to 90% (CHS and PAL). The analysis of the genomic organization and expression of these genes in response to light shows that PAL and StSy genes belong to large multigene families, while the others are present in one to four copies per haploid genome. The steady-state level of mRNAs encoded by the flavonoid biosynthetic genes as determined in young seedlings is coordinately induced by light, except for PAL and StSy, which appear to be constitutively expressed.

Evidence of a secondary grapevine domestication centre detected by SSR analysis

Abstract. The origin of the grapevine was investigated with archaeobotanical, cultural and historical data. A primary domestication centre was located in the Near East region but there is no agreement on the existence or role of secondary domestication centres. In this work, PCR-based microsatellite analysis has been applied to study the origin of some Italian cultivated grapevines from in situ direct domestication of the wild autoctonous grapevine. Three different Italian locations in Grosseto, Cosenza and Nuoro were identified for this study, and domesticated grapevine as well as wild local accessions growing in these location, were analysed by SSR markers. Cluster analysis performed on Cosenza and Grosseto samples showed a high value of genetic distance between domesticated and wild accessions. On the contrary two cultivars (Bovale Murru and Bovale Muristellu) recovered in Nuoro (in the Sardinia island) were very close to some wild varieties. This suggests that the latter two cultivars may have originated from wild grapevines and consequently that in this location a secondary grapevine domestication event occurred. Six Lambrusco varieties were also included in this analysis as ancient putative ancestors of the cultivated grapevines. The molecular analysis excluded this hypothesis and suggest Lambrusco as an independent Vitis taxon.

Proteome changes in the skin of the grape cultivar Barbera among different stages of ripening

BackgroundGrape ripening represents the third phase of the double sigmoidal curve of berry development and is characterized by deep changes in the organoleptic characteristics. In this process, the skin plays a central role in the synthesis of many compounds of interest (e.g. anthocyanins and aroma volatiles) and represents a fundamental protective barrier against damage by physical injuries and pathogen attacks. In order to improve the knowledge on the role of this tissue during ripening, changes in the protein expression in the skin of the red cultivar Barbera at five different stages from véraison to full maturation were studied by performing a comparative 2-DE analysis.ResultsThe proteomic analysis revealed that 80 spots were differentially expressed throughout berry ripening. Applying a two-way hierarchical clustering analysis to these variations, a clear difference between the first two samplings (up to 14 days after véraison) and the following three (from 28 to 49 days after véraison) emerged, thus suggesting that the most relevant changes in protein expression occurred in the first weeks of ripening. By means of LC-ESI-MS/MS analysis, 69 proteins were characterized. Many of these variations were related to proteins involved in responses to stress (38%), glycolysis and gluconeogenesis (13%), C-compounds and carbohydrate metabolism (13%) and amino acid metabolism (10%).ConclusionThese results give new insights to the skin proteome evolution during ripening, thus underlining some interesting traits of this tissue. In this view, we observed the ripening-related induction of many enzymes involved in primary metabolism, including those of the last five steps of the glycolytic pathway, which had been described as down-regulated in previous studies performed on whole fruit. Moreover, these data emphasize the relevance of this tissue as a physical barrier exerting an important part in berry protection. In fact, the level of many proteins involved in (a)biotic stress responses remarkably changed through the five stages taken into consideration, thus suggesting that their expression may be developmentally regulated.

Somatic embryogenesis from leaf- and petiole-derived callus of Vitis rupestris

Somatic embryogenesis from leaf- and petiole-derived calli of Vitis rupestris was obtained with an efficiency of 3.2% and 4.2% of plated explants, respectively on two combinations of 6-benzyladenine and 2,4-dichlorophenoxyacetic acid (1/0.1 and 1/1 mgl−1) added to MS medium. Embryogenic callus, embryo subcultures and somatic embryogenesis from somatic embryos were obtained either in the presence of 1 mgl−1 indole-3-acetic acid or 0.1 mgl−1 indole-3-butyric acid added to MS or NN media. Within a 4-month culture, embryo germination occurred at a frequency of 13% of explanted embryos when chilling at 4°C was provided for two weeks and a combination of 6-benzyladenine (1 mgl−1) with indole-3-butyric acid (0.1 mgl−1) was added to NN medium supplemented with casein hydrolysate (250 mgl−1). A higher frequency (51%) was obtained in a longer culture time (9 months) when only indole-3-butyric acid was present in the medium and in absence of chilling.

