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1.
Recently, molecular and ultrastructural analyses have resulted in revised phylogenetic hypotheses in the phylum Chytridiomycota. The order Chytridiales, once considered monophyletic, has been subdivided into several new orders. However, the most recent analyses indicate that the emended Chytridiales is also polyphyletic. One monophyletic lineage in Chytridiales includes Cladochytrium, Nowakowskiella, and five other genera. Many of the chytrids in this clade have often been observed growing on decaying plant tissue and other cellulosic substrates from aquatic habitats and moist soils. In this study we analysed combined nu-rRNA gene sequences (partial SSU and LSU) of 30 isolates from North American aquatic and soil samples. Based on molecular monophyly and zoospore ultrastructure, we designate this clade as a new order, Cladochytriales, which includes four families: Cladochytriaceae, Nowakowskiellaceae, Septochytriaceae fam. nov., and Endochytriaceae.  相似文献   

2.
Based on molecular studies using 1760 bp of the nuSSU and 604 bp of the nuLSU rRNA genes and using morphological characters, the genera Koralionastes and Pontogeneia are assigned to the new order Koralionastetales, family Koralionastetaceae, class Sordariomycetes. Koralionastetales is a sister group to Lulworthiales; differences in morphological characters are expressed in the ascospores and the presence/absence of periphyses and paraphyses. A new species of Pontogeneia, P. microdictyi from Microdictyon sp. in the Bahamas, is described.  相似文献   

3.
Gynoecium development is a complex process which is regulated by key factors that control the spatial formation of the apical, medial and basal parts. SHATTERPROOF1 (SHP1) and SHP2, two closely related MADS-box genes, redundantly control the differentiation of the dehiscence zone and promote the lignification of adjacent cells. Furthermore, SHP1 and SHP2 have shown to play an important role in ovule identity determination. The present work identifies a new function for these two genes in promoting stigma, style and medial tissue development. This new role was discovered by combining the shp1 shp2 double mutant with the aintegumenta (ant) and crabs claw (crc) mutants. In quadruple mutant flowers, the inner whorl is composed of unfused carpels which lack almost completely apical and medial tissues, a phenotype similar to the previously reported fil ant and lug ant double mutants.  相似文献   

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5.
Ferret-badgers, genus Melogale, are distributed in the Indochinese region, Java, Bali and NE-Borneo. There are currently four species described each having very similar phenotypes. In March 2005, a living ferret-badger of a different phenotype was confiscated by rangers from Cuc Phuong National Park, Vietnam. This individual died and the carcass was not preserved. In January 2006, a newly deceased individual of the same phenotype was found at the Endangered Primate Rescue Center, Cuc Phuong National Park. Due to several different characteristics these individuals vary greatly from the current species. Thus, we describe an additional species, M. cucphuongensis sp. nov. from northern Vietnam, which occurs sympatrically with M. moschata and M. personata, but differs from both species clearly in skull morphology and other features.Based on a 423 bp-long fragment of the mitochondrial cytochrome b gene, M. cucphuongensis sp. nov. is a member of the genus Melogale and represents a sister lineage to a clade consisting of M. personata and M. moschata.  相似文献   

6.
7.
A multi-locus phylogenetic study of the order Arthoniales is presented here using the nuclear ribosomal large subunit (nuLSU), the second largest subunit of RNA polymerase II (RPB2) and the mitochondrial ribosomal small subunit (mtSSU). These genes were sequenced from 43 specimens or culture isolates representing 33 species from this order, 16 of which were from the second largest genus, Opegrapha. With the inclusion of sequences from GenBank, ten genera and 35 species are included in this study, representing about 18 % of the genera and ca 3 % of the species of this order. Our study revealed the homoplastic nature of morphological characters traditionally used to circumscribe genera within the Arthoniales, such as exciple carbonization and ascomatal structure. The genus Opegrapha appears polyphyletic, species of that genus being nested in all the major clades identified within Arthoniales. The transfer of O. atra and O. calcarea to the genus Arthonia will allow this genus and family Arthoniaceae to be recognized as monophyletic. The genus Enterographa was also found to be polyphyletic. Therefore, the following new combinations are needed: Arthonia calcarea (basionym: O. calcarea), and O. anguinella (basionym: Stigmatidium anguinellum); and the use of the names A. atra and Enterographa zonata are proposed here. The simultaneous use of a mitochondrial gene and two nuclear genes led to the detection of what seems to be a case of introgression of a mitochondrion from one species to another (mitochondrion capture; cytoplasmic gene flow) resulting from hybridization.  相似文献   

