重寄生菌白粉寄生孢的致病性研究

 在离体条件下,选择了6种白粉菌和49个白粉寄生孢(Ampelomyces quisqualis)菌株进行致病性测定,结果表明,白粉寄生孢菌株之间存在致病性分化且差异极显著,致病性分化主要与寄主真菌和寄主植物有关,而与地理来源相关性不大。研究同时表明,白粉寄生孢有一定的寄生专化性。     

白粉寄生孢生物学特性及其生防应用研究进展

白粉寄生孢Ampelomyces quisqualis是寄生在白粉菌上的一种重寄生菌,作为白粉菌的生防因子,一直受到人们普遍关注。本文从白粉寄生孢的生物学形态、分类、寄主范围、最佳生长条件、分离鉴定以及生防效果和应用前景等方面进行论述,提出了目前白粉寄生孢研究中存在的一些问题以及今后的研究重点,并对白粉寄生孢的生防效果及应用前景进行讨论。     

草莓品种对白粉病菌抗性的组织病理学研究

以4个生产上主栽草莓品种为试材,采用曲利苯兰透明染色法,系统研究了草莓白粉病菌在不同抗性草莓品种上侵染过程的组织学特征。结果表明,草莓白粉病菌的侵染过程可分为：分生孢子萌发、附着胞形成、侵入寄主产生吸器、菌丝扩展和分生孢子链产生。而草莓不同品种对白粉菌的抗性表现在附着胞产生后的各侵染阶段,随品种抗病性增强,病菌侵入率降低,吸器数目减少,菌丝扩展缓慢,分生孢子数目减少。     

白粉病菌重寄生物——粉霉芽枝孢

寄生于枫杨白粉病菌上的重寄生物,经过调查研究,确定为芽枝孢(Cladosporium)的一个种。经与近似的重寄生芽枝孢比较,存在形态上和培养特性方面的区别,因此,确定应另立新种,称为粉霉芽枝孢(C.erysiphicola sp.nov.)。该菌不但能寄生于枫杨白粉病菌上,还能侵染枸杞白粉病菌及小麦白粉病菌等。对上述几种白粉病菌分生孢子的侵染,出现穿入孢子、缠绕菌丝、腐蚀孢子及使孢子萎缩等现象,有希望作为一种生物防治剂。该菌在培养基PSA及PDA上生长繁殖良好,其分生孢子除在不同营养液中萌发外,在蒸馏水中也能萌发。萌发的温度在27℃左右。     

桑里白粉病菌重寄生真菌的分离与鉴定

为了解桑里白粉病菌的重寄生真菌种类,通过分离和寄生性验证,获得2个桑里白粉病菌重寄生真菌菌株HP8和HP9,这两个菌株寄生闭囊壳后,子囊及子囊孢子溃解。菌株HP8菌落绿色,菌丝体无色至褐色,菌丝有隔膜,分生孢子梗结节状膨大,分生孢子椭圆形、单胞、褐色或无色,ITS序列（MT463536）与尖孢枝孢Cladosporium oxysporum（MF135506）同源性为100%,系统进化树分析发现菌株HP8与尖孢枝孢（MF135506）聚在一起;菌株HP9菌落白色,菌丝无色,分生孢子月牙形、单胞、无色,ITS序列（MT463537）与刀孢蜡蚧菌Lecanicillium psalliotae（KC881072）同源性为99%,在系统进化树中,菌株HP9与刀孢蜡蚧菌（KC881072）聚在一起。结合形态特征和ITS序列分析,鉴定出菌株HP8和HP9分别为尖孢枝孢和刀孢蜡蚧菌。高通量测序结果表明,病桑叶在室内保存4个月后,桑里白粉病菌的重寄生真菌为刀孢蜡蚧菌。     

秦岭地区白粉寄生孢的自然分布和生物学特性

为了明确我国秦岭地区白粉菌寄生孢的资源状况并进一步筛选开发对植物白粉病具有生防潜力的菌株,作者于2002～2003年对秦岭地区陕西境内的秦岭北坡、渭河两岸及渭北旱原三个不同生境内白粉菌侵染植株标样上的白粉寄生孢Ampelomyces quisqualis进行了自然分布和生物学特性研究。在白粉菌侵染的旋花科、伞形科、唇型科、菊科、车前科、蓼科、十字花科、豆科、鸭跖草科、凤仙花科、葫芦科、锦葵科、玄参科、蔷薇科、大戟科、茄科、卫矛科、葡萄科、木通科、槭树科、蝶形花亚科等21科(亚科)植物的1145份标样中发现白粉寄生孢菌株39个。白粉寄生孢分离菌株在不同温度、pH值、碳及氮源等条件下的生物学特性测定结果表明:温度为20℃,pH为6.0,采用葡萄糖作碳源及L-甘氨酸作氮源时菌株生长较好。调查结果显示秦岭地区有丰富的白粉寄生孢自然资源,可以进行开发利用,同时生物学特性测定显示出其存在的多种生理类群也为进一步从分子角度研究白粉寄生孢遗传机制,进而从大量菌株中开发用于防治白粉菌的生防制剂提供依据。     

白粉寄生孢不同菌株对控制黄瓜和苹果自粉病病菌的试验研究

为了筛选出更好的能控制白粉病病菌的白粉寄生孢生防菌株,将白粉寄生孢不同菌株对黄瓜白粉病病菌和苹果白粉病病菌分别进行了生防测定.结果显示,白粉寄生孢不同菌株对白粉病病菌的寄生效果和控制作用各异.在白粉寄生孢的不同菌株中,AQ40、AQ9、AQ117对控制温室黄瓜白粉病具有较好的效果,而AQGA-22、AQ13、AQB15-20对控制苹果白粉病的效果较好.表明这些菌株对黄瓜白粉病和苹果白粉病具有一定的选择性和较好的生防应用潜力.     

三唑酮对禾谷白粉菌菌体形态毒理学的研究

三唑酮杀菌剂对禾谷白粉菌(Erysiphe graminis)分生孢子的萌芽及萌芽后附着胞的发育只有轻微的抑制作用,对次生菌丝和吸器形成有强烈抑制作用。药剂处理已发病盆栽麦苗1天后,粉霉堆上新的分生孢子产生明显减少。两天后则停止产生分生孢子,菌丝顶端开始膨大畸形。4天后菌丝进一步扭曲,形成不规则分枝,老菌丝逐步干瘪,分生孢子萎缩。施药3天后吸器鞘渐从肿胀至衰退。     

凤仙花白粉寄生孢的生物学特性

对凤仙花白粉寄生孢生物学特性研究表明：凤仙花白粉寄生孢生长温度为10～30℃，pH值为5～10；最适生长及产孢温度为20℃，pH值为7。有利于菌落生长的碳、氮源分别为葡萄糖、乳糖和蛋白胨；乳糖和牛肉膏最适于其产孢。光照对菌落生长及孢子产生有明显促进作用。以乳糖作为碳源，牛肉膏作为氮源的察氏培养基有利于孢子的产生。     

白粉菌重寄生菌的分离鉴定及其生防效果初评

从新疆石河子地区3种花卉上采集的150份白粉病株样本中分离出白粉菌重寄生真菌,对代表性菌株进行形态特征观察与ITS-rDNA序列分析：分离物的分生孢子器深棕色,多聚生,大小为（40.66～82.92）μm×（34.65～63.05）μm;分生孢子单胞、无色,两端含油球,大小为（3.88～5.67）μm×（2.19～2.75）μm;菌株的ITS-rDNA序列与Ampelomyces quisqualis序列的同源性达94%～100%,由此将其鉴定为白粉寄生孢（A. quisqualis）。测定该菌对荷兰菊白粉病菌的重寄生效能及控病效果,发现供试的12个菌株均可寄生于荷兰菊白粉病菌上,平均重寄生指数为26.21;菌株As-81和Rh-60对白粉病的防效较好,分别为46.62%和46.15%。     

Comparison of three biological control agents against cucumber powdery mildew (Sphaerotheca fuliginea) in semi-commercial-scale glasshouse trials

The effect of three reported biological control agents, Ampelomyces quisqualis, Verticillium lecanii and Sporothrix flocculosa, was tested against cucumber powdery mildew (Sphaerotheca fuliginea). Two glasshouse experiments, one in the summer and one in winter/spring were conducted on a semi-commercial scale. In both experiments, a susceptible and a partially resistant cultivar were used. In the second experiment, the additional effect of integration of biological control and silicon amendments to the nutrient solution was also assessed. In both experiments, A. quisqualis did not control the disease. V. lecanii had a small effect on powdery mildew in the first experiment but not in the second. S. flocculosa gave the best control of powdery mildew in both experiments. In the first experiment, weekly application of S. flocculosa reduced disease in the partially resistant cultivar to the same level as a treatment in which the fungicides bupirimate and imazalil were each applied once. Addition of silicon in the nutrient solution in a concentration of 0.75 mM reduced disease by 10–16%, averaged over all treatments. There was no interaction between silicon and the biocontrol agents. Yield was recorded in the second experiment and was significantly increased by the fungicide treatment compared to the control in the partially resistant cultivar. Yield in the treatment with S. flocculosa was not significantly different from the fungicide treatment in this cultivar. Silicon had no effect on yield in either cultivar.     

Control of cucumber powdery mildew by the hyperparasite Ampelomyces quisqualis and fungicides

Application of conidial suspensions of the hyperparasite Ampelomyces quisqualis to greenhouse cucumbers inoculated with Sphaerotheca fuliginea increased cucumber yield compared with an untreated control. Similar yield increases were obtained with triforine and also when a reduced rate of triforine and the hyperparasite were combined. A. quisqualis extensively parasitized S. fuliginea and also, in experiments with commercial cucumber crops, Erysiphe cichoracearum.     

寡聚糖诱导黄瓜对白粉病抗病反应的超微结构研究

 中科6号(2%氨基寡糖素)处理黄瓜植株叶片,5 d后接种白粉菌Sphaerotheca fuliginea(Schlecht.) Poll.,可诱导黄瓜Cucumis sativus产生对白粉病的抗病性,寄主细胞对病原菌的侵入产生了防卫反应结构和物质以及过敏性坏死反应。表现为寄主细胞壁加厚,染色加深,寄主细胞壁下产生多层次结构的乳突,在寄主细胞壁与质膜之间有黑色物质沉积;吸器外质膜皱褶,染色加深,吸器外基质中出现染色加深的颗粒状电子沉积物;寄主细胞质紊乱,细胞器解体,整个寄主细胞解体、坏死。     

Biological control mechanisms of D-pinitol against powdery mildew in cucumber

D-pinitol is an effective agent for controlling powdery mildew (Podosphaera xanthii) in cucumber. In this study, we determined the mechanisms of D-pinitol in controlling powdery mildew in cucumber plants. We compared P. xanthii development on cucumber leaf surface treated with D-pinitol or water (2 mg ml⁻¹) at different time points after inoculation. The germinating conidia, hyphae, and conidiophores of the pathogen were severely damaged by D-pinitol at any time of application tested. The highest level of suppression of fungal development was obtained at 3 days after inoculation. The contents of chlorophyll, total phenolics, flavonoid, and gallic acid and its derivatives (GAD); the activities of phenylalanine ammonialyase (PAL), polyphenoloxidase (PPO), peroxidase (POX), and superoxide dismutase (SOD); and the expression of the genes encoding for PR-1, peroxidase (POX), lipoxygenase (LOX1), chitinase (Chit1) were higher in the cucumber leaves treated with D-pinitol and inoculated than in the leaves either treated with D-pinitol or inoculated with the pathogen. These results suggest that D-pinitol triggers several plant defense responses in cucumber leading to pathogen suppression and resistance to powdery mildew.     

