Taxonomic rearrangement of the genus Ulkenia sensu lato based on morphology, chemotaxonomical characteristics, and 18S rRNA gene phylogeny (Thraustochytriaceae, Labyrinthulomycetes): emendation for Ulkenia and erection of Botryochytrium, Parietichytrium, and Sicyoidochytrium gen. nov.

The genus Ulkenia is characterized by the naked protoplast stage within its life cycle. However, the 18S rRNA gene tree clearly shows that this genus is not a natural taxon, because our own isolates and reported strains separately form four well-supported monophyletic groups. These four groups are clearly distinguishable by their profiles of polyunsaturated fatty acids and carotenoid pigments and cell and colony morphology, e.g., persistence of sporangial wall, manner of the cell cleavage at the zoospore formation, and development of the ectoplasmic nets. Therefore, the four groups are assigned to four genera including three new genera, i.e., Ulkenia sensu stricto, Botryochytrium, Parietichytrium, and Sicyoidochytrium gen. nov.     

Revision of the genus Absidia (Mucorales, Zygomycetes) based on physiological, phylogenetic, and morphological characters; thermotolerant Absidia spp. form a coherent group, Mycocladiaceae fam. nov.

The genus Absidia comprises ubiquitously distributed soil fungi inhabiting different growth temperature optima ranging from 20–42 °C. Some of the mesophilic species are important biotechnologically in the biotransformation of steroids or as producers of rennin-like components, whereas species with higher growth temperature optima are of clinical relevance as opportunistic human pathogens. The aim of this study was to investigate the phylogenetic relationships between these species and to establish a revision of their systematics. For this purpose single and combined genealogies based on distance, MP, ML, and Bayesian analyses of aligned nucleotide sequences of the nuclear-encoded genes for actin (act) and for the 5.8S ribosomal RNA flanked by the ITS regions 1 and 2 (comprising 807 and 828 characters, respectively) of 16 Absidia species were reconstructed. The phylogenetic reconstructions suggest a trichotomy of the Absidia genus consisting of a mesophilic, a fast-growing thermotolerant, and a slowly-growing mycoparasitic Absidia group. The trichotomous phylogenetic grouping is concordant with the morphology of the zygospores, which are zygotes resulting from sexual conjugation between two compatible mating partners. Whereas the mesophilic group comprises the majority of absidiaceaeous species forming sterile hair-like, mycelial appendages on the suspensors of their zygospores, the thermotolerant group is characterised by the formation of smooth-walled zygospores, and the mycoparasitic group, namely Absidia parricida and A. zychae, by Mucor-like rough-walled zygospores. Based on the phylogenetic coherence of mesophilic and thermotolerant Absidia species, we propose that the two groups are separated into two distinct genera, Absidia for the mesophilic Absidia species resembling the Absidiaceae and Mycocladus for the thermotolerant species A. corymbifera, A. blakesleeana and A. hyalospora. Because Mycocladus is physiologically, phylogenetically, and morphologically distinct from the Absidiaceae s. str. we suggest that they are classified as a separate family, Mycocladiaceae fam. nov., which comprises the three species M. corymbifer, M. blakesleeanus and M. hyalospora.     

New fungal genera, Tectonidula gen. nov. for Calosphaeria-like fungi with holoblastic-denticulate conidiogenesis and Natantiella gen. nov. for three species segregated from Ceratostomella