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9.
The Abildgaardieae tribe within the family Cyperaceae comprises six or seven genera, among which Abildgaardia, Bulbostylis and Fimbristylis pose a challenge regarding their morphological delimitation. Molecular phylogenetic analyses including species of Abildgaardieae are rare, but in most of those studies, Abildgaardia and Fimbristylis appear as more closely related to each other than to the Bulbostylis genus. Duration of the style base has been one of the most widely used characters for delimiting these three genera. The style base is a persistent structure in most species of Bulbostylis and deciduous in Abildgaardia and Fimbristylis. The reasons why the style base may persist or fall off have been scarcely discussed. The assumption that abscission layers are present in the style base of all three genera and the fact that tracheids have been observed in the style base of Bulbostylis suggest that this structure might have histological complexity. In view of this, a complete ontogenetic and anatomical study of the gynoecium has been carried out for all these three genera. It turned out that the style base is histologically simple in Abildgaardia, Bulbostylis and Fimbristylis and shows similar structure and development in all three genera. The fact that the style base has a shorter duration in Abildgaardia and Fimbristylis than in Bulbostylis might be related to the lower number of sclerotised cells that make up such structures in the mature fruit of the former two genera. Abscission of the style and style base may be the result of much simpler reasons than the differentiation of an abscission layer, resulting merely from mechanical shear force effects. Differences among genera have been observed in the shape of the style base and the development of the style. The histological simplicity of the style base is consistent with the homoplastic appearance of this structure in genera that are not closely related (e.g. Rhynchospora). Because of this, while the presence of the thickened style base seems to be a synapomorphy in species of Abildgaardieae, its persistence on or detachment from the fruit might have emerged repeatedly during this clade evolution and might not be a suitable character for genera delimitation.  相似文献   

10.
The generation of cellular diversity in the nervous system involves the mechanism of asymmetric cell division. Besides an array of molecules, including the Par protein cassette, a heterotrimeric G protein signalling complex, Inscuteable plays a major role in controlling asymmetric cell division, which ultimately leads to differential activation of the Notch signalling pathway and correct specification of the two daughter cells. In this context, Notch is required to be active in one sibling and inactive in the other. Here, we investigated the requirement of genes previously known to play key roles in sibling cell fate specification such as members of the Notch signalling pathway, e.g., Notch (N), Delta (Dl), and kuzbanian (kuz) and a crucial regulator of asymmetric cell division, inscuteable (insc) throughout lineage progression of 4 neuroblasts (NB1-1, MP2, NB4-2, and NB7-1). Notch-mediated cell fate specification defects were cell-autonomous and were observed in all neuroblast lineages even in cells born from late ganglion mother cells (GMC) within the lineages. We also show that Dl functions non-autonomously during NB lineage progression and clonal cells do not require Dl from within the clone. This suggests that within a NB lineage Dl is dispensable for sibling cell fate specification. Furthermore, we provide evidence that kuz is involved in sibling cell fate specification in the central nervous system. It is cell-autonomously required in the same postmitotic cells which also depend on Notch function. This indicates that KUZ is required to facilitate a functional Notch signal in the Notch-dependent cell for correct cell fate specification. Finally, we show that three neuroblast lineages (NB1-1, NB4-2, and NB7-1) require insc function for sibling cell fate specification in cells born from early GMCs whereas insc is not required in cells born from later GMCs of the same lineages. Thus, there is differential requirement for insc for cell fate specification depending on the stage of lineage progression of NBs.  相似文献   

11.
Ambrosia beetles (Coleoptera: Scolytinae) are associated with strictly entomochoric and mutualistic fungi. We studied the mycobiota associated with Scolytodes unipunctatus, ambrosia beetles that infest Cecropia trees in Central America. Isolates were characterized using morphology and rDNA sequences (ITS region, LSU, and SSU rDNA). Four species are described here: Raffaelea scolytodis sp. nov. (Ophiostomatales), Gondwanamyces scolytodis sp. nov., Custingophora cecropiae sp. nov., and Graphium sp. (Microascales). The genus Custingophora is emended to include Knoxdaviesia anamorphs of Gondwanamyces based on uniformity of DNA sequences and phenotype.  相似文献   

