Syrah Research Articles

Canopy microclimate and berry composition: The effect of bunch exposure on the phenolic composition of Vitis vinifera L cv. Shiraz grape berries

Studies on the effect of light exposure on specific phenolic compounds of berries from Shiraz vines grown in a hot climate are reported. Berries that had developed on bunches receiving high levels of ambient light generally had the highest relative levels of quercetin-3-glucoside and a lower proportion of their malvidin anthocyanins as the coumarate derivative, compared to berries that had developed on bunches in shaded canopy conditions. The response of total anthocyanin levels to treatment conditions was variable and depended on the degree of bunch shading and the resultant berry temperature. It appears that a high degree of bunch exposure in hot climates is not conducive to optimal anthocyanin accumulation in berries. The interactive effects of light and temperature on berry phenolic content and concentration are discussed.

Differential screening indicates a dramatic change in mRNA profiles during grape berry ripening. Cloning and characterization of cDNAs encoding putative cell wall and stress response proteins.

We used differential screening to isolate ripening-associated cDNAs from a Shiraz grape (Vitis vinifera L.) berry cDNA library. A rapid increase in the mRNA levels of a number of cDNAs not present in unripe fruit occurred in grape berries at the onset of ripening. The putative translation products of some of these clones had homologs in other species that are involved in cell wall structure. These included four proline-rich proteins, a small protein that is similar to the non-catalytic, N-terminal domain of some pectin methylesterases, and two other glutamate-rich proteins. The remainder of the clones encoded putative stress response proteins. These included two thaumatin-like proteins, a metallothionein, a transcription factor, a cytochrome P450 enzyme, and proteins induced by water, sugar, and/or cold stress in other species. Many of the homologs of the grape cDNAs thought to be involved in cell wall structure or stress-related responses also accumulate in a developmental manner in other plants. This may indicate that the grape mRNAs accumulate in response to stresses such as the storage of high concentrations of sugars and rapid cell expansion, or they may accumulate as part of the ripening developmental program.

Effects of the rootstock Ramsey (Vitis champini) on ion and organic acid composition of grapes and wine, and on wine spectral characteristics

The influence of Ramsey, used as rootstock of the scion cvs Muscat Gordo Blanco (syn. Muscat of Alexandria), Shiraz (syn. Syrah), Riesling, Cabernet Sauvignon and Chardonnay, on the characteristics of the grape berries and of wine made from them was investigated, comparing ‘own‐rooted’ and ‘grafted’, and comparing wine fermented as juice (without skins) and must (juice and skins). The study involved the partitioning of K+ within berries, changes in juice K+, malic and tartaric acid through fermentation, wine inorganic ion and organic acid composition, and wine spectral characteristics. K+ concentration was higher in berries from grafted than from own‐rooted for all varieties except Chardonnay, and highest for grafted Shiraz. It was higher in skin than in pulp and seeds. In the pulp, it was highest for grafted Shiraz. K+ concentrations in all ferments using must (i.e. juice plus skins) increased during the initial two days after crushing, with the increase reflecting extraction from skins, being greatest for Shiraz and Muscat Gordo Blanco. Tartaric acid concentration in must also increased during the initial two days after crushing and then decreased. Malic acid concentration was higher in juice of Ramsey‐grafted than own‐rooted vines, especially for Shiraz; concentrations did not change markedly during the initial 12 days of fermentation, except where malo‐lactic fermentation occurred. Wine made from grapes of grafted contained significantly less tartaric and more malic acid than that made from own‐rooted for all varieties and for both fermentation types, with the exception of tartaric acid in wine of Muscat Gordo Blanco fermented as must. Wine made from juice had significantly higher tartaric acid and lower malic acid than that made from must for all varieties except for tartaric acid in wine from grafted Shiraz and malic acid in own‐rooted Chardonnay. Wine had a smaller tartaric acid/malic acid ratio when made from must. Wine pH was positively correlated with K+ but negatively with tartaric acid and with the tartaric acid to malic acid ratio. Overall, Shiraz wine contained highest Cl˜, Na+ and K+ concentrations. Red wines obtained from grafted had higher colour hue, especially those from Shiraz. Wines made from fruit borne on own‐rooted Cabernet Sauvignon had the highest concentration of total anthocyanins, ionised anthocyanins and total phenolics.