The arrest of development of abortive reproductive organs in the unisexual flower of Vitis vinifera ssp. silvestris

During the first stages of development, flowers of most dioecious species are hermaphroditic, with their transition to unisexual flowers being the result of the developmental arrest of one set of reproductive organs. In this work, we describe the development of male and female flowers of the dioecious wild grape species Vitis vinifera ssp. silvestris through scanning electron microscopy analysis and cytological observations, focusing our attention on the transition from bisexual to unisexual development. We divide floral development of the wild grape into eight stages. Differences between male and female flowers appear first at stage 6, when the style and stigma start to differentiate in female but not in male flowers. Cytological analysis of the slowly growing abortive pistil of male flowers shows that megagametophyte formation is, surprisingly, not inhibited. Instead of pistil abortion in the male flower, sexual determination is accomplished through programmed death of external nucellus cells and some layers of integumentary cells. Sterility of male structures in female flowers follows a different pattern, with microspore abnormalities evident from the time of their release from the tetrad. Sterile microspores and pollen grains in female flowers display an abnormal round shape, lacking colpi and possessing uniformly thickened cell walls that impede germination.

A New Method for Rapid Extraction of High Quality RNA from Recalcitrant Tissues of Grapevine

A quick, inexpensive, and reliable protocol for the extraction of RNA from grapevine berry skins containing large quantities of polyphenols, procyanidins, and polysaccharides is described. The method involves an extraction step in the presence of ribonuclease inhibitors and compounds that compete with vacuolar contaminants for binding to RNA. After extraction with organic solvents, RNA is bound to a fibrous cellulose matrix and processed to eliminate the remaining contaminants and ribonucleases. Following this method, highly stable RNA, sufficiently pure for northern hybridizations and enzymatic processing, may be obtained from as little as 200 mg of starting amounts of fresh material and without multiple, time consuming precipitations or ultracentrifugation steps. This procedure may also prove useful for extracting RNA from recalcitrant tissues of other plant species. Abbreviations: ATA, aurintricarboxylic acid; CF11, cellulose fibrous medium (type 11); PVPP, polyvinylpolypyrrolidone; RT room temperature; VRC, vanadyl ribonucleoside complex.

The use of AFLP and SSR molecular markers to decipher homonyms and synonyms in grapevine cultivars: the case of the varietal group known as Schiave

Abstract ’’Schiave’’ collectively refers to grapevine cultivars presently grown on the Southern and Northern slopes of the Eastern Alps and bearing different names (Schiava, Trollinger, Rossara, Rossola, Geschlafene, Gansfüsser, Urban and others). Their common origin has been suggested by historic, linguistic and ampelographic considerations. This hypothesis has now been assayed by using more direct approaches based on AFLP and SSR analysis. The present paper shows: (1), that AFLP and SSR give comparable results when used to study genomic similarity among the Schiave grapevine cultivars, and (2) that ’’Schiave’’ is used to group grapevine cultivars that are genetically heterogeneous. In fact, a dendrogram constructed from an AFLP analysis of the 33 best-known Schiave (or correlated) cultivars, shows different, and in some cases relevant, degrees of genomic dissimilarity. The analysed cultivars cluster into at least five taxonomic groups with specific geographic distribution along the valleys of Valtellina, Bergamo and Brescia and those of South Tyrol and Swabia. It is concluded that the common definition ’’Schiave’’ refers to a similar cultivation practice in contiguous regions rather than to a common genetic background.

