Eyespot of Cereals Revisited: ITS phylogeny Reveals New Species Relationships

Four species so far classified in Pseudocercosporella or Ramulispora (hyphomycetes) are associated with eyespot disease symptoms of cereals. Two of these have been linked to teleomorphs that were described in Tapesia. Sequence data derived from the Internal Transcribed Spacer region (ITS1, 5.8S and ITS2) of the rDNA operon showed, however, that the eyespot fungi associated with Tapesia are not congeneric with Ramulispora sorghi, the type of Ramulispora. The genus name Tapesia is now rejected in favour of the conserved name Mollisia, which appears to comprise heterogeneous fungi. Tapesia yallundae is not closely related to the type of Mollisia, M. cinerea, but clusters separately, being more closely allied to species with Cadophora anamorphs. A new holomorph genus, Oculimacula, is therefore proposed for teleomorphs of the eyespot fungi, while the anamorphs are accommodated in Helgardia gen. nov.     

Molecular phylogeny reveals phenotypic evolution of powdery mildews (Erysiphales, Ascomycota)

Powdery mildew fungi, comprising 16 genera and ca. 900 species, are exclusively obligate biotrophs of plants. Although several publications have addressed the phylogeny and evolution of powdery mildews based on morphology and host relationships, this review focuses on the evolution of several phenotypic characters based on molecular phylogeny: (1) morphology of appendages; (2) mycelium, ectoparasitic or endoparasitic; (3) number of asci per chasmothecium (fruiting body of powdery mildews), e.g., one to several; (4) conidiogenesis, conidia catenescent (i.e., maturing in chains: Euoidium-type) or maturing one at a time (Pseudoidium-type). Putative ancestral features of the powdery mildews are described as follows. In teleomorphs, large-sized chasmothecia, containing many 8-spored asci, had many appendages with uncinate-circinate apices, arising around the supraequatorial part of chasmothecia. In anamorphs, conidia were produced in chains (Euoidium-type) without distinct fibrosin bodies. Parasitism was ectoparasitic.     

Molecular variability and phylogenetic relationships among different species and populations of <Emphasis Type="Italic">Pratylenchus</Emphasis> (Nematoda: Pratylenchidae) as inferred from the analysis of the ITS rDNA

Sequence comparisons and molecular phylogenetic analyses were used to describe the nucleotide variability of the ITS containing regions of eighteen Pratylenchus species and several populations. Comparative analysis of nucleotide sequences of the rDNA internal transcribed spacers (ITS1 and ITS2) among Pratylenchus species used in the present study demonstrates that ITS sequences can widely vary in primary sequence and length. Alignment of eighty-seven Pratylenchus sequences and one outgroup taxon reveals the presence of ambiguous regions that have the greatest effect on phylogeny reconstruction. Phylogenetic analyses using Bayesian Inference, Neighbour Joining-LogDet, Maximum Likelihood and Maximum Parsimony, distinguished twelve highly or moderately supported major clades within Pratylenchus. Our results support the taxonomic usefulness of the ITS region to identify root-lesion nematode species of the genus Pratylenchus but the high nucleotide variability, sometimes, can preclude its use to resolve relationships among all members of the genus. In addition, the phylogenetic groupings are not congruent with those defined by characters derived by lip patterns and numbers of lip annuli.     

Oidium neolycopersici: intraspecific variability inferred from amplified fragment length polymorphism analysis and relationship with closely related powdery mildew fungi infecting various plant species

Previous works indicated a considerable variation in the pathogenicity, virulence, and host range of Oidium neolycopersici isolates causing tomato powdery mildew epidemics in many parts of the world. In this study, rDNA internal transcribed spacer (ITS) sequences, and amplified fragment length polymorphism (AFLP) patterns were analyzed in 17 O. neolycopersici samples collected in Europe, North America, and Japan, including those which overcame some of the tomato major resistance genes. The ITS sequences were identical in all 10 samples tested and were also identical to ITS sequences of eight previously studied O. neolycopersici specimens. The AFLP analysis revealed a high genetic diversity in O. neolycopersici and indicated that all 17 samples represented different genotypes. This might suggest the existence of either a yet unrevealed sexual reproduction or other genetic mechanisms that maintain a high genetic variability in O. neolycopersici. No clear correlation was found between the virulence and the AFLP patterns of the O. neolycopersici isolates studied. The relationship between O. neolycopersici and powdery mildew anamorphs infecting Aquilegia vulgaris, Chelidonium majus, Passiflora caerulea, and Sedum alboroseum was also investigated. These anamorphs are morphologically indistinguishable from and phylogenetically closely related to O. neolycopersici. The cross-inoculation tests and the analyses of ITS sequences and AFLP patterns jointly indicated that the powdery mildew anamorphs collected from the above mentioned plant species all represent distinct, but closely related species according to the phylogenetic species recognition. All these species were pathogenic only to their original host plant species, except O. neolycopersici which infected S. alboroseum, tobacco, petunia, and Arabidopsis thaliana, in addition to tomato, in cross-inoculation tests. This is the first genome-wide study that investigates the relationships among powdery mildews that are closely related based on ITS sequences and morphology. The results indicate that morphologically indistinguishable powdery mildews that differed in only one to five single nucleotide positions in their ITS region are to be considered as different taxa with distinct host ranges.     