Use of Sap-Flow Sensors to Schedule Vineyard Irrigation. II. Effects of Post-Veraison Water Deficits on Composition of Shiraz Grapes

Transpiration rates of Shiraz vines grown on a two wire vertical trellis were measured using sap-fow sensors and used as a basis for applying different levels of post-véraison irrigation. The effect of this differential irrigation on plant water status and grape composition were investigated with responses of vines on the upper and lower wires of the trellis studied separately. The concentration of juice total soluble solids and pH was unaffected by irrigation treatment but the concentration of berry anthocyanins and phenolics, expressed as mg/g berry mass and absorbance units/g berry mass respectively, decreased with increase in water application, mainly due to an increase in berry weight. Predawn leaf water potential was measured from veraison to harvest and the water stress integral (S_ψ) was calculated as an indication of the intensity and duration of water stress in the three irrigation treatments. S_ψ was found to be closely correlated with post-veraison water use and with grape composition.

Firmness and grape berry maturation. Definition of different rheological parameters during the ripening

<p style="text-align: justify;">Mechanical properties of Shiraz and Gamay grape berries were studied in relation with their maturity state using the Penelaup<sup>TM</sup> rheometer. The analysis of the constrains registered during berry crushing with the flat tool of the device, up to the pellicular tearing, allowed the definition of different rheological parameters and the characterisation of mechanical behaviour of grape and its evolution with the degree of ripening. The analysis of the deformability curves shows, independently of the cultivar, that berry behaviour is not elastical except for some berries at the beginning and at the end of the ripening. This behaviour can be characterised by two indexes expressing the curvature sense of deformability curves, the curvature degree in a way reflecting the turgescence state of the grape. Berry firmness was also considered in two different ways: the initial firmness which represents the elasticity coefficient of the fruit at the beginning of the deformation, and the bursting firmness which can be considered as the pellicular elasticity coefficient. Others parameters, as the pellicular strength which can be expressed from the value of the displacement at berry bursting and the energy used for the deformation were also defined. The evolution of these different parameters during ripening confirms that berry softening at the véraison time depends on the cultivar and on environmental conditions as the vintage. The analysis of the evolutions also indicates that pellicular strength is maximum at this crucial period of berry development.</p>

Malolactic Fermentation in Grape Musts by a Genetically Engineered Strain ofSaccharomyces cerevisiae

Malate enters <i>Saccharomyces cerevisiae</i> by simple diffusion. Due to the lack of a malate transporter and the low affinity of the <i>S. cerevisiae</i> malic enzyme, this yeast is unable to degrade malate efficiently. We have constructed a malolactic yeast strain by co-expressing the malate permease gene (<i>mae1</i>) of the fission yeast <i>Schizosaccharomyces pombe</i> and the <i>Lactococcus lactis</i> malolactic gene (<i>mle</i>S) in <i>S. cerevisiae</i>. The recombinant strain of <i>S. cerevisiae</i> transported malate and actively metabolized malate to lactate within three days in Cabernet Sauvignon and Shiraz grape musts at 20°C. The malolactic fermentation in Chardonnay grape must was completed within seven days at 15°C. The efficient degradation of malate in grape musts is important to wineries and the availability of malolactic yeasts will allow the early application of cellar operations for storage and aging of wine.

The coloration of the Shiraz grape berries during their ripening. Relations between the color descriptors, &lt;em&gt;in situ&lt;/em&gt; dynamic and influence of some environmental factors

&lt;p style="text-align: justify;"&gt;The coloration of Shiraz grape berries was studied all along the ripening period using the CR 200 Minolta chromameter. The analysis of the relations between the three chromatic descriptors of the color, luminance (L*), saturation (C) and hue (Ho), shows three distinct phases in the averaged course followed by the color of a standard berry from its unripe and green stade up to its fully ripe and black stade. These three phases are considered as reflecting different steps of the biosynthesis of the berry pigments, particularly that of the polyphenols.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;The first phase concerns the green berries with a constant Ho value near 115 degree , but with a noticeable decrease of the two quasi-linearilly linked C and L* descriptors. The beginning of the C or L* changes could be only attributed to modifications or destruction of green and yellow-green pigments (chlorophylles and carotenoids). In this phase, green unsoftened and softened berries coexist.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;The second phase is characterized by to the great change of Ho from 115 degree to near 25 degree (red evolution of the color), the two others descriptors being continuously decreasing. The color change of this fast and transitory phase is not easily observed by the viticulturist and could be explained by biosynthesis or migration of tanins or proanthocyanidins compounds.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;The third phase, where a new important change of Ho values, from 25 degree to near -100 degree (green-blue evolution of the color), with a slower decrease of C and L*, is explained by the biosynthesis of skin anthocyanidins or by glycosylation of the previously appeared tanins or proanthocyanidins. This phase is really the color inception of berries (classical veraison).&lt;/p&gt;&lt;p style="text-align: justify;"&gt;The &lt;em&gt;in situ&lt;/em&gt; evolution of the color descriptors with time allows the determination of the averaged rate of the color change of Shiraz berries during their maturation: decreases of 1.6 and 6 units by day for L* (or C) and Ho, respectively. High levels of heterogeneities due to berry asynchronism and to individual coloration rates were also observed. Results indicate that these heterogeneities were maximum at the veraison and that the onset of the color change (not seen by the viticulturist) appears fiveteen or twenty days before. Compared with previous results, the first color modification of this cultivar is exactly concomitant with the onset of the softening process and with the thermic constraint also appearing at this period in berries and clusters. The analysis of such coloration dynamics effected in situ on two different cultural situations, modelizing important changes in the vine microclimate parameters, shows that the environmental factors of the vinestock modify the color descriptors values and consecutively, the polyphenol composition of the berries during their development and at the harvest.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;Conclusively, the &lt;em&gt;in situ&lt;/em&gt; use of a chromameter appears as a pertinent way for studying the dynamics and biosynthesis of pigments under the various development or ripening conditions especially for the black grape cultivars.&lt;/p&gt;

