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1.
《Mycoscience》2014,55(1):1-4
Species of the genus Acaulospora are partly characterized by the production of ‘acaulosporoid’ spores. The simultaneous formation of glomoid and acaulosporoid spores by some species in the Glomeromycota has been used as a basis for taxonomic classification. We report the presence of both glomoid and acaulosporoid spores in four Acaulospora species. Analysis of the 18S rRNA gene confirmed that only A. spinosa was present in a pot culture that produced two morphs. The functional significance of dimorphic spore production is unknown but the production of blastic spores is not a characteristic that can have any significance as a taxonomic character.  相似文献   

2.
We examined the phylogenetic position of an arbuscular mycorrhizal fungus which produces two types of spore,Acaulospora gerdemannii andGlomus leptotichum, based upon the DNA sequence of the 18S rRNA gene. DNA was extracted separately from bothGlomus-like orAcaulospora-like spores and partial 5′-terminus segments of 18S rRNA gene were amplified by the PCR method. Several clones derived from each spore type were sequenced and compared. The sequences from both spore types agreed well, confirming that these morphologically different spores were formed by the same fungus. Nucleotide substitutions were found among several clones, suggesting polymorphism of the rRNA gene in glomalean fungi. Further phylogenetic analysis based upon the whole sequence of the 18S rRNA gene showed thatA. gerdemannii may be within the order Glomales but is far from the fungi that have been analyzed and probably should be in a new family.  相似文献   

3.
Kaonongbua W  Morton JB  Bever JD 《Mycologia》2010,102(6):1497-1509
In a phylogenetic study of arbuscular mycorrhizal fungal species in Acaulospora (Acaulosporaceae, Glomeromycota) we discovered that species classified in genus Kuklospora, a supposed sister clade of Acaulospora, did not partition as a monophyletic clade. Species in these two genera can be distinguished only by the position of the spore relative to a precursor structure, the sporiferous saccule, as either within (entrophosporoid) or laterally (acaulosporoid) on the saccule subtending hypha. Subsequent spore differentiation follows identical patterns and organization. Molecular phylogeny reconstructed from nrLSU gene sequences, together with developmental data, support the hypothesis that the entrophosporoid mode of spore formation evolved many times and thus represents a convergent trait of little phylogenetic significance. Therefore genus Kuklospora is rejected as a valid monophyletic group and it is integrated taxonomically into genus Acaulospora. Thus Acaulospora colombiana and Acaulospora kentinensis are erected as new combinations (formerly Kuklospora colombiana and Kuklospora kentinensis). Mode of spore formation is demoted from a genus-specific character to one that is included with other traits to define Acaulospora species. In addition we describe a new AM fungal species, Acaulospora colliculosa (Acaulosporaceae), that originated from a tallgrass prairie in North America. Field-collected spores of A. colliculosa are small (<100 μm diam), hyaline or subhyaline to pale yellow and form via entrophosporoid development based on structure and organization of cicatrices and attached hyphae. Each spore consists of a bilayered spore wall and two bilayered inner walls. A germination orb likely forms after the completion of spore development to initiate germination, but this structure was not observed. A character distinguishing A. colliculosa from other Acaulospora species is hyaline to subhyaline hemispherical protuberances on the surface of the outer spore wall layer. A phylogeny reconstructed from partial nrLSU gene sequences unambiguously placed A. colliculosa in the Acaulospora clade.  相似文献   

4.
The species composition of cyanobacteria from 12 lakes of Southern Transbaikal Region was studied. In the studied lakes, a total of 28 species of cyanobacteria were detected, including 10 species previously not retrieved from the lakes of Southern Transbaikal Region. The morphological and ecophysiological characteristics, as well as the phylogenetic position, of pure cyanobacterial cultures were determined. According to the results of 16S rRNA sequencing, the Cya 1, Cya 2, and Cya 10 cultures were identified as representatives of the genus Phormidium; the Cya 5 and Cya 6 cultures were assigned to the genus Nodularia. On the basis of its morphological properties, the Cya 4 culture was identified as Pseudanabaena frigida. The studied microorganisms were moderate alkaliphiles and could grow within a broad salinity range (0–100 g/l NaCl).  相似文献   

