田间应用拮抗酵母菌对甜樱桃果实采后病害的防治效果

研究了应用拮抗酵母菌丝孢酵母(Trichosporon pullulans(Lindner.)Diddens et Lodder)、罗伦隐球酵母(Cryptococcus laurentii(Kuffer.)Skinner)和粘红酵母(Rhodotorula glutinis(Fresenius)Harrison)后拮抗菌在果实表面的繁殖能力以及对不同贮藏条件下甜樱桃(Pranus avivum L.cv.Hongdeng)果实采后病害的防治效果。酵母菌的使用浓度为1×10~8CFU/mL。结果表明,田间3种拮抗菌都能够在果实表面增值,但是只有C.laurentii和R.glutinis能够持续稳定地生长。C.laurentii的抑病效果最好,它对田间环境和采后低温低氧及高CO_2都具有很强的适应能力。     

三种拮抗酵母菌对苹果采后青霉病的抑制效果

从苹果果实上分离获得的50余种酵母菌中筛选出了能够有效地抑制苹果青霉病(Penicilium expansum Link)的丝孢酵母(Trichosporon pullulans (Lindner.) Diddens and Lodder)、罗伦隐球酵母(Cryptococcus laurentii (Kuffer.) Skinner)和粘红酵母(Rhodotorula glutinis (Fresen.) F. C. Harrison).其中,抑病效果最好的T. pullulans 是一种用于采后果实生物防治的新型拮抗菌.研究了这三种拮抗菌不同浓度处理和外加营养物质以及与钙配合使用对苹果青霉病的抑病效果.实验结果表明:酵母菌浓度越高,抑病作用越强;外源营养物质的加入削弱了酵母菌的拮抗效果;在C. laurentii的细胞悬浮液中加入0.18 mol/L 的CaCl2能显著提高其抑病能力,但增加CaCl2 对T. pullulans 和R. glutinis 的抑病效果却没有明显作用.     

三种拮抗酵母菌对苹果采后青霉病的抑制效果

从苹果果实上分离获得的50余种酵母菌中筛选出了能够有效地抑制苹果青霉病（Peniclium expansum Link)的丝孢酵母（Trichosporon pullulans(Lindner.)Diddens and Lodder)。罗伦隐球酵母（Cryptococcus laurentii(Kuffer.)skin-ner)和粘红酵母（Rhodotorula glutinis(Fresen.)F.C.Harrison)。其中,抑病效果最好的T.pullulans是一种用于采后果实生物防治的新型拮抗菌,研究了这三种拮抗菌不同浓度处理和外加营养物质以及与钙配合使用对苹果青霉病的抑病效果。实验结果表明;酵母菌浓度越高,抑病作用越强;外源营养物质的加入削弱了酵母菌的拮抗效果;在C.laurentii的细胞悬浮液中加入0.18mol/L的CaCl2能显著提高其抑病能力。但增加CaCl2对T.pullulans和R.glutinis的抑病效果却没有明显作用。     

丝孢酵母与钙和杀菌剂配合对苹果采后病害的抑制效果(英文)

研究一种从桃果实上分离获得的拮抗菌———丝孢酵母 (Trichosporonsp .)对苹果 (MalusdomesticaBorkh .)采后病害的防治效果 ,包括接种不同浓度的拮抗菌与不同病菌之间的拮抗作用 ,以及拮抗菌与钙或与杀菌剂配合对苹果灰霉病和青霉病的抑制效果。结果表明 ,拮抗菌和病菌孢子的浓度都明显地影响其抑菌效果。拮抗菌的使用浓度越大 ,病菌孢子的接种浓度越低 ,其抑病效果越好。当丝孢酵母菌的使用浓度达到 10 8colony_formingunits(CFU) /mL时 ,可完全抑制接种在苹果上的灰霉菌 (BotrytiscinereaPers.)和青霉菌 (Penicilliumexpansum (Link)Thom)(<10 6spores/mL)的致病力。用 10 6～ 10 7CFU/mL的丝孢酵母与 5 0 μL/L的扑海因配合对苹果采后灰霉病和青霉病的抑制效果明显地好于单独使用相同剂量的拮抗菌或杀菌剂。在丝孢酵母的悬浮液中加入 1%～ 2 ?Cl2 可显著地提高拮抗菌对灰霉病和青霉病的抑制效果。     