12.
Starch grains are a ubiquitous component of plants that have been used in tandem with phytoliths, pollen, and macrofossils to reconstruct past floral diversity. This tool has yet to be fully explored for aquatic plants, specifically seagrasses, which lack phytoliths and are rarely preserved as macrofossils or pollen. If starch grains in seagrasses are morphologically distinct, this method has the potential to improve seagrass identification in the fossil record in such cases where its starch is preserved (e.g. scratches and occlusal surfaces of tooth enamel from seagrass consumers). The goals of this study were twofold: (1) to determine if starch is present in seagrass material and (2) to assess how starch grain morphology differs between different seagrasses.This study focused on four abundant and ecologically distinct seagrasses from the Caribbean: Halodule wrightii, Ruppia maritima, Syringodium filiforme, and Thalassia testudinum. Starch grains were observed in all species except S. filiforme. Grains from H. wrightii are typically observed in side-on orientation, are sub-round to angular, and are fairly small (3-19 μm, end-on). Grains of R. maritima are small spherical grains (4-8 μm) that have a centric hilum and a straight extinction cross with a median angle between the arms of 90°. Grains from T. testudinum are large (9-31 μm, end-on), conical in side-on and round/sub-round in end-on orientation, have a slightly eccentric hilum with an obvious particle, and prominent lamellae.Visual assessment and comparative statistics demonstrate that the morphology of starch grains from T. testudinum, R. maritima, and H. wrightii are significantly different. With more extensive research, there is potential for the positive identification of starch grains from an unknown seagrass. The ability to identify seagrass from starch grains could facilitate the identification of seagrasses in the fossil record and supply information on seagrass evolution and distribution, climate effects on seagrass distribution, and the diets of seagrass consumers.  相似文献   

13.
14.
Dark, septate endophytes (DSE) were isolated from roots and needles of dwarf Picea abies and from roots of Vaccinium spp. growing on a permafrost site in the Jura Mountains in Switzerland. Two of the isolates sporulated after incubation for more than one year at 4 °C. One of them was a hitherto undescribed helotialean ascomycete Phaeomollisia piceae gen. sp. nov., the other was a new species of Phialocephala, P. glacialis sp. nov. Both species are closely related to DSE of the Phialocephala fortinii s. lat.-Acephala applanata species complex (PAC) as revealed by phylogenetic analyses of the ITS and 18S rDNA regions. Morphologically dissimilar fungi, such as Vibrissea and Loramyces species, are phylogenetically also closely linked to the new species and the PAC. Cadophora lagerbergii and C. (Phialophora) botulispora are moved to Phialocephala because Phialocephala dimorphospora and P. repens are the closest relatives. Several Mollisia species were closely related to the new species and the PAC according to ITS sequence comparisons. One DSE from needles of Abies alba and one from shoots of Castanea sativa formed Cystodendron anamorphs in culture. Their identical 18S sequences and almost identical ITS sequences indicated Mollisia species as closest relatives, suggesting that Mollisia species are highly euryoecious.  相似文献   

15.
Torrubiella is a genus of arthropod-pathogenic fungi that primarily attacks spiders and scale insects. Based on the morphology of the perithecia, asci, and ascospores, it is classified in Clavicipitaceae s. lat. (Hypocreales), and is considered a close relative of Cordyceps s. 1., which was recently reclassified into three families (Clavicipitaceae s. str., Cordycipitaceae, Ophiocordycipitaceae) and four genera (Cordyceps s. str, Elaphocordyceps, Metacordyceps, and Ophiocordyceps). Torrubiella is distinguished morphologically from Cordyceps s. lat. mainly by the production of superficial perithecia and the absence of a well-developed stipitate stroma. To test and refine evolutionary hypotheses regarding the placement of Torrubiella and its relationship to Cordyceps s. lat., a multi-gene phylogeny was constructed by conducting ML and Bayesian analyses. The monophyly of Torrubiella was rejected by these analyses with species of the genus present in Clavicipitaceae, Cordycipitaceae, and Ophiocordycipitaceae, and often intermixed among species of Cordyceps s. lat. The morphological characters traditionally used to define the genus are, therefore, not phylogenetically informative, with the stipitate stromata being gained and/or lost several times among clavicipitaceous fungi. Two new genera (Conoideocrella, Orbiocrella) are proposed to accommodate two separate lineages of torrubielloid fungi in the Clavicipitaceae s. str. In addition, one species is reclassified in Cordyceps s. str. and three are reclassified in Ophiocordyceps. The phylogenetic importance of anamorphic genera, host affiliation, and stipitate stromata is discussed.  相似文献   