A Reassessment of the Species Concept in Eutypa lata, the Causal Agent of Eutypa Dieback of Grapevine

ABSTRACT Eutypa dieback is a vascular disease of several cultivated crops and trees worldwide. The attribution of the name to the agent responsible for branch dieback is ambiguous. Pathogenicity of Eutypa sp. first was reported on apricot and the causal agent was named E. armeniacae. However, no morphological differences were reported with the previously described E. lata, and some authors considered both species synonymous. Others regarded them as distinct species on the basis of pathogenesis and molecular analysis. We further investigated the relatedness of both species by phylogenetic analyses of the internal transcribed spacer region and beta-tubulin gene. These analyses included several other taxa placed in the same family (Diatrypaceae), and yielded three groups. The isolates referred to as E. lata in previous work clustered with Diatrype stigma in one group. Isolates of E. armeniacae and E. lata clustered in a second group, supporting the synonymy of these species. The third group included other Eutypa spp. supporting the polyphyletic origin of this genus. Measurements of conidia length and secondary metabolite production of isolates supported the phylogenetic analyses. Secondary metabolites appeared to be a synapomorphic character shared by several taxa including E. lata, E. armeniacae, E. laevata, and E. petrakii var. petrakii.     

Fish-isolated Naegleria strains and their phylogeny inferred from ITS and SSU rDNA sequences

Effort was made to identify Naegleria strains isolated from organs of fish, using phylogenetic analyses of SSU rDNA and ITS sequences. Eighteen fish-isolated strains studied enlarged substantially the so far available set of Naegleria strains characterized by both molecular markers. The phylogenetic analyses of separate and concatenated SSU rDNA and ITS sequences revealed phylogenetic relationships of strains under study; however, they failed to solve classification of fish-isolated strains into species. The sequence similarity of strain-representatives of Naegleria species as well as data obtained on intragenomic variation of ITS sequences discouraged the authors from the definition of new species. The results of the present study provide evidence of a need to re-evaluate the current practice of setting boundaries between species of the genus Naegleria. Sequences obtained in this study have been deposited in GenBank with accession numbers DQ768714-DQ768743.     

A phylogenetic analysis by multilocus enzyme electrophoresis and multiprimer random amplified polymorphic DNA fingerprinting of the Leishmania genome project Friedlin reference strain.

We have assessed the phylogenetic status of the Leishmania genome project Friedlin reference strain by MLEE and multiprimer RAPD including a set of 9 stocks representative of the main Leishmania species and of the whole genetic diversity of the Leishmania genus. To our knowledge, the detailed genetic characterization of the Friedlin strain has never been published before. As previously recorded (Tibayrenc et al. 1993), MLEE and RAPD data gave congruent phylogenetic results. The Friedlin reference strain was definitely attributed to Leishmania (Leishmania) major Yakimoff et Schokhor, 1914. Five specific RAPD patterns made it possible to distinguish between the Friedlin strain and the 2 other L. (L.) major stocks included in the study. Various specific MLEE and RAPD characters permitted to distinguish between the Leishmania species included in the study. All these characters are usable to detect accidental laboratory mix-ups involving the Friedlin reference strain. In confirmation with previous studies involving a more limited set of genetic markers, the general genetic diversity of the Leishmania genus proved to be considerable. It must be made clear that only one strain cannot be considered as representative of the whole genetic variability of the genus Leishmania. In the future, it is therefore advisable to complement the results obtained in the framework of the Leishmania genome project with data from other strains that should be selected on a criterion of important genetic differences with the Friedlin strain.     