Two morphologically similar groups of ascomycetes with globose to subglobose perithecia, elongate necks, unitunicate asci floating freely at maturity, and hyaline ascospores currently placed in Calosphaeria s. lat. and Ceratostomella s. lat., respectively, are studied. The Calosphaeria-like fungi have groups of perithecia growing between cortex and wood, arranged in circular groups with converging necks and piercing the cortex in a common point; the asci with a shallow apical ring and U- to horseshoe-shaped hyaline ascospores are compared with Calosphaeria pulchella, the type species of the genus. Conidiogenesis of the investigated Calosphaeria-like fungi is holoblastic-denticulate; ramichloridium-like and sporothrix-like conidiophores and conidia were formed in vitro. Ascospore and ascus morphology, structure of the ascal apex, ascogenous system, mode of conidiogenesis and the large subunit rRNA sequences of this group differ considerably from C. pulchella and both groups are unrelated. Thus a new genus, Tectonidula, is described with two accepted species, T. hippocrepida and T. fagi; they are separated by ascospore and ascus morphology and holoblastic-denticulate conidiogenesis from the core species of Calosphaeria. The placement of Tectonidula among perithecial ascomycetes is discussed. The relationship of Tectonidula with Barbatosphaeria and two ramichloridium-like hyphomycetous genera Rhodoveronaea and Myrmecridium is investigated. Three species formerly attributed to Ceratostomella are studied. The revision of the herbarium type specimen and fresh material of Ceratostomella ligneola revealed that it is conspecific with Ceratostomella ampullasca and Ceratostomella similis. The LSU phylogeny clearly separated C. ligneola from Ceratostomella s. str. and morphologically similar Lentomitella. On the basis of molecular sequence data and detailed comparison of morphology of asci, ascospores and ascogenous system the genus Natantiella is described for C. ligneola with C. ampullasca and C. similis as its synonyms. Natantiella produced sterile mycelium in vitro.     

Rhodopechys obsoleta (desert finch): a pale ancestor of greenfinches ( Carduelis spp.) according to molecular phylogeny

The evolutionary history of three out of four birds traditionally classified into the genus Rhodopechys birds has been studied by comparing their mitochondrial cytochrome b DNA sequence with that of greenfinches and other genus Carduelis finches. The desert finch (Rhodopechys obsoleta) or a sister extinct species seems to have existed about 6 million years ago in Asian and perhaps African desert-like areas. This bird has no molecular relationship with other Rhodopechys birds and seems to have given rise to the greenfinches radiation, probably by allopatry of marginal or isolated groups; the latter would have evolved to green plumage colours and more simple song modulations (i.e., greenfinches). The possible role of assortative mating and the newly postulated acquired phenotypic characters in greenfinches speciation are discussed.     

Molecular phylogeny and evolution of the genus Neoerysiphe (Erysiphaceae, Ascomycota)

The genus Neoerysiphe belongs to the tribe Golovinomyceteae of the Erysiphaceae together with the genera Arthrocladiella and Golovinomyces. This is a relatively small genus, comprising only six species, and having ca 300 species from six plant families as hosts. To investigate the molecular phylogeny and evolution of the genus, we determined the nucleotide sequences of the rDNA ITS regions and the divergent domains D1 and D2 of the 28S rDNA. The 30 ITS sequences from Neoerysiphe are divided into three monophyletic groups that are represented by their host families. Groups 1 and 3 consist of N. galeopsidis from Lamiaceae and N. galii from Rubiaceae, respectively, and the genetic diversity within each group is extremely low. Group 2 is represented by N. cumminsiana from Asteraceae. This group also includes Oidium baccharidis, O. maquii, and Oidium spp. from Galinsoga (Asteraceae) and Aloysia (Verbenaceae), and is further divided into four subgroups. N. galeopsidis is distributed worldwide, but is especially common in western Eurasia from Central Asia to Europe. N. galii is also common in western Eurasia. In contrast, the specimens of group 2 were all collected in the New World, except for one specimen that was collected in Japan; this may indicate a close relationship of group 2 with the New World. Molecular clock calibration demonstrated that Neoerysiphe split from other genera of the Erysiphaceae ca 35–45 M years ago (Mya), and that the three groups of Neoerysiphe diverged between 10 and 15 Mya, in the Miocene. Aloysia citriodora is a new host for the Erysiphaceae and the fungus on this plant is described as O. aloysiae sp. nov.     

瑞香属和荛花属的数量分类研究

瑞香属和荛花属为瑞香科瑞香亚科的落叶或常绿灌木,中国西南部是瑞香属和荛花属的重要分化中心。全世界共有瑞香属95种、荛花属70种,中国分布有瑞香属52种、荛花属49种。瑞香属和荛花属的分类学研究一直存在不同程度的分歧。花盘形状和果实类型在传统分类中一直是区分瑞香属和荛花属的典型特征,而花盘形态和果实类型在2个属中存在交叉和过渡,部分植物分类学家根据这些特征将两个属进行过不同程度的归并。该研究采用数量分类法对瑞香属77种(变种)和荛花属62种(变种)植物,选取32个形态学性状进行聚类分析和主成分分析。结果表明:聚类分析和主成分分析均显示两属均未形成单系类群。在主成分分析中,前3个主成分分析的贡献值为35.56%,传统分类中用来区分两属的花盘形状、叶序及果实类型等特征对前3个主成分贡献相对较小,因此,传统分类学中对这两个属进行区分的性状并没有典型的分类学意义。同时,聚类图和主成分分析得到的散点图均不能将这两个属区分开来。数量分类研究结果显示两属植物存在明显的交叉,支持瑞香属和荛花属不是两个独立自然类群的观点。     