丝孢酵母与钙与杀菌剂配合对苹果采后病害的抑制效果

研究一种从桃果实上分离获得的拮抗菌－丝孢酵母（Trichosporon sp.)对苹果（Malus domestica Borkh.)采后病害的防治效果,包括接种不同浓度的拮抗菌与不同病菌之间的拮抗作用,以及拮抗菌与钙或与杀菌剂配合对苹果灰霉病和青霉病的抑制效果。结果表明,拮抗菌和病菌孢子的浓度都明显地影响其抑菌效果。拮抗菌的使用浓度越大,病菌孢子的接种浓度越低,其抑病效果越好。当丝孢酵母菌的使用浓度达到1068colony-forming units(CFU)mL时,可完全抑制接种在苹果上的灰霉菌（Botrytis cinerea Pers.)和青霉菌（Penicillium expansum(Link)Thom)的抑制效果明显地好于单独使用相同剂量的拮抗菌或杀菌剂。因丝孢酵母的悬液液中加入1％－2％CaCl2可显地提高拮抗菌对灰霉病和青霉病的抑制效果。     

拮抗菌Pichia membranefaciens与病原菌Rhizopus stolonifer在桃果实伤口处的拮抗作用

膜醭毕赤酵母 (PichiamembranefaciensHansen)是本实验室从果实上分离获得的一种能有效防治桃果实采后软腐病的拮抗菌。本文将P .membranefaciens与葡枝根霉 (Rhizopusstolonifer)在桃果实伤口部位共培养 2 4h后 ,用扫描电子显微镜观测了它们的拮抗作用。结果表明 ,在有病原菌的地方聚集了大量的酵母拮抗菌 ,而且拮抗菌紧密地吸附在病原菌的菌丝体上。结合以前的研究结果可以推断 ,P .membranefaciens主要通过与病原菌进行营养和空间的竞争 ,紧密地吸附在病原菌菌丝体上分泌能降解病原菌细胞壁的水解酶 (如几丁质酶和 β_1,3_葡聚糖酶 ) ,并可能诱导寄主产生抗性 ,从而抑制桃软腐病的发生。     

毕赤酵母G5拮抗葡萄灰霉病机理初探

针对新疆红提葡萄中分离的生防菌株——毕赤酵母G5,以葡萄灰霉菌(Botrytis cinerea)为靶标菌,研究了G5对葡萄灰霉菌孢子及对葡萄果实内5种关键酶活性的影响,初步探讨了G5拮抗葡萄采后灰霉病的机理。采用离体(in vitro)实验与活体(in vivo)实验的方法对毕赤酵母菌G5拮抗葡萄灰霉病的机理进行探究。结果发现,毕赤酵母菌株G5对葡萄灰霉菌孢子的萌发和菌丝生长均有抑制作用,对灰霉菌丝的抑制率最高为80.20%,对灰霉孢子抑制率达86.89%;两者间存在营养竞争关系,有重寄生现象产生,拮抗菌自身并不分泌抗菌物质。此外,该菌株能诱导果实体内过氧化物酶、多酚氧化酶、苯丙氨酸解氨酶、几丁质酶、β-1,3-葡聚糖酶的酶活性,使其酶活性有显著提高,说明毕赤酵母G5可以有效的诱导果实内抗病相关酶的活性,增强对灰霉病的抑制效果。毕赤酵母G5拮抗葡萄灰霉病的机理主要包括营养竞争、诱导抗病性,是否有重寄生作用还需要进一步验证。     

醇化烟叶酵母菌分离鉴定及其生物学特性研究

采用涂布培养法和富集培养法对醇化烟叶样品中酵母菌进行了分离,富集培养法分离到23株,涂布培养法分离到6株。29株酵母菌的生物学特性研究表明,其中果胶酶、蛋白酶、淀粉酶、脂酶、纤维素酶、酚类利用、木质素利用、尼古丁降解、发酵产物气味等试验呈阳性的菌株数分别是1、10、0、3、10、22、1、21和29株。利用ATB系统,将ATY1、ATY8和ATY27等3株酵母菌分别鉴定为黏红酵母(Rhodotorula glutinis)、罗伦隐球酵母(Cryptococcus laurentii)和粗壮假丝酵母(Candida valida),各菌株鉴定结果的符合率分别为99.4%、98.2%和89.9%。研究结果表明,醇化烟叶中酵母菌种群数量较小,但酵母菌的生物学特性有利于烟叶醇化,值得进一步深入研究。     