现代分子生物学技术在木霉鉴定及多样性分析中的应用

木霉是一类重要的生防真菌,具有很大的农业应用潜力。对分离培养的木霉准确鉴定,对其在农业生产中的应用至关重要。近年来,分子生物学技术在木霉鉴定方面得到了广泛应用,本文综述了rDNA-ITS序列分析、通用引物PCR(UP-PCR)、随机扩增多态性DNA(RAPD)、扩增片段长度多态性(AFLP)等分子技术在木霉鉴定与多样性分析中的应用。     

Green Mold Diseases of Agaricus and Pleurotus spp. Are Caused by Related but Phylogenetically Different Trichoderma Species

ABSTRACT Producers of champignon (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus) are facing recent incidents of green mold epidemics in Hungary. We examined 66 Trichoderma strains isolated from Agaricus compost and Pleurotus substrate samples from three Hungarian mushroom producing companies by a polymerase chain reaction-based diagnostic test for T. aggressivum, sequence analysis of the internal transcribed spacer region 1 (ITS1) and ITS2 and (selectively) of the fourth and fifth intron of translation elongation factor 1alpha (tef1alpha), and restriction fragment length polymorphism of mitochondrial DNA. Seven Trichoderma species were identified: T. aggressivum f. europaeum (17 isolates), T. harzianum (three isolates), T. longibrachiatum (four isolates), T. ghanense (one isolate), T. asperellum (four isolates), T. atroviride (nine isolates), and a still undescribed phylogenetic species, Trichoderma sp. DAOM 175924 (28 isolates). T. aggressivum f. europaeum was exclusively derived from A. bisporus compost, whereas Trichoderma sp. DAOM 175924 exclusively occurred in the substrate for Pleurotus cultivation. Sequences of the latter strains were co-specific with those for Trichoderma pathogens of P. ostreatus in Korea. The widespread occurrence of this new species raises questions as to why infections by it have just only recently been observed. Our data document that (i) green mold disease by T. aggressivum f. europaeum has geographically expanded to Central Europe; (ii) the green mold disease of P. ostreatus in Hungary is due to the same Trichoderma species as in Korea and the worldwide distribution of the new species indicates the possibility of spreading epidemics; and (iii) on mushroom farms, the two species are specialized on their different substrates.     

A new genus of parasitic copepod (Siphonostomatoida: Caligidae) from the razorback scabbardfish, Assurger anzac (Trichiuridae) off New Caledonia

A new genus and species, Avitocaligus assurgericola gen. et sp. n., of the family Caligidae is established based on an ovigerous female collected from a razorback scabbardfish, Assurger anzac (Alexander), caught off New Caledonia. This is the first record of any parasitic copepod from this fish. The new genus is placed in the Caligidae since it possesses the caligid cephalothorax incorporating the first to third pedigerous somites. It also exhibits biramous first and fourth swimming legs but lacks dorsal plates on the fourth pedigerous somite. This combination of characters serves to differentiate the new genus from existing genera. In addition, it possesses loosely coiled, uniseriate egg sacs, concealed between the middle lamellar plates on the genital complex and the ventral plates on the abdomen. Preliminary phylogenetic analysis with a restricted matrix suggests that the new genus represents the earliest offshoot from the main caligid lineage since it does not exhibit the dominant exopod on the fourth swimming leg found in all other members of the Caligidae, including the genus Euryphorus. It strongly supports the newly recognized monophyletic status of the Caligidae, incorporating the genera formerly placed in the Euryphoridae.     

Molecular phylogenetic analysis of <Emphasis Type="Italic">Peronosclerospora</Emphasis> (Oomycetes) reveals cryptic species and genetically distinct species parasitic to maize

Downy mildews are amongst the most widespread and economically important pathogens of cultivated grasses in the tropics and subtropics. Despite their importance, molecular methods, particularly DNA sequence analysis, have rarely been applied to either species identification or to the determination of phylogenetic relationships between species. Here we report the presence of several cryptic species in the genus Peronosclerospora. Further we confirm that maize can be parasitised by several species of Peronosclerospora, including P. eriochloae, which has not been reported previously as a pathogen of maize. The presence of 14 distinct phylogenetic lineages, including three that are parasitic to maize, highlights the current fragmentary knowledge on the diversity and classification of species within Peronosclerospora. Species identification in Peronosclerospora has been traditionally based on the host genus and a set of variable morphological characteristics, which has meant that the identification of species is often unreliable. This situation is primed for the application of molecular techniques for the identification of species. One of the lineages parasitic to maize in Australia has not yet been formally described and its distribution is not known. Future investigation including a broad sampling of downy mildews from maize and other cultivated and native grasses on a world-wide basis is a prerequisite to a re-evaluation of quarantine regulations aimed at restricting or limiting their spread.     

