An evaluation of biological and abiotic controls for grapevine powdery mildew. 1. Greenhouse studies

Grapevine powdery mildew, caused by the fungus Erysiphe necator , is a major disease affecting grape yield and quality world-wide. In conventionally-managed vineyards, this disease is controlled mainly by regular application of sulfur and synthetic fungicides; and in organic agriculture, by sulfur and canola-based oils. Health and environmental impacts associated with the use of sulfur, development of resistance to certain synthetic fungicides, and demand for residue-free grapes, all point to a need for effective alternatives to sulfur and synthetic chemicals. Accordingly, seven greenhouse experiments were conducted to evaluate the potential of novel (abiotic) materials, as well as certain biological agents, for controlling powdery mildew. Application of Bacillus subtilis , milk (200 mL/L), whey (30 g/L), canola-based oils (2–4 mL/L) and Ecocarb (potassium bicarbonate, 3 g/L) all reduced the severity of powdery mildew, and in some cases by 96% compared with untreated controls. Such treatments thus offer potential as alternatives to sulfur in organic viticulture if their efficacy can be duplicated under field conditions – the subject of paper 2 in this series (Crisp et al. 2006, Australian Journal of Grape and Wine Research 12 , pp. 203–211).     

Control of grapevine powdery mildew with mineral oil: an assessment of oil concentration and spray volume

DC Tron, a highly refined mineral oil containing patented additives to prevent UV light induced breakdown, was evaluated in vineyards for control of powdery mildew. DC Tron suppressed development of powdery mildew but was not as effective as the conventional fungicide Topas. Of the oil treatments the 1% rate applied in spray volumes of 1000 L/ha was the most efficient. Poor control was achieved with oil rates less than 1% as well as spray volumes less than 1000 L/ha whereas phytotoxicity developed in many cases at concentrations greater than 1% or spray volumes higher than 1000 L/ha. In all oil treatments, powdery mildew developed less in leaves than on bunches. This difference was attributed to poor spray coverage on bunches compared to leaves.     

Spatial variation in response to ‘reduced input’ spray programs for powdery mildew and botrytis identified through whole‐of‐block experimentation

Background and Aims: Previous work has highlighted the utility of the whole‐of‐block approach to viticultural experimentation. Here, we use this approach as a means of evaluating alternative spray programs for managing two economically important grapevine diseases at commercial scale. Methods and Results: Two experiments were conducted in vineyards in the Coal River and Rokeby districts of Tasmania. The first, carried out in a 4.5 ha vineyard planted to Vitis vinifera L. cv. Pinot Noir, sought to evaluate fungicide programs for control of powdery mildew (Erysiphe necator), in particular with a view to reducing the amount of sulphur applied in organic production systems. The second sought to evaluate the benefit (if any) of changing the time of fungicide application from flowering to pre‐bunch closure for the control of botrytis bunch rot (Botrytis cinerea) in a 2.4 ha Chardonnay vineyard. In both cases, treatments were applied to a whole‐of‐block experimental design using commercial spray equipment. Disease severity and the response to the various spray treatments, was spatially variable and related to topographic variation. Botrytis severity was also related to vine vigour. The powdery mildew results supported the retention of sulphur in organic spray programs, while Switch® (Syngenta Group, Basel, Switzerland) applied at pre‐bunch closure in the botrytis experiment reduced disease severity relative to the application at flowering. Spatial variation in the response to the latter treatment, when examined four times pre‐harvest, suggested that secondary spread may not have been an important mechanism for increasing disease severity over time. Conclusions: Consistent with the other work described in this series of papers, we conclude that the whole‐of‐block experimental approach offers both researchers and vineyard managers a means of acquiring more useful information than would be obtained from a conventional plot‐based approach. Significance of the Study: This study highlights the value of collecting spatially distributed data as a means of better understanding the incidence, spread, progression and control of fungal grapevine diseases. As such, it provides a new application for this experimental approach, which enables spatial variability to be used as an experimental tool.     

Molecular strategies to enhance the genetic resistance of grapevines to powdery mildew

The Eurasian winegrape Vitis vinifera has little or no genetic resistance to the major fungal pathogens, powdery mildew ( Erysiphe necator ) and downy mildew ( Plasmopora viticola ). These pathogens were first introduced into French vineyards from North America in the 1800s before spreading to all major grape producing regions of the world. As a result, grape production is highly dependent on the use of fungicides. With the increasing financial and environmental costs of chemical application and the emergence of fungicide-resistant strains, the introduction of natural genetic resistance against these fungal pathogens is a high priority for viticultural industries worldwide. We are utilising a number of different molecular approaches to increase our understanding of the basis of resistance to these important major fungal pathogens and to identify potential new sources of genetic resistance. This review will outline the progress and the potential of each of these different molecular strategies to the generation of fungal-resistant grapevine germplasm.     