Anthocyanin composition and anthocyanin pathway gene expression in grapevine sports differing in berry skin colour

The synthesis of anthocyanins was investigated in six grapevine sports with altered skin colour. Cabernet Sauvignon and Shiraz grapes contained anthocyanin monoglucosides as well as acetylated and coumarylated derivatives, predominantly of malvidin, whereas Pinot Noir grapes contained only anthocyanin monoglucosides. Fruit of some sports arising from varieties with black berries either lacked anthocyanins or had much lower levels than their progenitors. A bud sport of Cabernet Sauvignon (Bronze Cabernet) exhibited a 90% reduction in anthocyanin levels, but an anthocyanin composition similar to that of the normal Cabernet Sauvignon fruit. The fruit of a white-coloured bud sport of Bronze Cabernet did not contain anthocyanins. Coloured berries of sports originating on varieties with white-skinned berries also had lower levels of anthocyanins than black grapes, but like Pinot Noir contained very low levels of acylated anthocyanins. The berries of these sports also varied in the proportions of the different types of 3-monoglucosides they contained. The results suggest that control of 3-monoglucoside synthesis and modification vary in the sports. The expression of six genes from the flavonoid biosynthetic pathway was determined. Some genes were expressed in all grapes, even where little or no anthocyanins accumulated, but expression of the gene encoding a UDP glucose-flavonoid 3-o-glucosyl transferase (UFGT) was only detected in coloured grapes that synthesised anthocyanins. Southern and northern analysis of the white grapes indicated that the UFGT gene was present but was not expressed. Thus the lack of anthocyanins in white-skinned varieties or sports correlates with a lack of expression of the UFGT gene, although the expression of some other flavonoid pathway genes was also decreased.

Analysis of the Expression of Anthocyanin Pathway Genes in Developing Vitis vinifera L. cv Shiraz Grape Berries and the Implications for Pathway Regulation.

Anthocyanin synthesis in Vitis vinifera L. cv Shiraz grape berries began 10 weeks postflowering and continued throughout berry ripening. Expression of seven genes of the anthocyanin biosynthetic pathway (phenylalanine ammonia lyase [PAL], chalcone synthase [CHS], chalcone isomerase [CHI], flavanone-3-hydroxylase [F3H], dihydroflavonol 4-reductase [DFR], leucoanthocyanidin dioxygen-ase [LDOX], and UDP glucose-flavonoid 3-o-glucosyl transferase [UFGT]) was determined. In flowers and grape berry skins, expression of all of the genes, except UFGT, was detected up to 4 weeks postflowering, followed by a reduction in this expression 6 to 8 weeks postflowering. Expression of CHS, CHI, F3H, DFR, LDOX, and UFGT then increased 10 weeks postflowering, coinciding with the onset of anthocyanin synthesis. In grape berry flesh, no PAL or UFGT expression was detected at any stage of development, but CHS, CHI, F3H, DFR, and LDOX were expressed up to 4 weeks postflowering. These results indicate that the onset of anthocyanin synthesis in ripening grape berry skins coincides with a coordinated increase in expression of a number of genes in the anthocyanin biosynthetic pathway, suggesting the involvement of regulatory genes. UFGT is regulated independently of the other genes, suggesting that in grapes the major control point in this pathway is later than that observed in maize, petunia, and snapdragon.