松墨天牛病原菌及其致病性研究

对华东地区松材线虫病疫区和松墨天牛主要发生的13个地区随机抽样调查,共获松墨天牛病原真菌9属12种,病原细菌2属2种。其中,我国首次报道的松墨天牛病原菌新种类有：金龟子绿僵菌小孢变种Metarhizium anisopliae var.anisopliae、粉拟青霉Paecilomyces farinosus、尖镰孢Fusarium oxysporum、蜡蚧轮枝霉Verticillum lecanii、青霉Penicillium spp.、黄曲霉Aspergillus flavus、曲霉Aspergillus spp.、木霉Trichoderma spp.和粘质沙雷氏菌Serratia marcescens。经致病性测定表明,球孢白僵菌、金龟子绿僵菌小孢变种、粉拟青霉对松墨天牛有较强的致病力,处理后16d的致死率分别为100%、100%和70%。     

杆状病毒新的分类地位和书写方式

2020年10月ICTV更新了主要病毒名录，该文件新增了纳尔达病毒纲Naldaviricetes和勒乏病毒目Lefavirales。勒乏病毒目含中有包括杆状病毒科Baculoviridae在内的3个科，而杆状病毒科分为4个属：甲型杆状病毒属Alphabaculovirus、乙型杆状病毒属Betabaculovirus、丙型杆状病毒属Deltabaculovirus和丁型杆状病毒属Gammabaculovirus，该名录中杆状病毒科有85个主要种。根据ICTV网站病毒名称和种名的书写规范，杆状病毒的种名由其宿主昆虫的种名和病毒特性词（如nucleopolyhedrovirus和granulovirus）组成，其中宿主昆虫的属名首字母大写，其余字母均小写。病毒的种名（在用于系统分类时）书写全部用斜体，但其他情形时病毒名称（包括其宿主的属和种名）均采用正体书写。杆状病毒名称的缩写一般采用宿主属名和种名的前两位双字母＋病毒特性词缩写的方式，但16种传统杆状病毒的缩写仍沿用宿主的属名和种名首位单字母＋病毒特性词的缩写的方式。     

东南亚寡鬃实蝇(Triphridae,Dacinae,Dacus)记述

本文整理了东南亚有分布的寡鬃实蝇属实蝇共48种,分属5亚属,包括其中文名称、学名和地理分布,对无中文名称的32种实蝇给予了中文命名,编制该48种实蝇检索表。并对云南边境诱捕获得的2种寡鬃实蝇进行描述和提供特征图。     

The genus Hyalomma Koch, 1844. IV. Redescription of all parasitic stages of H. (Euhyalomma) lusitanicum Koch, 1844 and the adults of H. (E.) franchinii Tonelli Rondelli, 1932 (acari: ixodidae) with a first description of its immature stages

Hyalomnma (Euhyalomma) lusitanicum Koch, 1844 and Hyalomma (Euhyalomma) franchinii Tonelli Rondelli, 1932 are amongst the most poorly studied of those species within the genus Hyalomma Koch, 1844 that are restricted to the Mediterranean region. No comprehensive morphological study has been done to date, and the immature stages of H. (E.) franchinii have not been described. Here all the parasitic stages of H. (E.) lusitanicum and the adults of H. (E.)franchinii are redescribed, and the immature stages of the latter species are described for the first time. Data on hosts, geographic distribution and disease relationships are provided.     

Characterization and taxonomic reassessment of the box blight pathogen Calonectria pseudonaviculata,introducing Calonectria henricotiae sp. nov.

Calonectria pseudonaviculata, the causal agent of the disease of Buxus spp. known as ‘box blight’, was first detected in the mid‐1990s in the UK and New Zealand. Since then, the geographic range of box blight has rapidly expanded to at least 21 countries throughout temperate regions of the world, causing significant losses in nurseries, gardens and wild boxwood populations. This study determined the genetic diversity in a collection of 234 Calonectria isolates from diseased Buxus plants, originating from 15 countries and four continents. Two genetic clades, G1 and G2, were identified within this sample using multilocus phylogenetic analysis. The application of genealogical concordance phylogenetic species recognition criteria using four independent nuclear loci determined that the Calonectria isolates in these two clades are separate phylogenetic species. The isolates in the G1 clade were upheld as C. pseudonaviculata sensu stricto. Based on phylogenetic distinctiveness and the lack of mating, a new species is proposed, Calonectria henricotiae sp. nov., for the Calonectria isolates in the G2 clade. A PCR‐RFLP assay and real‐time PCR assays were developed to easily and reproducibly differentiate these species. To assess the practical implications of the identification of the two species, their physiology, fungicide susceptibility and pathogenicity were compared. No differences in pathogenicity were observed. However, C. henricotiae isolates exhibited greater thermotolerance and reduced sensitivity to specific triazole as well as strobilurin fungicides. The identification of a second phylogenetic species causing box blight may have a substantial impact on the epidemiology and control of this destructive disease.     

书虱及其分子生物学研究进展

书虱（book lice）是目昆虫中有重要经济意义的一个类群,也是世界储粮保护中的常见害虫。本文在概述书虱的危害及其主要种类的基础上,从书虱近似种分子鉴定、分子系统发育、共生菌分子检测与协同进化、种群遗传结构与多态性以及书虱抗性分子机制等几个方面对国内外书虱分子生物学研究现状进行了分析,并就分子生物学技术在书虱领域的进一步研究和应用进行了初步展望。