梭菌属分类研究进展:现状和展望

目前构成梭菌属的微生物在系统发育和表型特征上不一致。多相分类数据表明,梭菌属物种之间差异大。大量基于16S rRNA 基因的系统发育研究表明,梭菌属应被限定为梭菌属类群I,作为狭义梭菌属(Clostridium sensu stricto)。尽管有这方面认识,梭菌属新物种仍持续增加,这些新物种并不能与梭菌属类群I 和标准种丁酸梭菌(C. butryicum)形成一致分支,引发梭菌属分类上的混乱。本文明确了梭菌属物种的范围,即只包括模式种和梭菌属类群I。此外,4 个物种念珠状真杆菌(Eubacterium moniliforme)、旋舞真杆菌(Eubacterium tarantellae)、最大八叠球菌(Sarcina maxima)和胃八叠球菌(Sarcina ventriculi)应被调至梭菌属,分别命名为念珠状梭菌(Clostridium moniliforme)、旋舞梭菌(Clostridium tarantellae)、最大梭菌(Clostridium maximum)和胃梭菌(Clostridium ventriculi)。一个新属哈撒韦氏菌属(Hathewaya)被提议成立,3 个梭菌属物种溶组织梭菌(Clostridium histolyticum)、泥渣梭菌(Clostridium limosum)和解朊梭菌(Clostridiumproteolyticum)重新归为溶组织哈撒韦氏菌(Hathewaya histolytica)、泥渣哈撒韦氏菌(Hathewaya limosa)和解朊哈撒韦氏菌(Hathewaya proteolytica),其中Hathewaya histolytica 为模式种。     

Arthromyces and Blastosporella, two new genera of conidia-producing lyophylloid agarics (Agaricales, Basidiomycota) from the neotropics

Two new genera encompassing three new species of lyophylloid agarics that produce conidia on the basidiomata are described. Arthromyces is a genus comprised of two very different arthrospore-producing mushroom species found in the Greater Antilles and Central America. Blastosporella is a monotypic genus with spherical balls of blastospores covering the pileus surface with age and is known from Hispaniola and Colombia. A key to the species of Arthromyces is included.     

Three new species of Lentinus from northern Thailand

There have been few studies on the taxonomy and biodiversity of the genus Lentinus in Thailand, which is a genus of edible mushrooms. Recently, collections from 17 sites in northern Thailand yielded 47 specimens of Lentinus sensu lato. Three were shown to be new species of Lentinus sensu stricto and Lentinus roseus, L. concentricus and L. megacystidiatus are introduced in this paper. The new species are described and illustrated with line drawings and are justified and compared with similar taxa. Furthermore, ITS sequence data do not match closely with any species presently lodged in GenBank.     

《广西植物志》秋海棠属(Begonia L.)增订

秋海棠属(Begonia L.)隶属于葫芦目(Cucurbitales)秋海棠科(Begoniaceae),有1 800余种,是世界第六大属,主要分布于美洲、非洲和亚洲的热带和亚热带地区,具有极高的观赏价值,亦可作为药用、食用、饮料和饲料等。我国有秋海棠属植物近300种,主要分布于我国的云南和广西等长江以南地区,其中云南有秋海棠属植物100余种。近年来,随着广西地区秋海棠属植物野外调查的不断深入,陆续发现并发表了大量秋海棠属新类群,使得广西产秋海棠属植物数目已超出1991年《广西植物志》(第一卷)收录的19种,因此亟需对发表于不同期刊中的类群进行系统地整理和汇总。鉴于此,该文通过查阅文献资料和考证标本信息,整理并汇总了广西产秋海棠属植物共84种,包括2个变种、11个亚种和46个特有种,新增的65种为《广西植物志》(第一卷)中未收录的类群,并补充了这些类群的特征集要、凭证标本信息和属下分组概况,为今后开展秋海棠属植物的分类修订以及系统学、进化生物学和保护生物学等研究提供了参考依据。     