5.
Saussurea esthonica Baer ex Rupr. is a species of the genus Saussurea that is found in Estonia, Latvia and the Leningrad region in Russia. Only two populations have been identified in Latvia, and it is protected at the national level. The taxonomic relationships within this genus are unclear, and the majority of phylogenetic studies of this genus have been undertaken on species found in Asia. The relationship of S. esthonica to the other Saussurea species is equally unclear, with some suggestions that this species should be regarded as a subspecies of S. alpina. Two different molecular marker techniques, iPBS and ITS sequencing, were utilised to investigate the phylogeny of S. esthonica and its relationship with other Saussurea species, including three European species: S. alpina, S. pygmaea and S. discolor. The phylogeny obtained with the iPBS markers was similar to that obtained with the ITS sequences. The phylogenies obtained were broadly consistent with previous morphological classification, with S. alpina, S. esthonica and S. discolor clustering together. S. pulchella, S. albescens and S. candicans also formed one discrete cluster. The taxonomic status of S. esthonica was not unambiguously determined, with Norwegian and Italian S. alpina populations clustering with Latvian and Estonian S. esthonica populations, and the Austrian S. alpina populations clustering with Austrian S. discolor populations.  相似文献   

6.
Knowledge about the presence and diversity of arbuscular mycorrhizal fungi (AMF) in a specific area is an essential first step for utilizing these fungi in any application. The community composition of AMF in intensively managed agricultural soil in the Sichuan Province of southwest China currently is unknown. In one set of samples, AMF were trapped in pot cultures from 40 fields growing legumes in the Panxi region, southeast Sichuan. In a second set of samples, the MPN method with four-fold dilutions and maize as host was used to estimate infective propagules in soil from another 50 agricultural sites throughout the province. Soil types were heterogeneous and were classified as purple, yellow, paddy and red. Crops at each site were either maize, wheat or sweet orange. From this set of soil, AMF spores were also extracted and identified. Including all ninety soils, thirty glomeromycotan species in Glomus (20 species), Acaulospora (four species), Scutellospora (three species), Ambispora (one species), Archaeospora (one species) and Paraglomus (one species) were identified. Yellow, red and purple soils yielded similar numbers of AMF species, while AMF species diversity was clearly lower in paddy soil. In trap culture soils, the most frequent species were Glomus aggregatum or Glomus intraradices, Glomus claroideum and Glomus etunicatum. The species Acaulospora capsicula, Acaulospora delicata, G. aggregatum (or intraradices), G. claroideum, Glomus epigaeum, G. etunicatum, Glomus luteum, Glomus monosporum, Glomus mosseae and Glomus proliferum were successfully cultured as single-species pot cultures in Plantago lanceolata. The three most frequent species in field soils were G. mosseae, Glomus caledonium and Glomus constrictum. MPN values varied between 17 and 3334 propagules 100 g soil−1 among the fifty field sites sampled. Regression analysis, including host&soil, log(P) and pH as explanatory variables explained 59% of the variation in log(MPN). The highest MPN estimates were found in purple soil cropped with maize and citrus, 324 and 278 propagules 100 g soil−1, respectively. The lowest MPN value, 54 propagules 100 g soil−1, was measured in wheat in purple and yellow soil. Despite intensive agricultural management that can include often repeated tillage, our examination of 90 agricultural sites revealed that soils of the Sichuan region have moderate to high numbers of infective AMF propagules as well as a high AMF species diversity. This opens possibilities for further studies and utilization of AMF in agriculture and horticulture in the Sichuan province, People’s Republic of China.  相似文献   