Integration of strobilurins and other fungicides for the control of powdery mildew on grapes

The strobilurin fungicides Amistar (azoxystrobin) and Flint (trifloxystrobin) were evaluated in 1999/00 and 2000/01 in programs that included various combinations with Thiovit (sulfur) and Topas (penconazole) for the control of powdery mildew on grapes. In most experiments the application of 6 sprays per season that included Thiovit (3 g/L) followed by various combinations of Topas (0.125 mL/L), Amistar (0.5 g/L), Flint (0.15 g/L) and Thiovit (2 g/L) controlled powdery mildew. Although strobilurins were applied from flowering to after fruit set, the order in which various fungicides were applied had little influence on the level of powdery mildew control. In experiments where the bunch or leaf area diseased was 60% or higher in unsprayed plots, the severity was less than 5% where combinations of Thiovit and Topas with either Amistar or Flint were applied. In one experiment, 3 applications of either Legend (quinoxyfen) or Prosper (spiroxamine) following 2 applications of Thiovit also provided excellent control of powdery mildew. In programs where the application of Amistar and Flint were directly compared, Flint was the most effective fungicide for controlling powdery mildew. In the experiments where downy mildew also developed, Amistar was more effective than Flint in controlling this disease.     

Characterisation,stability and in vitro degradation of microcapsules containing Chinese yak (Poephagus grunniens L.) butter

In this research, microcapsules containing Chinese yak butter (MYB) were prepared by spray drying technique using rice syrup/whey protein isolate/sodium caseinate as wall materials. The physiochemical properties, nutritional value, stability and in vitro digestion behaviour of MYB were analysed. The results indicated that MYB were round‐shaped particles with good flow properties, high microencapsulation efficiency (97.4%) and prolonged shelf life. After rehydration, the reconstituted emulsion was found to be uniform and stable. Results also suggested yak butter (YB) with more kinds of fatty acids and a ω‐3/ω‐6 ratio higher than 0.33 was more nutritional for human consumption than commercial milk powder, and spray drying process had nearly no side effects on nutritional value of YB. In addition, the comparative analysis of leakage behaviour after exposure to different simulated gastrointestinal tract fluids indicated that YB could be efficiently leaked out of MYB except a ratio bound to wall materials.     

Maturation of cleistothecia of Uncinula necator (powdery mildew) and release of ascospores in southern Australia

We paired genetically characterised isolates of U. necator under controlled conditions and raised the resultant cleistothecia to maturity. Progeny were recovered from cleistothecia formed in the glasshouse and growth room 97–110 days after cleistothecial initials were observed.
Cleistothecia collected from naturally infected leaves from vineyards in the Adelaide Plains and Langhorne Creek, South Australia, in March and April (autumn) 1998 and stored in the same vineyards, were induced to release ascospores in the laboratory between March 1998 and February 1999. This paper is the first report of cleistothecia of U. necator releasing ascospores during summer, autumn and winter in southern Australia. Cleistothecia did not require a period of over-wintering in order to release ascospores that infected detached grapevine leaves in vitro . Furthermore, cleistothecia that over-wintered in the field were triggered to release ascospores in the laboratory in spring. Release of ascospores in spring was coincident with observations of ascospore-derived infections in the Waite Campus vineyard, confirming that cleistothecia provide an additional source of primary inoculum for powdery mildew in South Australia. Autumn release of ascospores suggests the possibility that U. necator may complete two sexual generations per year in Mediterranean climates, with consequent increased risks of development of fungicide resistance and changes in pathogenicity.     

Chemical composition and nutritive value of spray dried permeate powder

Reconstituted skimmed milk (10% TS) was ultrafiltered, and the permeate was concentrated threefold by reverse osmosis and then spray dried at different temperatures (145–195° C). The drying conditions had no effect on the moisture content or the major constituents of permeate powder. The powder was mainly lactose (85%) with 6.35460% ash. A small percentage of the lactose in the permeate powder was present as a-lactose. Sodium, potassium and citrate were present in high concentrations nearly equivalent to their average percentage in skimmed milk. The calcium, magnesium and inorganic phosphorus contents of permeate powder were also determined. The thiamine, riboflavin and niacin contents of permeate powder averaged 0.445, 0.947 and 0.729 mg/100 g respectively. The drying temperatures had no effect on the vitamin contents of the powder. The permeate powder had average Fe, Zn, Mn and Cu contents of 94.7, 21.1, 3.1 and 9.5 Fg/100 g respectively.     