新疆石河子地区甜樱桃采后腐烂致病真菌的分离鉴定

【背景】甜樱桃果实柔软多汁,采后腐烂率高。石河子是新疆新兴的甜樱桃种植地区之一,但由于采后储运不当造成巨大的经济损失。【目的】鉴定石河子地区的甜樱桃果实腐烂病原菌,以期提高该地区甜樱桃的采后品质、延长货架期。【方法】从石河子136团种植的甜樱桃腐坏组织中分离真菌菌株,根据柯赫氏法则将分离得到的菌株重新接种到健康的甜樱桃果实上确定其致病性;结合形态学和真菌核糖体转录间隔区(r DNA-ITS)序列分析对致病真菌进行鉴定。【结果】从石河子地区甜樱桃腐烂的果肉中分离出5类丝状真菌,其中3类是甜樱桃果实的致病真菌,转录间隔区序列比对确定3类真菌中代表菌株分别为易脆毛霉(Mucorfragilis)、镰刀菌(Fusariumsp.)和干酪青霉(Penicillium camemberti)。【结论】导致新疆石河子地区甜樱桃果实腐烂的致病真菌主要有易脆毛霉(Mucor fragilis)、镰刀菌(Fusarium sp.)和干酪青霉(Penicillium camemberti)。     

余甘子采后软腐病菌的分离鉴定及其细胞壁水解酶活性

【背景】药食同源的余甘子果实在采后贮藏过程中极易软腐变质,严重影响其品质和经济价值。【目的】明确引起余甘子果实软腐病的病原菌种类及其生长特性和产细胞壁水解酶活性,为余甘子采后软腐病的控制及延长其贮藏期奠定基础。【方法】采用组织块分离法从采后发病的余甘子果实分离病原菌,按照科赫法则确定分离菌株的致病性;采用形态学特征结合rDNA-ITS序列分析对病原菌进行鉴定,测定病原菌菌丝生长和产孢特性,检测产胞外细胞壁水解酶活性。【结果】从具有软腐症状的余甘子果实中分离得到32株真菌,其中菌株DQ23是余甘子采后软腐病的致病菌,通过形态特征结合rDNA-ITS序列将其鉴定为Penicillium choerospondiatis。其菌丝在酵母膏葡萄糖琼脂培养基(YDA)上生长最快,在马铃薯蔗糖琼脂培养基(PSA)上产孢最多。该菌能有效利用多种碳、氮源,适宜产孢的碳源为蔗糖、葡萄糖,氮源为蛋白胨、牛肉膏、酵母膏。菌丝生长的最适温度和pH范围分别为25°C和3.0-5.0,产孢的最适温度和pH范围分别为25°C和4.0-7.0。光照均利于菌丝生长和产孢。该菌具有分解果胶、纤维素的能力,无分解蛋白质、鞣质的能力。【结论】Penicillium choerospondiatis是余甘子果实软腐病的病原菌,研究结果为该病害的防控奠定了基础。     

Combination of antagonistic yeasts with two food additives for control of brown rot caused by Monilinia fructicola on sweet cherry fruit

AIMS: To evaluate beneficial effect of two food additives, ammonium molybdate (NH4-Mo) and sodium bicarbonate (NaBi), on antagonistic yeasts for control of brown rot caused by Monilinia fructicola in sweet cherry fruit under various storage conditions. The mechanisms of action by which food additives enhance the efficacy of antagonistic yeasts were also evaluated. METHODS AND RESULTS: Biocontrol activity of Pichia membranefaciens and Cryptococcus laurentii against brown rot in sweet cherry fruit was improved by addition of 5 mmol l(-1) NH4-Mo or 2% NaBi when stored in air at 20 and 0 degrees C, and in controlled atmosphere (CA) storage with 10% O2 + 10% CO2 at 0 degrees C. Population dynamics of P. membranefaciens in the wounds of fruit were inhibited by NH4-Mo at 20 degrees C after 1 day of incubation and growth of C. laurentii was inhibited by NH4-Mo at 0 degrees C in CA storage after 60 days. In contrast, NaBi did not significantly influence growth of the two yeasts in fruit wounds under various storage conditions except that the growth of P. membranefaciens was stimulated after storage for 45 days at 0 degrees C in CA storage. When used alone, the two additives showed effective control of brown rot in sweet cherry fruit and the efficacy was closely correlated with the concentrations used. The result of in vitro indicated that growth of M. fructicola was significantly inhibited by NH4-Mo and NaBi. CONCLUSION: Application of additives improved biocontrol of brown rot on sweet cherry fruit under various storage conditions. It is postulated that the enhancement of disease control is directly because of the inhibitory effects of additives on pathogen growth, and indirectly because of the relatively little influence of additives on the growth of antagonistic yeasts. SIGNIFICANCE AND IMPACT OF THE STUDY: The results obtained in this study suggest that an integration of NH4-Mo or NaBi with biocontrol agents has great potential in commercial management of postharvest diseases of fruit.     