7.
 The isolation of vesicular-arbuscular mycorrhizal (VAM) fungi from natural (savanna, rocky hill, wetland and rainforest) and disturbed (minesite) habitats in a seasonally-dry tropical region in the Northern Territory of Australia into open-pot cultures was undertaken to supplement knowledge about the diversity of these fungi. This experiment considered factors affecting the diversity of fungi obtained in trap cultures started using diluted soil from field sites and two host plants. A range of soil phosphorus and other nutrient levels from severely deficient to sufficient for maximal growth was used to determine the impact of nutrition on mycorrhizal associations of sorghum (Sorghum sp.) and clover (Trifolium subterraneum). Soil cores taken from pots at 6-week intervals provided roots and soil to assess mycorrhiza formation and sporulation without substantial damage to plants. The identification of VAM fungi to genus by observing morphological patterns within clover roots revealed substantial differences in fungus populations between soils and a moderate effect of nutrient levels on fungal diversity. Changes in the proportion of different fungi in roots over the 31 weeks of the experiment were also observed. Glomus spp. were initially the most abundant fungi within roots, but Scutellospora spp. gradually became more dominant at later harvests, while colonisation by Acaulospora spp. was limited at all times. For both clover and sorghum, sporulation was limited and was dominated by single species of Scutellospora and Acaulospora. This contrasted with the much higher diversity of spore types in the original field soils.  相似文献   

8.
We performed a comparative morphological and molecular study on oxytrichid and urostylid stichotrichs (=part of the former hypotrichs). Included are new small subunit (18S) ribosomal RNA (rRNA) gene sequences from five rare oxytrichids (Gonostomum namibiense, Cyrtohymena citrina, Hemiurosoma terricola, Onychodromopsis flexilis, Orthoamphisiella breviseries) and published sequences, based on cultures provided by the senior author, of two key stichotrichid genera, viz., Gastrostyla and Engelmanniella. These and other sequences, altogether 27 species representing 23 genera, were used to analyze how 18S rRNA-based phylogenetic trees can be reconciled with the morphological and ontogenetical data. In 18S rRNA trees, the oligotrichine family Halteriidae invariably clusters within the oxytrichid clade, usually near Oxytricha granulifera, type species of the genus. This position is hardly supported by morphological and ecological evidence and, especially, it contradicts the current ontogenetic findings; possibly, it is an artifact caused by taxa undersampling and/or special molecular evolutionary events. In contrast, most morphological and DNA sequence data of the stichotrichs can be harmonized with the CEUU (Convergent Evolution of Urostylids and Uroleptids) hypothesis which suggests that the urostylid midventral pattern evolved from an oxytrichine ancestor, developing a second time within the Oxytrichidae. The systematic position of one of the two key genera could be clarified with the 18S rRNA sequences: Gastrostyla is a stylonychine oxytrichid. Based on the molecular data and a reassessment of ontogenesis, a new genus, Styxophrya nov. gen., is established for Onychodromus quadricornutus Foissner, Schlegel & Prescott, 1987.  相似文献   

9.
An alkalitolerant and halotolerant bacterium, designated strain Sharm was isolated from a salt lake inside Ras Muhammad. The morphological, physiological and genetic characteristics were compared with those of related species of the genus Halomonas. The isolate grew optimally at pH 7.0, 5–15% NaCl at 35°C. The cells were Gram-negative rods, facultative anaerobes. They accumulated glycine-betaine, as a major osmolyte, and ectoine and glutamate as minor components. The strain SharmT biosynthetised α-glucosidase. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and a novel phosphoglycolipid as major components. Ubiquinone with nine repetitive unities (Q9) was the only quinone found and, nC16:0 and C19:0 with cyclopropane were the main cellular fatty acids, accounting for 87.3% of total fatty acids. The G + C content of the genomic DNA was 64.7 mol %. The 16S rRNA sequence analysis indicated that strain Sharm was a member of the genus Halomonas. The closest relatives of the strain Sharm were Halomonas elongata and Halomonas eurihalina. However, DNA–DNA hybridisation results clearly indicated that strain Sham was a distinct species of Halomonas. On the basis of the evidence, we propose to assign strain Sharm as a new species of the genus Halomonas, H. sinaiensis sp. nov, with strain SharmT as the type strain (DSM 18067T; ATCC BAA-1308T). The EMBL accession number for the 16S rRNA sequence of Halomonas sinaiensis strain SharmT is AM238662.  相似文献   