Development of a fermented goat's milk containing probiotic bacteria

A set-type fermented milk manufactured from goat's milk was developed. Optimal curd tension was achieved by supplementation of milk with skim milk powder and whey protein concentrate (WPC). Milk was fermented employing a commercial probiotic starter culture (ABT-2), which contained Streptococcus thermophilus ST-20Y, Lactobacillus acidophilus LA-5, and Bifidobacterium BB-12. Supplementation of milk with 3% WPC reduced fermentation time by 2 h due to the increase in viable counts of S. thermophilus and Bifidobacterium by 0.3 and 0.7 log units, respectively. Addition of WPC increased the protein content (1%) as well as potassium and magnesium content (0.3 and 0.02 g kg⁻¹, respectively). Increase of the protein content led to an increase in the apparent viscosity and gel firmness of the product, and at the same time whey syneresis was reduced. As a consequence, the product received a high score for appearance, taste, aroma, texture and overall acceptance.     

Isolation and characterization of whey phospholipids

A freeze-dried whey powder was produced by microfiltration of Cheddar cheese whey. A 0.2-micron ceramic membrane in a stainless steel housing unit was used to concentrate components > 400 kDa present in the whey. The experimental whey powder, derived from Cheddar cheese whey, and a commercial whey powder were subjected to proximate analysis, lipid classes, phospholipid classes, and fatty acid compositional analyses. Commercial whey powder and commercial soybean lecithin were subjected to an alcohol fractionation procedure in an effort to alter the ratio of phosphatidyl choline to phosphatidyl ethanolamine and the functionality of dairy phospholipids. The fractionation procedure produced an alcohol-insoluble fraction containing 84% phosphatidyl ethanolamine, whereas the alcohol-soluble fraction resulted in a decrease in the phosphatidyl choline to phosphatidyl ethanolamine ratio. The commercial whey contained a higher ratio of phospholipids to neutral lipids compared with the experimental whey. The classes of phospholipids present within the two wheys were similar, whereas the experimental whey contained a phosphatidyl choline content twice that of the commercial whey, and the phospholipids composition of both wheys differed from the milk fat globule membrane. Comparison of the phospholipids and fatty acid composition of the wheys with the soy lecithin revealed that although the wheys were similar to each other, they differed from the soy lecithin in both the classes of phospholipids present and in the fatty acid composition. These compositional differences may influence the functionality of whey phospholipids.     

Influence of skimmed milk concentrate replacement by dry dairy products in a low fat set‐type yoghurt model system. I: Use of whey protein concentrates,milk protein concentrates and skimmed milk powder

Ten commercial samples of dry dairy products used for protein fortification in a low fat yoghurt model system at industrial scale were studied. The products employed were whey protein concentratres, milk protein concentrates, skimmed milk concentrates and skimmed milk powder which originated from different countries. The gross chemical composition of these dried products were determined, including polyacrylamide gel electrophoresis (SDS‐PAGE) and isoelectric focusing of the proteins, and minerals such as Na, Ca, K and Mg. Yoghurts were formulated using a skim milk concentrated as a milk base enriched with different dry dairy products up to a 43 g kg⁻¹ protein content. Replacement percentage of skim milk concentrated by dry dairy products in the mix was between 1.49 and 3.77%. Yoghurts enriched with milk protein concentrates did not show significantly different viscosity (35.12 Pa s) and syneresis index (591.4 g kg⁻¹) than the two control yoghurts obtained only from skimmed milk concentrates (35.6 Pa s and 565.7 g kg⁻¹) and skimmed milk powder (32.77 Pa s and 551.5 g kg⁻¹), respectively. Yoghurt fortified with the whey protein concentrates, however, was less firm (22.59 Pa s) and had less syneresis index (216 g kg⁻¹) than control yoghurts. Therefore, whey protein concentrates may be useful for drinking yoghurt production. © 1999 Society of Chemical Industry     