Cylindrocarpon pauciseptatum sp. nov., with notes on Cylindrocarpon species with wide, predominantly 3-septate macroconidia

A Cylindrocarpon species with up to 10 μm wide, straight and predominantly 3-septate macroconidia, subglobose to ovoidal microconidia and chlamydospores, is described as Cyl. pauciseptatum. It is most similar to Cyl. austrodestructans but no chlamydospores and microconidia are formed in the latter. Similar macroconidia also occur in Cyl. theobromicola, which forms oval to ellipsoidal microconidia at least sparsely and has slightly curved macroconidia, and Cyl. destructans var. crassum, which forms abundant 1-celled microconidia. DNA sequence data of the internal transcribed spacer regions 1 and 2 plus the 5.8S rDNA and the partial beta-tubulin gene were used for phylogenetic inferences. Cylindrocarpon pauciseptatum and Cyl. macrodidymum are monophyletic and are closely related to other species of Cylindrocarpon sensu stricto including members of the Cyl. destructans (teleomorph, Neonectria radicicola) species complex, which accommodates Cyl. liriodendri (teleomorph, Neon. liriodendri), Cyl. destructans var. crassum and Cyl. austrodestructans (teleomorph, Neonectria austroradicicola comb. nov.). Cylindrocarpon theobromicola is distantly related to species of Cylindrocarpon sensu stricto or Neonectria sensu stricto. It clustered among cylindrocarpon-like species with curved macroconidia, of which some belong to the Neon. mammoidea group. Relatively voluminous cells in sporodochial conidiophores of Cyl. theobromicola resembled those described for Campylocarpon, which is closely related to members of the Neon. mammoidea group including Cyl. theobromicola. Cylindrocarpon pauciseptatum has been isolated from roots of Vitis spp. in South-eastern Europe (Slovenia) as well as New Zealand, where it also occurs on roots of Erica melanthera.     

The type species of Apiognomonia, A. veneta, with its Discula anamorph is distinct from A. errabunda

Species of Apiognomonia with their Discula anamorphic states in the Gnomoniaceae, Diaporthales, are known throughout the temperate Northern Hemisphere and cause diseases such as sycamore or plane tree anthracnose. The genus Apiognomonia was described based on A. veneta as the type species; however, there has been disagreement about whether or not A. veneta is a synonym of A. errabunda. Using morphological, ecological, and DNA sequence data we conclude that A. errabunda and A. veneta are different species, although very closely related; thus, A. veneta is the correct name for the type species of Apiognomonia. This conclusion is based on a combined analysis of sequences from the ITS regions of nuclear rDNA for 51 isolates from host plants of eight genera and intron regions from actin, calmodulin and translation elongation factor 1-alpha for over 25 isolates. The type species of the genus Discula is D. nervisequa, the earliest available epithet for D. platani, the lectotype of Discula. D. nervisequa is the anamorph of A. veneta. Based on an examination of the type specimen, we determined that the commonly used name for the anamorph of A. errabunda, D. umbrinella, refers to another species. A. veneta and A. errabunda including their anamorphs are described and illustrated. An account of all synonyms and excluded synonyms is presented.     

Strategies of attack and defense in plant–oomycete interactions, accentuated for Phytophthora parasitica Dastur (syn. P. Nicotianae Breda de Haan)

Oomycetes from the genus Phytophthora are fungus-like plant pathogens that are devastating for agriculture and natural ecosystems. Due to their particular physiological characteristics, no efficient treatments against diseases caused by these microorganisms are presently available. To develop such treatments, it appears essential to dissect the molecular mechanisms that determine the interaction between Phytophthora species and host plants. Available data are scarce, and genomic approaches were mainly developed for the two species, Phytophthora infestans and Phytophthora sojae. However, these two species are exceptions from, rather than representative species for, the genus. P. infestans is a foliar pathogen, and P. sojae infects a narrow range of host plants, while the majority of Phytophthora species are quite unselective, root-infecting pathogens. To represent this majority, Phytophthora parasitica emerges as a model for the genus, and genomic resources for analyzing its interaction with plants are developing. The aim of this review is to assemble current knowledge on cytological and molecular processes that are underlying plant–pathogen interactions involving Phytophthora species and in particular P. parasitica, and to place them into the context of a hypothetical scheme of co-evolution between the pathogen and the host.     