10.
11.
We describe a new species of Nomimoscolex from the Amazon siluriform fishes Brachyplatystoma filamentosum, B. flavicans and B. vaillanti. It differs from N. piraeeba in a lower mean number of testes, the paramuscular position of the vitelline follicles, the ovarian width/proglottis width ratio and the cirrus-pouch length/proglottis width ratio. Protein electrophoresis assays performed for 25 enzymatic systems showed that specimens of N. suspectus n. sp. from the three host species form a homogenous population which was genetically isolated from N. piraeeba and N. dorad. Moreover, the latter two species, synonymised by Rego (1991) because of their close morphological similarity, could be separated at eight loci. We thus restore N. dorad as a valid species. We finally examined the composition of the genus Nomimoscolex using DNA sequences from the 5.8S rRNA, ITS-2 and 28S rRNA nuclear ribosomal genes and a matrix of 24 morphological characters. Phylogenetic relationships were inferred for nine species of the genus, five members of other monticelliid genera and two outgroup species. The results of the phylogenetic analyses performed on morphological and molecular characters converged with those from allozyme studies and showed that N. suspectus, N. piraeeba and N. dorad clustered in a distinct clade that excluded other members of the genus. We therefore recognised them as an aggregate of species to reflect an isolation supported by both morphological and genetic data. Because relationships among the remaining Nomimoscolex representatives and other genera were generally poorly resolved, regardless of the database analysed, no action was taken to reorganise them into alternative groupings.  相似文献   

12.
A moderate halophile, strain X50T, was isolated from mustard kimchi, a traditional Korean fermented food. The organism grew under conditions ranging from 0–15.0% (w/v) NaCl (optimum: 3.0%), pH 7.0–10.0 (optimum: pH 9.0) and 15–45°C (optimum: 37°C). The morphological, physiological, and biochemical features and the 16S rRNA gene sequences of strain X50T were characterized. Colonies of the isolate were creamcolored and the cells were rod-shaped. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain X50T belongs to the genus Oceanobacillus and is closely related phylogenetically to the type strain O. iheyensis HTE831T (98.9%) and O. oncorhynchi subsp. oncorhynchi R-2T (97.0%). The cellular fatty acid profiles predominately included anteiso-C15:0 and iso-C15:0. The G+C content of the genomic DNA of the isolate was 37.9 mol% and the major isoprenoid quinone was MK-7. Analysis of the 16S rRNA gene sequences, DNA-DNA relatedness and physiological and biochemical tests indicated genotypic and phenotypic differences among strain X50T and reference species in the genus Oceanobacillus. Therefore, strain X50T was proposed as a novel species and named Oceanobacillus kimchii. The type strain of the new species is X50T (=JCM 16803T =KACC 14914T =DSM 23341T).  相似文献   

13.
Acaulospora alpina sp. nov. forms small (65-85 microm diam), dark yellow to orange-brown spores laterally on the neck of hyaline to subhyaline sporiferous saccules. The spores have a three-layered outer spore wall, a bi-layered middle wall and a three-layered inner wall. The surface of the second layer of the outer spore wall is ornamented, having regular, circular pits (1.5-2 microm diam) that are as deep as wide and truncated conical. A "beaded" wall layer as found in most other Acaulospora spp. is lacking. The spore morphology of A. alpina resembles that of A. paulinae but can be differentiated easily by the unique ornamentation with the characteristic pits and by the spore color. A key is presented summarizing the morphological differences among Acaulospora species with an ornamented outer spore wall. Partial DNA sequences of the ITS1, 5.8S subunit and ITS2 regions of ribosomal DNA show that A. alpina and A. paulinae are not closely related. Acaulospora lacunosa, which has similar color but has generally bigger spores, also has distinct rDNA sequences. Acaulospora alpina is a characteristic member of the arbuscular mycorrhizal fungal communities in soils with pH 3.5-6.5 in grasslands of the Swiss Alps at altitudes between 1800 and 2700 m above sea level. It is less frequent at 1300-1800 m above sea level, and it so far has not been found in the Alps below 1300 m or in the lowlands of Switzerland.  相似文献   