16.
The ultrastructure of septa and septum-associated septal pore caps are important taxonomic markers in the Agaricomycotina (Basidiomycota, Fungi). The septal pore caps covering the typical basidiomycetous dolipore septum are divided into three main phenotypically recognized morphotypes: vesicular-tubular (including the vesicular, sacculate, tubular, ampulliform, and globular morphotypes), imperforate, and perforate. Until recently, the septal pore cap-type reflected the higher-order relationships within the Agaricomycotina. However, the new classification of Fungi resulted in many changes including revision of existing and addition of new orders. Therefore, the septal pore cap ultrastructure of more than 325 species as reported in literature was related to this new classification. In addition, the septal pore cap ultrastructures of Rickenella fibula and Cantharellus formosus were examined by transmission electron microscopy. Both fungi have dolipore septa associated with perforate septal pore caps. These results combined with data from the literature show that the septal pore cap-type within orders of the Agaricomycotina is generally monomorphic, except for the Cantharellales and Hymenochaetales.It appears from the fungal phylogeny combined with the septal pore cap ultrastructure that the vesicular-tubular and the imperforate type both may have arisen from endoplasmic reticulum. Thereafter, the imperforate type eventually gave rise to the perforate septal pore cap-type.  相似文献   

17.
Four species of tephritid fruit flies, Ceratitis capitata, Bactrocera dorsalis, B. cucurbitae, and B. latifrons were evaluated for toxic, developmental, and physiological responses to the chemosterilant lufenuron. No significant mortality of laboratory strains of the first three species was observed after their exposure up to 50 μg/mL of lufenuron in agar adult diet, whereas B. latifrons adults fed with 50 μg/mL of lufenuron in the diet caused significant mortality compared to the control. Fertility of C. capitata adults fed on 50 μg/mL lufenuron-fortified diet between 7 and 12 days of age was approximately 46% of the no lufenuron control. Fertility of B. dorsalis and B. latifrons adults fed on 50 μg/mL lufenuron-incorporated diet was about 45% and 62% of the control, respectively. Lufenuron did not significantly affect fertility of B. cucurbitae adults. Lufenuron did not affect fecundity of C. capitata and B. dorsalis. Fecundity of B. cucurbitae and B. latifrons was not evaluated due to difficulty to count the eggs laid deep in the agar diet. Larvae fed on a liquid larval diet with ≤ 0.1 μg/mL of lufenuron were also evaluated. Pupal recovery, adult emergence, adult fliers, mating, egg hatch, and egg production of C. capitata were significantly decreased, while for B. dorsalis, pupal recovery, larval duration and adult emergence were affected. No effect of lufenuron on B. cucurbitae larvae was observed. B. latifrons was not performed because shortage of eggs at the time of this research. Lufenuron is a potential agent for management and control of C. capitata and B. dorsalis.  相似文献   

18.
The new species Pelargonium elandsmontanum is a local endemic from Elandsberg Nature Reserve near Malmesbury in the Western Cape Province, South Africa. One of six species of sect. Hoarea with just the posterior two petals developed, it resembles P. ternifolium in its trifoliolate leaves and pink petals but is distinguished from that species by the short, stout petioles, rhombic, acute leaflets with the upper surface glabrous or with spreading hairs (vs cuneate, apically incised leaflets with both surfaces adpressed-hairy), and five (vs four) fertile stamens.  相似文献   

19.
The origin of Hordelymus genome has been debated for years, and no consensus conclusion was reached. In this study, we sequenced and analyzed the RPB2 (RNA polymerase subunit II) gene from Hordelymus europaeus (L.) Harz, and its potential diploid ancestor species those were suggested in previous studies. The focus of this study was to examine the phylogenetic relationship of Hordelymus genomes with its potential donor Hordeum, Psathyrostachys, and Taeniatherum species. Two distinguishable copies of sequences were obtained from H. europaeus. The obvious difference between the two copies of sequences is a 24 bp indel (insertion/deletion). Phylogenetic analysis showed a strong affinity between Hordeum genome and Hordelymus with 85% bootstrap support. These results suggested that one genome in tetraploid H. europaeus closely related to the genome in Hordeum species. Another genome in H. europaeus is sister to the genomes in Triticeae species examined here, which corresponds well with the recently published EF-G data. No obvious relationship was found between Hordelymus and either Ta genome donor, Taeniatherum caput-medusae or Ns genome donor, Psathyrostachys juncea. Our data does not support the presence of Ta and Ns genome in H. europaeus, and further confirms that H. europaeus is allopolyploid.  相似文献   

20.
In this work M. galloprovincialis and O. edulis specimens were surveyed for a pathological study in the Gulf of Naples (Mediterranean sea, Campania Region, southern Italy). Clusters of Nocardia sp.-like cells were observed in histological slides. PCR amplification, sequencing and in situ hybridization were carried out in order to corroborate Nocardia species identification for both hosts. Blast results showed a 99% of maximum identity with Nocardia crassostreae sequences in Genbank. This is the first report of N. crassostreae in the new host M. galloprovincialis and, in a new area, the Mediterranean Sea.  相似文献   

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