Applications of NMR micro-imaging to the study of water, lipid, and carbohydrate distribution in grape berries

The technique of nuclear magnetic resonance (NMR) micro-imaging has been applied to the study of water, lipid, and soluble carbohydrate distribution in intact grape berries. Conventional1H spin echo images reveal details of berry vascular structure, which can be enhanced by suitable choice of imaging parameters. Change in water distribution during drying can also be observed non-invasively. By means of chemical shift imaging methods, it is possible to image separately the distributions of water, lipid, and soluble carbohydrate (glucose and fructose) in selected berries, with an in-plane resolution of 60 μm. The technique demonstrated concentration of lipid (oil) in the seeds of intact, mature Shiraz grapes, in a relatively narrow zone in the endosperm, next to its interface with the inner layer of the seed coat, although the lipid zone did not extend entirely around the endosperm perimeter. Carbohydrate, consisting mainly of glucose and fructose in approximately equal proportions, was shown to be evenly distributed in the placental and pericarp tissues of mature grapes. In some cases magnetic field distortions due to the presence of air pockets in seeds of Chardonnay grapes and in seed traces of mature Sultana grapes were also present, leading to an artefactual appearance of localised high sugar in the chemical shift images of these berries.

The Contribution of Hydrolyzed Flavor Precursors to Quality Differences in Shiraz Juice and Wines: An Investigation by Sensory Descriptive Analysis

Volatile components liberated by hydrolysis of C-18 reversed phase isolates from <i>Vitis vinifera</i> cv. Shiraz juice were evaluated by sensory descriptive analysis. The isolates were hydrolyzed at pH 3.2 or by treatment with a non-selective glycosidase enzyme. Shiraz juices assigned as high and low 9quality9, each sourced from two regions and sampled in 1988 and 1989, were studied. Wines made from the 1989 juices were also subjected to descriptive analysis. The results showed that for one pair of wines and all but one pair of hydrolysates, the quality differences could be distinguished and quantified. The glycosidic hydrolysates prepared by both methods were found to contribute non-berry attributes to wine such as 9stalky9, 9earthy9, and 9cigar/tobacco9. Wines considered to be of high quality were rated higher in these non-berry attributes than their low quality counterparts, and it may be deduced that glycosidic hydrolysates contain aroma compounds that are important to high quality Shiraz wine.

Malate, Tartrate, Potassium, and Sodium in Flesh and Skin of Shiraz Grapes During Ripening: Concentration and Compartmentation

Analysis of malate, tartrate, potassium, and sodium in Shiraz grape berries during ripening showed large and distinctive developmental differences between pericarp tissues. During ripening, tartrate per berry remained relatively constant in both flesh and skin, but malate per berry declined considerably in the flesh, while at the same time doubling in the skin. Potassium concentration increased in both flesh and skin, especially the latter — in some samples, 40% of the K of ripe berries was contained in the skin. Differential extraction with 80% ethanol showed that tartrate was converted to salt forms as ripening progressed, while malate existed entirely as the free acid in both flesh and skin at all stages. Efflux studies showed that the rate with which tartrate, malate, and K leached from flesh tissue increased as berries ripened, indicating a general increase in membrane permeability. However, efflux from skin was rapid at the initial stages of ripening but slow at midripening and showed differences between the behavior of the anions and K, suggesting compartmentation differences.

Renal transplantation in children less than 5 years of age.

19 young children (less than 5 years old) have received 31 renal transplants from 4 live relatives and 27 cadaver donors. The 2-year allograft survival rate for the patients receiving their 1st allograft from the 4 live donors was 75 +/- 22% while for the patients receiving their 1st allograft from 15 cadaver donors was 26 +/- 11%. 10 children are currently surviving with functioning allographs (7 cadavers and 3 live relatives); 4 have died and 5 are undergoing dialysis after the loss of at least one allograft. Despite the poor allograft survival rate the fact that 7 children are surviving with cadaver allografts indicates that the lack of a living related donor should not prevent transplants in young children.

Effects of Ethylene and 2-Chloroethylphosphonic Acid on the Ripening of Grapes

The effects of ethylene gas, 2-chloroethylphosphonic acid, and the auxin, benzothiazole-2-oxyacetic acid, on the ripening of grapes (Vitis vinifera L.) was investigated. Ethylene hastened the start of ripening of Doradillo grapes when it was aplied for 10 days starting midway through the slow growth phase. 2-Chloroethylphosphonic acid applied to Shiraz grapes showed the same effect, but when it was applied earlier, during the second half of the first rapid growth phase or at the start of the slow growth phase of berry development, it delayed ripening. 2-Chloroethylphosphonic acid and benzothiazole-2-oxyacetic acid delayed the ripening of Doradillo grapes, and ethylene partially reversed the effect of benzothiazole-2-oxyacetic acid. The results demonstrate the importance of the slow growth stage in grape berry development and suggest that an auxin-ethylene relationship may be involved in the regulation of grape ripening.