14.
Stenomitos terricola FBCC-A190 was collected from soils around the trees of Mt. Gwanggyo, located in Yeongtong-gu, Suwon-si, Gyeonggi-do. S. terricola FBCC-A190 is a thin and simple filament with a cell length that is longer than its width. It has a thin and firm sheath, exhibiting a blue-green color. Species belonging to genus Stenomitos is semi-cryptic species with slight morphological differences from each other. They were confirmed as Stenomitos species by analysis using 16S rRNA and 16S–23S ITS. A monophyletic cluster was formed with the previously reported genus Stenomitos, with 16S rRNA gene sequences sharing similarities of 95.9–97.9% except for S. pantisii TAU-MAC 4318. In addition, 16S–23S ITS gene sequencing showed tRNAAla, tRNAIle and V2, similar to the previously reported genus Stenomitos. From these results, Stenomitos terricola sp. nov. was proposed as a new species belonging to genus Stenomitos.  相似文献   

15.
16.
Two new species of the methanol assimilating ascosporic yeast genus Komagataella are described. Komagataella populi sp. nov. (NRRL YB-455, CBS 12362, type strain, MycoBank accession number = 564110) was isolated from an exudate on a cottonwood tree (Populus deltoides), Peoria, Illinois, USA, and Komagataella ulmi sp. nov. (NRRL YB-407, CBS 12361, type strain, MycoBank accession number = 564111) was isolated from the exudate on an elm tree (Ulmus americana), also growing in Peoria, Illinois. The species were resolved from divergence in gene sequences for domains D1/D2 LSU rRNA, ITS1-5.8S-ITS2, mitochondrial small subunit rRNA, RNA polymerase subunit 1 and translation elongation factor-1α. Species of Komagataella assimilate few carbon compounds and are unlikely to be resolved from differences in standard growth and fermentation tests. For this reason, separation of species is dependent on gene sequence analysis.  相似文献   

17.
A Gram-positive bacterium, designated M-GX18T, was isolated from the rhizosphere soil of mango (Guangxi Province, China). The isolate produced nematicidal volatile compounds with activities against the root-knot nematode Meloidogyne incognita. The organism was motile, catalase- and oxidase-positive, spore-forming and rod shaped. The predominant menaquinone was MK-7 and the major cellular fatty acid profiles were iso-C15:0, anteiso-C15:0 and iso-C16:0. The DNA G+C content was 38.9%. A phylogenetic analysis based on 16S rRNA gene sequences showed that this organism represented a new species of the genus Lysinibacillus. Strain M-GX18T exhibited high 16S rRNA gene sequence similarity with its closest neighbors Lysinibacillus sphaericus (98.5%), Lysinibacillus fusiformis (98.1%) and Lysinibacillus xylanilyticus (98.6%). The physiological, biochemical and chemotaxonomic data, including DNA–DNA hybridization relatedness data, indicate that strain M-GX18T can be distinguished from all the related species of the genus Lysinibacillus. Therefore, on the basis of the polyphasic taxonomic data presented, a new species of the genus Lysinibacillus, Lysinibacillus mangiferahumi, with the type strain M-GX18T (=DSM 24076T = CCTCC AB 2010389T) is proposed.  相似文献   

18.
Hevea brasiliensis is one of the important economic trees with a great economic value for natural rubber production. Symbiosis between roots of H. brasiliensis and arbuscular mycorrhizal fungi (AMF) is widely recognized, and can provide a range of benefits for both of them. Hainan Island harbors is one of the largest plantations of H. brasiliensis in China, whereas the information regarding the diversity of AMF in the rhizosphere of H. brasiliensis on this island is scarce. The diversity of AMF species in the rhizosphere of rubber tree plantations in Hainan was investigated in this study. A total of 72 soil samples from the rhizosphere of H. brasiliensis RY7-33-97 were collected. These included 48 samples from plantations in 11 cities or counties that had been planted for 15–25 years, and 24 samples from a demonstrating plantation site of the China National Rubber Tree Germplasm Repository representing plantations with tree plantation ages from one to 40 year-old. Collectively, a total of 68 morphotypes of AMF, belonging to the genera of Archaeospora (1), Glomus (43), Acaulospora (18), Entrophospora (3), Scutellospora (2), and Gigaspora (1) were isolated and identified, as per morphological characteristics of spores presented in the collected soil samples. Glomus (Frequency, F = 100%) and Acaulospora (F = 100%) were the predominant genera, and A. mellea (F = 63.9%) and A. scrobiculata (F = 63.9%) were the predominant species. AMF species differed significantly among collected sites in spore density (SD, 290.7–2,186.7 spores per 100 g dry soil), species richness (SR, 4.3–12.3), and Shannon-Weiner index of diversity (H, 1.24–2.24). SD was negatively correlated with available phosphorus level in the soil; SR was positively correlated with soil total phosphorus content; and H was positively correlated with levels of soil organic matter and total phosphorus. Similarly, SD, SR, and H were also correlated with H. brasiliensis plantation age, and an increasing trend was observed up to 40 years. These results suggest that the AMF community was complex and ubiquitous in the island plantation ecosystems of H. brasiliensis, with high species abundance and diversity. Soil factors and plantation age dramatically affected AMF diversity at species level.  相似文献   

19.
A novel Gram-negative and rod-shaped bacterium, designated N8T, was isolated from tidal flat sediment. Phylogenetic analysis based on 16S rRNA gene sequences showed that N8T strain is associated with the family Phyllobacteriaceae: two uncultured clones (98.4 and 99.8% 16S rRNA gene sequence similarity) and the genus Mesorhizobium (≤97.0%). The novel strain formed a separate clade with uncultured clones in the phylogenetic tree based on 16S rRNA gene sequences. Cellular fatty acid profiles predominately comprised C18:1 ω7c and C19:0 cyclo ω8c. The major isoprenoid quinone is ubiquinone-10 and genomic DNA G+C content is 53.4 mol%. The polyphasic taxonomic study indicates that the novel strain N8T represents a novel species of the new genus in the family Phyllobacteriaceae, named Aliihoeflea aestuarii. The type strain is N8T (= KCTC 22052T= JCM 15118T= DSM 19536T).  相似文献   

20.
Clone library-based studies have shown that almost all lumbricid earthworm species harbour host-specific symbiotic bacteria belonging to the novel genus Verminephrobacter in their nephridia (excretory organs). To date the only described representative from this genus is Verminephrobacter eiseniae, the specific symbiont of the earthworm Eisenia fetida. In this study two novel rod-shaped, non-endosporeforming, betaproteobacterial symbionts were isolated from the nephridia of two closely related earthworm species. Both isolates were affiliated with the genus Verminephrobacter by 16S rRNA gene sequence analysis. Similarly to V. eiseniae, the two isolates grew aerobically with a preference for low oxygen concentrations on a range of sugars, fatty acids and amino acids and fermentatively on glucose and pyruvate. These phenotypes match well with the conditions reported or inferred for the nephridial environment. Based on 16S rRNA gene similarity, DNA–DNA hybridization value and phenotypic characteristics the two isolates are clearly distinct from V. eiseniae. Phenotypic characteristics could not clearly differentiate the two strains as separate species but a low DNA–DNA hybridization value of 57.3%, their earthworm host specificity, differing temperature ranges and pH optima suggest that they represent two subspecies of a novel species of Verminephrobacter. For this species, the name V. aporrectodeae sp. nov. is proposed, with the two subspecies V. aporrectodeae subsp. tuberculatae (type strain, At4T = DSM 21361T = LMG 25313T) and V. aporrectodeae subsp. caliginosae (type strain, Ac9T = DSM 21895T = LMG 25312T) isolated from the nephridia of the earthworms Aporrectodea tuberculata and A. caliginosa, respectively.  相似文献   

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