Enhancement of biocontrol activity of yeasts by adding sodium bicarbonate or ammonium molybdate to control postharvest disease of jujube fruits

AIMS: To assess the potential of sodium bicarbonate and ammonium molybdate as additives in enhancing the biocontrol efficacy of Rhodotorula glutinis and Cryptococcus laurentii against blue mould in jujube fruits. METHODS AND RESULTS: Two yeasts at a concentration of 107 CFU ml-1, in combination with 238 mmol l-1 sodium bicarbonate or 15 mmol l-1 ammonium molybdate, showed a significant inhibition effect on blue mould of jujube fruits stored at 20 degrees C for 5 days. The colonizing ability of the yeasts in wounded sites was significantly decreased in the presence of ammonium molybdate. CONCLUSIONS: Combining R. glutinis or C. laurentii with sodium bicarbonate or ammonium molybdate provided a more effective control of postharvest disease than using the antagonistic yeasts or the chemicals alone. SIGNIFICANCE AND IMPACT OF THE STUDY: The addition of sodium bicarbonate or ammonium molybdate reduced the number of antagonists required to efficiently control disease of postharvest fruits, which could result in the reduction of costs.     

Photosynthesis and carbohydrate partitioning in sweet cherry: Fruiting effects

The effect of fruiting on carbon fixation and retention in leaves was monitored by measuring net photosynthesis (Pn) and total non-structural carbohydrates (TNC) on a seasonal basis on mature fruiting and non-fruiting sweet cherry trees ( Prunus avium L. cv. Bing). Pn was also measured diurnally during stages II and III of fruit development. Pn rates increased to between 18 and 20 mg CO₂ dm^-2 h^-1 during stage II of fruit development and were maintained until harvest. Diurnally, Pn increased in the morning to 20 mg CO₂ dm^-2 h^-1 and this rate continued until sunset. Leaf carbohydrate levels decreased in both fruiting and non-fruiting trees beginning at the equivalent of stage II of fruit growth. Carbohydrates were lower in leaves and woody portions of current, 1- and 2-year-old shoots of fruiting trees. Although differences were found in levels of non-structural carbohydrates, no differences in Pn were found in fruiting vs non-fruiting plants on either a seasonal or a diurnal basis. Pn rates in swet cherry in the field were primarily affected by ontogeny and environment and not by sink strength.     

Differences in body size and egg loads of Rhagoletis indifferens (Diptera: Tephritidae) from introduced and native cherries

The western cherry fruit fly, Rhagoletis indifferens Curran, infests introduced, domesticated sweet [Prunus avium (L.) L.], and tart cherries (Prunus cerasus L.) as well as native bitter cherry, Prunus emarginata (Douglas) Eaton. Bitter cherries are smaller than sweet and tart cherries and this could affect various life history traits of flies. The objectives of the current study were to determine 1) if body size and egg loads of flies infesting sweet, tart, and bitter cherries differ from one another; and 2) if any observed body size differences are genetically based or caused by the host fruit environment. Pupae and adults of both sexes reared from larval-infested sweet and tart cherries collected in Washington and Montana were larger than those reared from bitter cherries. In addition, flies of both sexes caught on traps in sweet and tart cherry trees were larger than those caught in bitter cherry trees and females trapped from sweet and tart cherry trees had 54.0-98.8% more eggs. The progeny of flies from naturally-infested sweet and bitter cherries reared for one generation in the laboratory on sweet cherry did not differ in size. The same also was true for progeny of sweet and bitter cherry flies reared in the field on bitter cherry. The results suggest that the larger body sizes of flies from sweet and tart cherries than bitter cherries in the field are caused by host fruit and not genetic factors.     

