Four powdery mildew species with catenate conidia infect Galium: molecular and morphological evidence

The Erysiphaceae are a group of obligately biotrophic fungi that cause powdery mildew disease of angiosperms. Due to their inability to be cultured on artificial media, the taxonomy of the Erysiphaceae has generally been based on the morphological characteristics of fresh and herbarium specimens. Thus, several morphological species with wide host ranges have long been maintained in this family, even though they clearly consist of several biological species. Erysiphe galii has been known as a powdery mildew of Galium spp. Recently, the former E. galii var. galii has been reassessed as Neoerysiphe galii and E. galii var. riedliana as Golovinomyces riedlianus, along with a taxonomic revision of the generic concept of the Erysiphaceae. The present study was conducted to evaluate the validity of the taxonomic revision of the two varieties of E. galii. During the course of this study, we found that the Galium powdery mildews consist of at least four different species, viz. Neoerysiphe galii, Golovinomyces orontii, G. riedlianus, and an unknown species collected in Argentina. The latter species is described as a new species, Golovinomyces calceolariae. The three species belonging to Golovinomyces are morphologically very similar to each other, i.e. the discrimination between them is rather difficult. The morphological differences of the three Golovinomyces species of Galium are discussed.     

Taxonomic patterns in amino-acids of Acacia seed globulins

Amino-acid analyses of seed globulins from 14 Australian Acacia species show a taxonomic pattern involving variation in the proportions of glutamic acid, isoleucine, threnone and valine. The results support recent taxonomic treatments of the genus, and imply that amino-acid patterns may be usefully predictable in other legumes.     

Pollen morphology of Chinese Curcuma L. and Boesenbergia Kuntz (Zingiberaceae): Taxonomic implications

In order to find new non-molecular evidence to support the phylogenetic and taxonomic position, pollen grains of 20 populations of 16 species of Chinese Curcuma L. and Boesenbergia Kuntz (Zingiberaceae) were investigated under SEM and TEM. The pollen grains are spherical and ovoid, nonaperturate. The pollen wall is composed of a very thin exine and a thick intine. The exine is psilate or echinate. The intine consists of two layers, i.e., a thick, channeled layer (exintine) and an inner homogenous layer (endintine). The results reveal morphological congruence between the pollen grains of species of Curcuma, which according to DNA sequence data appears to be a polyphyletic genus. However the uniform pollen morphology in Curcuma provides no evidence to divide this genus into separate taxonomic entities. Our results on pollen morphology also do not provide any additional evidence to either unite or segregate Boesenbergia albomaculata and Curcumorpha longiflora in the same genus and demonstrate that more taxonomic data on the genus Boesenbergia and its relatives are needed before a final decision can be made.     

Multilocus analysis reveals diversity in the genus Tissierella: Description of Tissierella carlieri sp. nov. in the new class Tissierellia classis nov.

The genus Tissierella and its relatives Tepidimicrobium, Soehngenia and Sporanaerobacter comprise anaerobic Gram-positive bacilli classified along with Gram-positive cocci in a family with controversial placement designated as incertae sedis XI, in the phylum Firmicutes. We performed a top-down reappraisal of the taxonomy from the phylum to the species level within the genus Tissierella. Reconstruction of high-rank 16S rRNA gene-based phylogenies and their interpretation in a taxonomic purpose allowed defining Tissierellia classis nov. within the phylum Firmicutes while the frames of Tissierellales ord. nov. and Tissierellaceae fam. nov. have to be further strengthened. For species delineation in the genus Tissierella, we studied a population of clinical strains. Beside Tissierella praeacuta, a sub-population of five strains formed a clade in multilocus phylogenies (16S rRNA, cpn60, tpi, recA and spo0A genes). Data such as 16S rRNA gene similarity level, population structure, chromosome organization and murein type indicated that this clade corresponded to a novel species for which the name Tissierella carlieri sp. nov. is proposed, with type strain LBN 295^T = AIP 268.01^T = DSM 23816^T = CCUG 60010^T. Such an approach, associating a phylogenetic reappraisal of high-level taxonomic ranks with weak taxonomic structure and a population study for genus and species delineation is needed to strengthen the taxonomic frame of incertae sedis groups in the phylum Firmicutes.     

C-Glycosylxanthones in the Fern Genus Athyrium

The C-glycossylxanthones, mangiferin and isomangigerin, have been detected in three species of Athyrium but appeared to be absent in 55 other species. The compounds appear to be of little value as taxonomic characters in the genus Athyrium or the subfamily Athyioideae.     

Alkaloid distribution in some new world Lupinus species

Alkaloidal profiles of 21 Lupinus species indigenous to North and South America have been determined. Nineteen quinolizidine alkaloids were identified, including aphyllidine and N-methylcytisine, which have not previously been found in the genus. Two dipiperidine alkaloids were also detected. The pattern of alkaloidal distribution is related to a taxonomic classification of the genus.     

Anthochlor pigments and floral UV patterns in the genus Bidens

The occurrence of floral UV absorption-reflection patterns in Bidens laevis is due to a spatial segregation of anthochlor pigments in the flower head. Interspecific, UV pattern polymorphism within this genus falls generally along taxonomic (sectional) lines.     

Karyomorphology and GC-rich heterochromatin pattern in Passiflora (Passifloraceae) wild species from Decaloba and Passiflora subgenera

Thirteen wild species of Passiflora were analyzed using conventional and CMA/DA/DAPI staining to evaluate the karyotype diversity between and within the subgenus Decaloba and Passiflora. The karyotypic features indicate that both subgenera have a conserved chromosome number, as reported before for several species. Submetacentric (sm) chromosomes were found in species from both subgenera, suggesting that sm chromosomes are not restricted to a particular subgenus. The analysis of the karyotypic heterogeneity enabled to distribute the species in three groups, but with no support to phylogenetic and taxonomic levels. The application of fluorochromes allowed for the visualization of CMA⁺/DAPI⁻ blocks, which in our studies always correlated with the occurrence of satellites, showing that occurrence of two chromosome pairs with satellites per cell is a characteristic shared by some species from both subgenera. This feature does not always have relationship with the basic chromosome number. The data found in this study will help to understand the phylogeny, cytotaxonomy, and evolution of the genus Passiflora showing that karyotypic variation can be seen between and within the subgenus Decaloba and Passiflora.     

Phylogeny and phylogeography of the genus Patella based on mitochondrial DNA sequence data

Although some molecular phylogenies of Patella species have been published in recent years, unresolved questions concerning the phylogeny and taxonomy of this genus still remain. We sequenced the mitochondrial genes cytochrome c oxidase subunit I, 12S rRNA and 16S rRNA for all Patella species (Patella vulgata, