金银忍冬白粉菌及其重寄生菌的报道

通过对来自中国青岛金银忍冬的调查,发现一中国新记录种——金银忍冬白粉菌(Erysiphe caprifoli-acearum var. caprifoliacearum)并在其上首次发现重寄生菌——白粉寄生孢(Ampelomyces quisqualis)。根据采集的材料对其进行了详细的形态描述和显微拍照。研究标本保存于青岛农业大学真菌标本室(HMQAU)。     

青岛崂山的重寄生菌白粉寄生孢及其寄主多样性

2005－2007年从青岛崂山的16科30属35种植物上采集了143份白粉菌样品,经形态鉴定分属于7属22种。其中40份样品中检测到白粉寄生孢Ampelomyces quisqualis,其寄主植物属于8科14属15种,其寄主真菌属于7属10种白粉菌。统计分析发现,多孢穆氏节丝壳上白粉寄生孢的发生率和重寄生强度均为最高;群落组成分析发现,棕丝单囊壳为白粉寄生孢寄主真菌中的优势种,其重要值为89.22%;菊科为白粉寄生孢寄主植物中的优势科,其重要值为97.85%。     

中国白粉菌的四个新记录分类群

报道了中国白粉菌科Erysiphaceae的四个新记录分类群,即:寄生于大刺儿菜上的梅厄白粉菌日本变种Erysiphemayoriivar.japonica,寄生于铺地委陵菜上的瑟门白粉菌Erysiphethuemenii,寄生于美女樱上的马鞭草高氏白粉菌Golovinomycesverbenae以及寄生于牻牛儿苗和老鹳草属上的老鹳草新白粉菌Neoerysiphegeranii。研究标本保存在赤峰学院菌物标本室(CFSZ)。     

白粉菌属一新种

报道了寄生在人参上的白粉菌属一新种;人参白粉菌,此为白粉菌有性型在五加和植物上寄生的首次记载。模式标本存入在解放军农牧大学真菌标本室。     

浙北几种园林观赏植物白粉菌及其两个新种

本文列出几种浙江省未报道过的园林观赏植物白粉菌,其中包括两个新种,即寄生于云实科紫荆的紫荆白粉菌Erysiphe cercidis T.Xu sp.nov.以及寄生于八角枫科瓜木的八角枫钩丝壳Uncinula alangii T.xu sp.nov.。新种有汉文及拉丁文描述。     

白粉菌属一新种

本文报道了寄生在白花菜科醉蝶花属上的一个白粉菌属新种醉蝶花白粉菌Erysiphecleomes白花菜科是白粉菌在我国的寄主科新记录。新种有中文和拉丁文描述。     

白粉菌属一新种——南非金钟花白粉菌

寄生于南非金钟花（PhygeliuscapensisE.May）上的白粉菌属新种:南非金钟花白粉菌ErysiphephygeliiWangetZhangsp.nov.。模式标本分别保存于云南农业大学植病所真菌标本室（MHYAU）和中科院微生物所真菌标本室（HMAS）。     

武夷山白粉菌新种

本文描述了武夷山白粉菌的3个新分类单位。它们是寄生于大戟科连氏野桐上的新种野桐白粉菌(Erysiphe malloti sp.nov.),忍冬科白马桑上的新种锦带花白粉菌(Erysipheweigelae sp.nov.),以及绣球科圆锥绣球上的新种绣球钩丝壳(Uncinula hydrangeae sp.nov.)。绣球科是钩丝壳属真菌寄主科的世界新纪录。新种均有汉文和拉丁文描述以及建立新种的讨论。     

白粉菌属一新种──南非金钟花白粉菌

寄生于南非金钟花（PhygeliuscapensisE.May）上的白粉菌属新种:南非金钟花白粉菌ErysiphephygeliiWangetZhangsp.nov.。模式标本分别保存于云南农业大学植病所真菌标本室（MHYAU）和中科院微生物所真菌标本室（HMAS）。     

内蒙古白粉菌4个新记录种

报道了内蒙古白粉菌4个新记录种,分别是寄生在白桦Betula platyphylla上的桦木白粉菌Erysiphe betulina、大果榆Ulmus macrocarpa上的榆白粉菌原变种Erysiphe ulmi var.ulmi、刺果茶藨Ribes burejense上的醋栗单囊白粉菌Podosphaera mors-uvae和栾树Koelreuteria paniculata上的栾树叉钩丝壳Sawadaea koelreuteriae。其中,白桦Betula platyphylla和刺果茶藨子Ribes burejense为上述白粉菌的国内新记录寄主,文中提供了详细的形态描述和线条图。引证标本保存在赤峰学院菌物标本室(CFSZ)。     

Genetic variability and mycohost association of Ampelomyces quisqualis isolates inferred from phylogenetic analyses of ITS rDNA and actin gene sequences

Ampelomyces quisqualis complex is well known as the most common and widespread hyperparasite of the family Erysiphaceae, the cause of powdery mildew diseases. As commercial biopesticide products it is widely used to control the disease in field and plastic houses. Although genetic diversity within Ampelomyces isolates has been previously recognized, a single name A. quisqualis is still applied to all pycnidial intracellular hyperparasites of powdery mildew fungi. In this study, the phylogenetic relationships among Ampelomyces isolates originating from various powdery mildew fungi in Korea were inferred from Bayesian and maximum parsimony analyses of the sequences of ITS rDNA region and actin gene. In the phylogenetic trees, the Ampelomyces isolates could be divided into four distinct groups with high sequence divergences in both regions. The largest group, Clade 1, mostly accommodated Ampelomyces isolates originating from the mycohost Podosphaera spp. (sect. Sphaerotheca). Clade 2 comprised isolates from several genera of powdery mildews, Golovinomyces, Erysiphe (sect. Erysiphe), Arthrocladiella, and Phyllactinia, and was further divided into two subclades. An isolate obtained from Podosphaera (sect. Sphaerotheca) pannosa was clustered into Clade 3, with those from powdery mildews infecting rosaceous hosts. The mycohosts of Ampelomyces isolates in Clade 4 mostly consisted of species of Erysiphe (sect. Erysiphe, sect. Microsphaera, and sect. Uncinula). The present phylogenetic study demonstrates that Ampelomyces hyperparasite is indeed an assemblage of several distinct lineages rather than a sole species. Although the correlation between Ampelomyces isolates and their mycohosts is not obviously clear, the isolates show not only some degree of host specialization but also adaptation to their mycohosts during the evolution of the hyperparasite.     

A hyperparasite affects the population dynamics of a wild plant pathogen

Assessing the impact of natural enemies of plant and animal pathogens on their host's population dynamics is needed to determine the role of hyperparasites in affecting disease dynamics, and their potential for use in efficient control strategies of pathogens. Here, we focus on the long‐term study describing metapopulation dynamics of an obligate pathogen, the powdery mildew (Podosphaera plantaginis) naturally infecting its wild host plant (Plantago lanceolata) in the fragmented landscape of the Åland archipelago (southwest Finland). Regionally, the pathogen persists through a balance of extinctions and colonizations, yet factors affecting extinction rates remain poorly understood. Mycoparasites of the genus Ampelomyces appear as good candidates for testing the role of a hyperparasite, i.e. a parasite of other parasites, in the regulation of their fungal hosts' population dynamics. For this purpose, we first designed a quantitative PCR assay for detection of Ampelomyces spp. in field‐collected samples. This newly developed molecular test was then applied to a large‐scale sampling within the Åland archipelago, revealing that Ampelomyces is a widespread hyperparasite in this system, with high variability in prevalence among populations. We found that the hyperparasite was more common on leaves where multiple powdery mildew strains coexist, a pattern that may be attributed to differential exposure. Moreover, the prevalence of Ampelomyces at the plant level negatively affected the overwinter survival of its fungal host. We conclude that this hyperparasite may likely impact on its host population dynamics and argue for increased focus on the role of hyperparasites in disease dynamics.     

Potential for using Lecanicillium lecanii for suppression of strawberry powdery mildew

Augmenting native populations of the hyperparasite Lecanicillium lecanii suppressed powdery mildew of strawberry, caused by Sphaerotheca macularis f. sp. fragariae in California field trials. Repeated sprays significantly reduced disease compared to the untreated controls for periods of the fruit production season, suggesting possible use as a partial, but not total disease control strategy.     

Extracellular Enzymes and Nutritional Physiology of Ampelomyces quisqualis Ces., Hyperparasite of Powdery Mildew, in vitro

In vitro, the powdery’ mildew hyperparasite Ampelomyces quisqualis produced constitutively two groups of extracellular enzymes; β-glucosidase, β-N-acetylglucosaminidase and acid phosphatase possessing unusual high molecular weights (M, about 340 000), and ribonuclease, β-l→3-glucanase and α-l→4-glucanase representing smaller molecules (M, about 15 000–55 000). As can be concluded from adsorption to Concanavalin A-Sepharose 4 B, these enzymes are of glycoprotein nature Furthermore, traces of phospholipase could be detected in all of the isolates tested, whereas only phosphorylated carbohydrate components and nucleotides including cAMP as nutrients. The results of these studies suggest that in the biotrophic phase of parasitization A. qwsqualis interferes with energy metabolism, protein synthesis, cell wall synthesis and, possibly, regulation of the host, whereas proteins and membranes remain nearly unaffected. Thus, depletion of the energy reserves of the powdery mildew may be mainly responsible for the degeneration of host ultrastructure which represents the beginning of the necrotrophic phase of parasitization.     

Constraints to the development of biofungicides: The example of “AQ10”, a new product for controlling powdery mildews

Over recent years, the company ECOGEN Inc. has been successfully developing a biofungicide known under the trade name ‘AQ10’ in the USA where it has been authorized in 1994 for controlling powdery mildews on various host plants. This new product is based on the use ofAmpelomyces quisqualis, an hyperparasitic fungal species infesting representatives ofErysiphaceae (powdery mildews) only. The production process now allows for the hyperparasite to be mass-cultured and formulated into an easily water-dispersed, dry powder which preserves spore viability at room temperature for a period in excess of 12 months. Upon spraying, the conidia germinate rapidly to effectively attack any developing powdery mildew colonies. Efforts are now concentrating on experimental application schedules in vineyards aimed at defining an optimal positioning of the biofungicide within existing disease control programmes. The pilot trials are being conducted over a large number of wine-producing areas under a Mediterranean climate around the world where powdery mildew represents the major pest problem. Results obtained so far show that in order to achieve an optimal, cost-effective, consistent disease control, the biofungicide has to be applied before the incidence of powdery mildew has reached high levels, and at any of the three most susceptible growth stages of grapevine,i.e. bud break, between flowering and bunch closure, and just before veraison. The biofungicide may therefore be used as a curative to slightly preventative control agent likely to fit into any IPM strategies. The various technical problems associated with the development and industrial production of this new biofungicide are largely solved. Constraints relating to designing comprehensive, user-friendly IPM programmes which include ‘AQ10’ still require adjustments in terms of defining spraying dates and intervals according to a range of agricultural practices, climatic changes likely to occur during the season, and compatibility for tank-mixing with other pesticides. A number of additional constraints relate to official registration in various countries, distributors’ and farmers’ acceptance of a new, ‘living’ product: these are still more difficult to address because they claim for a profound change in the users’ general attitude towards controlling diseases of cultivated plants.     

荒漠固沙植物河西菊的白粉病菌

2009–2011年间,在对新疆塔里木盆地进行白粉菌物种多样性调查时,发现荒漠固沙植物河西菊Hexinia polydichotoma白粉病大发生,导致植株大面积死亡。通过对病原菌形态学特征观察和rDNA-ITS序列分析,证明引发新疆塔里木盆地河西菊白粉病大发生的病原菌为野莴苣内丝白粉菌Leveillula lactucae-serriolae,为中国新记录种,河西菊为新寄主。     

Genetic characterization of five powdery mildew disease resistance loci in Arabidopsis thaliana

This paper reports on six Arabidopsis accessions that show resistance to a wild isolate of the powdery mildew pathogen, Erysiphe cichoracearum . Resistance at 7 days post-inoculation in these accessions was characterized by limited fungal growth and sporadic development of chlorotic or necrotic lesions at inoculation sites. Three accessions, Wa-1, Kas-1 and SI-0, were highly resistant, while the other accessions permitted some fungal growth and conidiation. Papilla formation was a frequent host response; however, cell death appeared to be neither a rapid nor a common response to infection. To determine the genetic basis of resistance, segregation analyses of progeny from crosses between each of the resistant accessions and Columbia ( gl1 ), which is susceptible to the powdery mildew pathogen, were performed. For all accessions except SI-0, resistance was conferred by a single locus. SI-0 was unique in that two unlinked loci controlled the disease reaction phenotype. In accessions Wa-1, Kas-1, Stw-0 and Su-0, powdery mildew resistance was encoded by a semi-dominant allele. However, susceptibility was dominant to resistance in accessions Te-0 and SI-0. Mapping studies revealed that powdery mildew resistances in Kas-1, Wa-1, Te-0, Su-0 and Stw-0 were controlled by five independent loci. This study suggests that the Arabidopsis powdery mildew disease will be a suitable model system in which to investigate powdery mildew diseases.     

小麦白粉病抗性基因的导入及AFLP分析

本研究以簇毛麦为抗源,采用杂交与辐射、组织培养相结合的方法,将簇毛麦的抗白粉病基因导入小麦,选育出高产、抗白粉病的小麦新品种和农艺性状较好、抗白粉病的小麦新种质。经AFLP分析,确定4个抗白粉病种质均为含有一段簇毛麦DNA的易位系。并得到3个可能与抗性基因紧密连锁的标记。     

Characterisation of powdery mildew resistance in a segregating diploid rose population

Powdery mildew (Podosphaera pannoso) is one of the most serious fungal diseases on both greenhouse and field grown roses. Improvement of disease resistance is a major selection aim for garden rose breeders. For rose cultivars, being mostly tetraptoid, it is complicated to develop molecular markers for resistance. Hence, a segregating diploid population was established from a cross between 'Yesterday', a commercial available rose variety susceptible to powdery mildew, and R. wichurana, a rose species with resistance to certain isolates of powdery mildew. A progeny of 94 seedlings was planted in the field. The segregation of powdery mildew resistance was studied in this population by means of a bioassay with two different monoconidial isolates of powdery mildew. Based on the response to these inoculations different groups were selected: a first group of genotypes was susceptible to both isolates, other groups were susceptible to one of both isolates and a last group was resistant to both tested isolates. The disease resistance inherits for both isolates in a quantitative way. A genetic map based on AFLP and SSR markers was established and will be used for QTL analysis of powdery mildew resistance.     

抗白粉病小偃麦异代换系的细胞学和RAPD鉴定

利用细胞学和RAPD方法,对从长穗偃麦草与普通小麦复合杂交后代中选育的抗白粉病小麦种质系山农87074－526和山农87074－551进行了鉴定。结果表明,两种质系的根尖细胞染色体数目均为2n=42,花粉母细胞减数分裂中期I（PMC MI）染色体构型为2n=21Ⅱ;二者杂交F1 PMC MI染色体构型亦为2n=21Ⅱ,两种质系分别与小麦中国春的杂种F1 PMC MI染色体构型均为2n=20Ⅱ 2I,说明两种质系为相同的双体异代系。在苗期和成株期两种质系对白粉病15号菌种均表现免疫,其白粉病抗性为显性,并且来自长穗偃麦草,抗白粉病基因位于它们所含的偃麦草染色体上。从80个随机引物中,筛选出2个引物OPE13和OPH15能在两种质系中稳定地扩增出长穗偃麦草亲本的特异DNA片段。