Influence of pesticides on yeasts colonizing leaves

The effect of nine different pesticides on the growth of yeasts isolated from the leaves of fruit and forest trees was investigated. Four insecticides (with the active ingredients: thiacloprid, deltamethrin, lambdacyhalothrin, and thiamethoxam) and five fungicides (with the effective substances: bitertanol, kresoxim-methyl, mancozeb, trifloxystrobin, and cupric oxychloride) were tested. The concentrations of chemicals were those recommended by the manufacturers for the spraying of trees. The yeast strains isolated from the leaves of fruit trees were not sensitive to any of the insecticides. The majority of yeast strains isolated from the leaves of forest trees were either not sensitive or only to a small extent. While Rhodotorula mucilaginosa and Pichia anomala were not affected by any insecticide, the strains of Cryptococcus laurentii and Rhodotorula glutinis showed the highest sensitivity. The effects of fungicides on the growth of isolated yeasts were more substantial. The fungicide Dithane DG (mancozeb) completely inhibited the growth of all yeasts. All strains isolated from fruit tree leaves were more resistant to the tested fungicides than those isolated from the leaves of forest trees. The most resistant strains from the leaves of fruit trees belonged to the species Metschnikowia pulcherrima, Pichia anomala, and Saccharomyces cerevisiae, whereas Cryptococcus albidus and C. laurentii, originating from the leaves of forest trees, showed the highest sensitivity to fungicides.     

Effects of a biocontrol agent and methyl jasmonate on postharvest diseases of peach fruit and the possible mechanisms involved

AIMS: To investigate effects of application of 200 micromol l(-1) methyl jasmonate [MeJA (200)] and Cryptococcus laurentii alone or in combination against postharvest diseases (Monilinia fructicola and Penicillium expansum) in peach fruit stored at 25 and 0 degrees C, and to evaluate the possible mechanisms involved. METHODS AND RESULTS: The efficacy of controlling postharvest diseases by resistance induced in peach fruit treated with MeJA (200) and C. laurentii alone or in combination and the relationship between activities of defence-related enzymes in peach fruit and lesions caused by M. fructicola and P. expansum were examined. At the same time, the effects of MeJA (200) on the population of C. laurentii in the peach wounds and on the mycelial growth of M. fructicola and P. expansumin vitro were investigated. The results indicated that treatment of peach fruit with C. laurentii at 1 x 10(8) CFU ml(-1) alone, or combining C. laurentii at 5 x 10(7) CFU ml(-1) with MeJA (200) all resulted in a lower lesion diameter of brown rot and blue mould caused by M. fructicola and P. expansum compared with the controls in peach fruit. MeJA (200) enhanced the population of C. laurentii, and inhibited mycelial growth of P. expansum. However, it had a little effect on M. fructicolain vitro. MeJA and C. laurentii alone or in combination induced higher activities of Chitinase, beta-1,3-glucanase, phenylalanine ammonia-lyase and peroxidase (POD) than applying the yeast alone at both 25 and 0 degrees C. CONCLUSIONS: MeJA (200) not only directly inhibited mycelial spread of postharvest pathogens, but also increased population of C. laurentii, which induced stronger disease resistance in fruit than MeJA or yeast alone, and resulted in a lower lesion diameter of brown rot and blue mould caused by M. fructicola and P. expansum. SIGNIFICANCE AND IMPACT OF THE STUDY: MeJA (200) in combination with C. laurentii was beneficial for controlling brown rot and blue mould caused by M. fructicola and P. expansum in peach fruit. The inhibitory mechanism was mainly because of resistance induced in peach fruit by MeJA and C. laurentii. In addition, direct inhibition of MeJA on P. expansum also played a role in controlling blue mould.     

Cherry fruit development: Indoleacetic acid oxidase isoenzymes in the seed

Two anionic indoleacetic acid oxidase isoenzymes were separated by polyacrylamide gel electrophoresis from an acetate buffer (0.2 M, pH 4.0) extract of sour cherry ( Prunus cerasus L. cv. Montmorency) seed. One isoenzyme migrated to Rf 0.25 (I1) and the other to Rf 0.78 (I₂). Isoenzyme I, exhibited hyperbolic kinetics and was found during all three stages of fruit development with the highest levels during early stage II. The isoenzyme I₂ showed sigmoidal kinetics and was found only during stages II and III of fruit growth with highest levels during stage III. The activities of both isoenzymes were markedly enhanced by addition of Mn2+ and 2,4-dichloro-phenol to the reaction mixture. Isoenzyme I, showed higher affinity for indoleacetic acid than isoenzyme I₂. The significance of these isoenzymes in cherry fruit growth is discussed.