Analysis of grape berry cell wall proteome: A comparative evaluation of extraction methods

Different methods were tested for the extraction of proteins from the cell wall-enriched fraction (CWEf) obtained from a sample formed by skin and seeds of ripe berries of Vitis vinifera L. cv. Cabernet Sauvignon. The CWEf was isolated using a disruptive approach that involves tissue homogenization and precipitation by centrifugation. To extract proteins, the CWEf was treated with CaCl(2) and LiCl in two successive steps or, alternatively, with phenol. The efficiency of the protocols was evaluated by measuring protein yield and by analyzing two-dimensional gel electrophoresis (2-DE) gels for the highest detectable spot number and the greatest spot resolution. The phenol method was also adopted for the extraction of proteins from the cytosolic fraction (CYf). The comparison of 2-DE reference maps of protein extracts from CWEf and CYf indicated the presence of both common traits and unique characteristics. To survey this aspect some spots detected in both fractions or present in only one fraction were analyzed by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Of the 47 spots identified, some were found to be cell wall proteins, while others were proteins not traditionally considered as localized in the apoplastic space. The data presented here provide initial information regarding the apoplastic proteome of grape berry tissues, but also raise the issue of the technical problems that characterize the isolation of cell wall proteins from these very hardy tissues.

From the cradle of grapevine domestication: molecular overview and description of Georgian grapevine (Vitis vinifera L.) germplasm

Historical information and archaeological and palaeobotanical findings point Georgia, in the South Caucasus, as a cradle for grapevine (Vitis vinifera L.) domestication from its wild form (V. vinifera silvestris Beck.) and subsequent selection and development of varieties with characters suitable for human consumption. The hypothesis of Georgia being a center of domestication, combined with its distance from western countries and the importance of its viticulture and wine production, make Georgian grape germplasm particularly interesting to be investigated under the genetic point of view. Twenty nuclear microsatellite loci were used to genotype 112 Georgian grapevine accessions (V. vinifera sativa Beck.) from germplasm collections and 18 from spontaneous growing plants (V. vinifera silvestris Beck.) found in wild conditions and to compare them to a large international cultivar collection in France. Data analysis shows that Georgian grapevine germplasm has maintained distinctive traits despite arrival of international, foreign varieties and still conserve characteristics of local breeding linked to traditional wine production regions of the country. Results have identified alleles, overall loci, well represented in the Georgian germplasm (cultivated and wild) and absent or poorly represented in other countries, highlighting uniqueness and originality of traits of this viticulture. Moreover, the search for relationships between Georgian and foreign viticulture has evidenced few interesting cases linking the Georgian varieties with Western European ones and with neighboring Caucasian countries, helping to identify the real place of origin in some doubtful cases. In addition, populations or sparse individuals of wild grapevine still preserved in the Georgian natural environments present smaller genetic distances with local cultivars than in other European regions. Principal component analysis (PCA) has also identified special overlapping of the wild compartment with some cultivated varieties. This work provides a highly significant new contribution to applied aspects of Georgian grapevine genetic resources management and use. Uniqueness of the Georgian cultivated grapevine gene pool together with its close relatedness with the wild compartment makes this country a good candidate to address questions regarding domestication and grapevine genetic resource conservation.

Profitability of wine grape growing in the EU member states

The aim of this work is to examine the profitability of European Union wine grape growing by comparing some economic indicators extrapolated from information in the Farm Accountancy Data Network, data banks already widely used to analyse the income of European agricultural holdings. The results show that in recent years the profitability of European wine grape growing has grown overall, but to overcome the current economic crisis and face the challenge of “New World” wine producers, it is necessary to make an effort towards public intervention to increase the profitability of wine farms. In this context, the new reform of wine Common Market Organisation (2008) and new Common Agricultural Policy (2007–2013) aimed at improving the profitability of wine grape growing by reducing production costs, increasing added value of wine, promoting the participation of farmers in food quality schemes, etc.