胶体金免疫层析法快速检测配方羊奶粉中的牛β-乳球蛋白

建立了一种可快速检测配方羊奶粉中牛β-乳球蛋白(β-lactoglobulin,β-lg)的胶体金免疫层析检测方法。通过杂交瘤技术制备β-lg单克隆抗体(monoclonal antibody,mAb),半抑制浓度(50% inhibiting concentration,IC₅₀)为5.87 μg/mL。将胶体金标记的β-lg mAb包被于金标垫,β-lg和山羊抗小鼠IgG标记于硝酸纤维素膜(nitrocellulose membrane,NC膜)分别作为检测线(T线)和质控线(C线),开发了可检测β-lg的免疫层析试纸条。该试纸条对β-lg的检测限(limit of detection,LOD)值为50 μg/mL,与其他基质成分均未产生有效交叉反应,对全脂山羊乳粉中掺杂脱脂牛奶粉(nonfat skim milk,NFSM)、脱盐乳清粉(desalted whey powder,DWP)和乳清蛋白粉(whey protein powder,WPP)的LOD值分别为5%、5%和0.1%。运用该方法对9个市售配方羊奶粉进行分析,检测结果与商品化酶联免疫吸附测定(enzyme linked immunosorbent assay,ELISA)试剂盒一致。该方法前处理快速简单,5 min即可裸眼判定结果,可用于配方羊奶粉商品的现场快速检测。     

Comparison of casein micelles in raw and reconstituted skim milk

During the manufacture of skim milk powder, many important alterations to the casein micelles occur. This study investigates the nature and cause of these alterations and their reversibility upon reconstitution of the powders in water. Samples of skim milk and powder were taken at different stages of commercial production of low-, medium-, and high-heat powders. The nature and composition of the casein micelles were analyzed using a variety of analytical techniques including photon correlation spectroscopy, transmission electron microscopy, turbidity, and protein electrophoresis. It was found that during heat treatment, whey proteins are denatured and become attached to the casein micelles, resulting in larger micelles and more turbid milk. The extent of whey protein attachment to the micelles is directly related to the severity of the heat treatment. It also appeared that whey proteins denatured during heat treatment may continue to attach to casein micelles during water removal (evaporation and spray-drying). The process of water removal causes casein and Ca in the serum to become increasingly associated with the micelles. This results in much larger, denser micelles, increasing the turbidity while decreasing the viscosity of the milk. During reconstitution, the native equilibrium between colloidal Ca and serum Ca is slowly reestablished. The reequilibration of the caseins and detachment of the whey proteins occur even more slowly. The rate of reequilibration does not appear to be influenced by shear or temperature in the range of 4 to 40°C.     

烟草白粉病抗性连锁分子标记开发及育种利用

  目的  提高烟草白粉病抗病育种效率,有效防止抗性丢失。  方法  通过烟草种质资源白粉病抗性鉴定获得抗源材料,利用F2和BCF1分离群体进行白粉病抗性遗传规律和分子标记连锁分析,开发与烟草白粉病抗性紧密连锁的分子标记。  结果  获得白粉病抗源材料2份,分别为台烟7号和KE1,其中台烟7号的白粉病抗性符合双基因隐性遗传规律。根据抗感亲本的NtMLO基因的差异开发了分子标记,利用分离群体证明该标记与白粉病抗性共分离,并应用于主栽品种的抗性回交改良。  结论  开发了与烟草Ntmlo白粉病抗性共分离的分子标记,可显著提高烟草白粉病抗病育种效率。      

Small and large deformation rheology and microstructure of κ-carrageenan gels containing commercial milk protein products

The rheological behaviour of commercial milk protein/κ-carrageenan mixtures in aqueous solutions was studied at neutral pH. Four milk protein ingredients; skim milk powder, milk protein concentrate, sodium caseinate, and whey protein isolate were considered. As seen by confocal laser microscopy, mixtures of κ-carrageenan with skim milk powder, milk protein concentrate, and sodium caseinate showed phase separation, but no phase separation was observed in mixtures containing whey protein isolate. For κ-carrageenan concentrations up to 0.5 wt%, the viscosity of the mixtures at low shear rates increased markedly in the case of skim milk powder and milk protein concentrate addition, but did not change by the addition of sodium caseinate or whey protein isolate. For κ-carrageenan concentrations from 1 to 2.5 wt%, small and large deformation rheological measurements, performed on the milk protein/κ-carrageenan gels, showed that skim milk powder, milk protein concentrate or sodium caseinate markedly improved the strength of the resulting gels, but whey protein isolate had no effect on the gel stength.     