A phenetic study of Cassia sensu lato (Leguminosae-Caesalpinioideae: Cassieae: Cassiinae) in Thailand

Cassia L. sensu lato, a large heterogeneous genus of flowering plants, occurs naturally in the tropics around the world. Recent works based on floral morphology have supported a division of this genus into three genera, namely Cassia L. s. str., Chamaecrista Moench and Senna Mill. In order to investigate this new classification, 508 specimens of 18 taxa of the genus Cassia s.l. grown in Thailand were analyzed using cluster analysis and canonical discriminant analysis. The total 32 vegetative and reproductive morphological characters were employed in these analyses. In cluster analysis, Cassia s.l. can be separated into four groups, respectively viz. Chamaecrista, Senna alata, Senna and Cassia s /str. The four-cluster grouping is discussed. From a canonical discriminant analysis using the four-cluster grouping as a priori groups, it can be concluded that Cassia s. str., Senna, and Chamaecrista are indeed distinct taxa. The three most important characters that separate the three genera are filament length, fruit length, and ovary stalk length. These quantitative characters, together with some qualitative characters, were useful in constructing an identification key to these genera. Among the three genera, it was also found that Senna is rather a heterogeneous taxon. The difference between the studied species was discussed.     

烟杆藓属及烟杆藓在中国的新记录

从形态学而论,烟杆藓属(Buxbaumia Hedw.)在苔藓植物中是一个独特的类型。该文简要介绍了烟杆藓属的历史和该属在中国的研究状况,以及该属的模式种烟杆藓首次在中国的发现。对烟杆藓在新疆的着生生境及群落状况做了详细介绍, 还就扫描电子显微镜观察烟杆藓的孢蒴、蒴齿和孢子形态、中国烟杆藓属分种检索表及属的系统关系进行观察和探讨。     

Comprehensive molecular phylogenetic analysis and evolution of the genus Phyllactinia (Ascomycota: Erysiphales) and its allied genera

Phyllactinia is a unique genus within the Erysiphales (Ascomycota) having a partly endo-parasitic nature of the mycelium within the host plant tissues. We constructed phylogenetic trees for the genus Phyllactinia and its allied genera based on a total of 120 nucleotide sequences of the 28S rDNA and ITS regions to discuss their phylogenetic relationships with special references to host plants, biogeography, evolutionary dating, and taxonomy. The analysis of the Erysiphales confirmed the monophyly of the endo-parasitic genera, i.e. Leveillula, Phyllactinia, and Pleochaeta. Phyllactinia specimens used in this study were divided into six distinctive groups and three subgroups. Interestingly, Leveillula, an obligately endo-parasitic genus of the Erysiphales, grouped together with Phyllactinia, although this was not significantly supported by the Kishino–Hasegawa and Shimodaira–Hasegawa tests. This suggests that the evolution within this group of fungi occurred from partial endo-parasitism to obligate endo-parasitism. The host range of Phyllactinia is mostly confined to woody plants, especially deciduous trees. Betulaceae, Fagaceae, Ulmaceae, Moraceae, and Rosaceae may have close connections to the divergence of the groups and subgroups of Phyllactinia concerned. Most of these plant families are known as major members of the boreotropical flora of the Tertiary, which suggests an early Tertiary origin of this genus. A comparison of the phylogenies of hosts and parasites revealed that host range expansion at higher taxonomic levels (higher than family level) is independent of the phylogeny of plants. Conversely, host range expansions in lower taxonomic levels (infrafamilial or infrageneric) tend to occur within a single family or genus. An estimation of the evolutionary timing using a molecular clock approach suggested that Phyllactinia split from Pleochaeta about 60 M years ago (Ma) in the early Tertiary and divergence of the six major clades of Phyllactinia occurred between 5 and 40 Ma during the Oligocene and Miocene. Divergence within the major clades and within Leveillula occurred maybe from more than 5 Ma onwards during the Pliocene and Quaternary. This is the first comprehensive phylogenetic study of Phyllactinia and other endo-parasitic genera of the Erysiphales.