Overwintering of Ampelomyces mycoparasites on apple trees and other plants infected with powdery mildews

Apple shoots and aerial parts of 13 other plant species infected with powdery mildews during the previous season were collected in late winter and early spring between 1998 and 2003 at a total of 34 sample sites in Hungary. Samples were examined for the presence of overwintering structures of Ampelomyces, common mycoparasites of powdery mildews. Pycnidia and resting hyphae resembling those of Ampelomyces were found on six plant species, including apple. Their viability and subsequent mycoparasitic activity of the hyphae emerging from the overwintered fungal structures were studied in vitro to determine whether they can serve as sources of primary inocula of Ampelomyces in the spring. Overwintered pycnidia of Ampelomyces collected in the spring, and produced in both the ascomata and the conidiophores of powdery mildews during the previous season, initiated the life cycle of these mycoparasites when placed close to fresh powdery mildew colonies in vitro. Similarly, thick-walled resting hyphae, found in the dried powdery mildew mycelia which covered the overwintered aerial parts of the host plants, also germinated and gave rise to new intracellular pycnidia of Ampelomyces when powdery mildew colonies were inoculated with them in vitro. On apple trees, Ampelomyces mycoparasites overwintered as resting hyphae in the dried powdery mildew mycelia covering the shoots and in the parasitized ascomata of Podosphaera leucotricha on the bark and the scales of the buds. Approximately 31% of the field samples collected from apple trees in spring between 1998 and 2003 contained overwintered structures of Ampelomyces. Artificial bursting of apple buds in the laboratory showed that both P. leucotricha and Ampelomyces start their life cycle during or soon after bud burst, but Ampelomyces can only slowly follow the spread of its mycohost on infected leaves. Most probably, the mycoparasites did not overwinter in the dormant hyphae of P. leucotricha in the buds, but only on the bark and the bud scales, as their hyphae were not found in the young hyphae of apple powdery mildew that appeared on the leaf tissues during bud burst. This study demonstrated that Ampelomyces mycoparasites can survive the winter in the field as pycnidia and as resting hyphae in the dried mycelia of their mycohosts.     

Resistance levels of cucumber to <Emphasis Type="Italic">Podosphaera xanthii</Emphasis> in a growth chamber are related to haustorial formation and hyphal branching frequency

To clarify relationships between powdery mildew resistance of cucumber and hyphal developmental state of the pathogen, haustorial formation and the hyphal branching frequency were compared among cucumber varieties that differ in resistance levels to powdery mildew pathogen Podosphaera xanthii. Cotyledons of four cultivars were inoculated with P. xanthii. By 2 days after inoculation, secondary haustoria had developed from the first hyphal cell that formed beside the conidium in susceptible cultivars. The fungus on susceptible cultivars also tended to have hyphal branches just after the hyphal cell producing haustoria.     

30%氟菌唑可湿性粉剂防治黄瓜白粉病田间药效试验

进行田间试验以明确30%氟菌唑可湿性粉剂防治黄瓜白粉病的效果。结果表明,30%氟菌唑可湿性粉剂能够很好的控制黄瓜白粉病,防治效果明显高于对照,且对作物安全。     

Effect of seventeen fungicolous fungi on sporulation of cucumber powdery mildew

Nineteen isolates of 17 different fungal species thriving upon other fungi were tested for their ability to control sporulation of cucumber powdery mildew,Sphaerotheca fuliginea. More than half of the fungi reduced the number of healthy conidiophores to less than 10%.Tilletiopsis albescens was superior toAmpelomyces quisqualis. Three species, viz.A. quisqualis, Aphanocladium album andT. albescens, were selected for further greenhouse experiments.Samenvatting Negentien isolaten behorend tot 17 verschillende schimmelsoorten werden getoetst op hun bruikbaarheid voor de biologische bestrijding van komkommermeeldauw aan de hand van effecten op sporulatie. Meer dan de helft van de getoetete isolaten reduceerde het aantal gezonde conidioforen tot minder dan 10%. De werking vanTilletiopsis albescens was enigszins beter dan die van de meestal gebruikte hyperparasietAmpelomyces quisqualis. Van de getoetste schimmels werden er drie, n.l.A. quisqualis, Aphanocladium album enT. albescens, geselecteerd voor kasproeven.