Maillard Reaction Products as Encapsulants for Fish Oil Powders

The use of Maillard reaction products for encapsulation of fish oil was investigated. Fish oil was emulsified with heated aqueous mixtures comprising a protein source (Na caseinate, whey protein isolate, soy protein isolate, or skim milk powder) and carbohydrates (glucose, dried glucose syrup, oligosaccharide) and spray‐dried for the production of 50% oil powders. The extent of the Maillard reaction was monitored using L*, a*, b* values and absorbance at 465 nm. Encapsulation efficiency was gauged by measurement of solvent‐extractable fat and the oxidative stability of the fish oil powder, which was determined by assessment of headspace propanal after storage of powders at 35 °C for 4 wk. Increasing the heat treatment (60 °C to 100 °C for 30 to 90 min) of sodium caseinate‐glucose‐glucose syrup mixtures increased Maillard browning but did not change their encapsulation efficiency. The encapsulation efficiency of all heated sodium caseinate‐glucose‐glucose syrup mixtures was high, as indicated by the low solvent‐extractable fat in powder (<2% powder, w/w). However, increasing the severity of the heat treatment of the sodium caseinate‐glucose‐glucose syrup mixtures reduced the susceptibility of the fish oil powder to oxidation. The increased protection afforded to fish oil in powders by increasing the temperature‐time treatment of protein‐carbohydrate mixtures before emulsification and drying was observed irrespective of the protein (sodium caseinate, whey protein isolate, soy protein isolate, or skim milk powder) and carbohydrate (glucose, glucose/dried glucose syrup, or oligosaccharide/dried glucose syrup) sources used in the formulation. Maillard reaction products produced by heat treatment of aqueous protein‐carbohydrate mixtures were effective for protecting microencapsulated fish oil and other oils (evening primrose oil, milk fat) from oxidation.     

Influence of grapevine leafroll associated viruses (GLRaV-2 and -3) on the fruit composition of Oregon Vitis vinifera L. cv. Pinot noir: Phenolics

Some of the 10 known grapevine leafroll associated viruses (GLRaVs) have negative impacts upon vine productivity and grape quality, though these negative influences are dependent on factors such as GLRaV strain, cultivar, clone, rootstock, and vine age. This is the first study to report on GLRaV-2 and GLRaV-3 infected vines, with regard to phenolic compounds, and other fruit maturity indices, of ‘Pinot noir’ grapes, compared to berries from adjacent vines free of GLRaVs (same vineyards). Three different rootstock/scion combinations were included in this study. Clusters were collected for two growing seasons from commercial vineyards in the Willamette Valley of Oregon, and each vine sampled was tested for GLRaV-1, -2, -3 and Rupestris stem pitting-associated virus (RSPaV). All sampled vines were infected with RSPaV. Grapevine leafroll associated virus-infected vines tested positive for GLRaV-2 or GLRaV-3. Overall, fruit infected with GLRaV-2 and -3 had reduced percent soluble solids, decreased individual and total anthocyanins, and increased skin and pulp weight for all three ‘Pinot noir’ rootstock/scion combinations examined. Vitis riparia rootstock/‘Pinot noir’ clone 114 scion combination appeared to be the most sensitive to GLRaV-3 infection, having significant reduction of all five anthocyanins, total phenolics, and total tannins, with an increased cluster weight and 100-berry weight. No clear trends were observed in the polyphenolics analysed.     

Effects of protein from different sources on the characteristics of sponge cakes,rice cakes (apam), doughnuts and frying batters

Sponge cakes containing total substitution of whole egg with egg yolk had the largest volume, best texture, highest moisture, colour and flavour compared with all other cakes. Cakes made with total substitution of other proteins had smaller volumes than the control, while those made with egg white had the lowest moisture. Cakes made with whey powder had the tenderest texture. Doughnuts made with protein other than gluten had reduced oil absorption compared with the control. Doughnuts containing whey or skimmed milk had the most desirable flavour; this may be attributed to the presence of lactose. Gluten doughnuts were most disliked because of their hard texture and pale colour. Doughnuts made with total substitution of whole egg with egg white had good texture and low oil absorption. Skimmed milk powder was best for the expansion and texture of chemically leavened rice cakes (apam), while egg white produced the best expansion for yeast-leavened rice cakes, compared with the other proteins studied. The protein that produced the most desirable textures in yeast-leavened rice cakes in order of merit were skimmed milk powder, egg white and egg yolk. Whey, skimmed milk powder and gluten helped improve the crispiness of frying batters. Ovalbumin did not affect the crispiness but significantly reduced the oil absorption of the frying batters. Addition of proteins other than whey and ovalbumin, increased the oil absorption of frying batters.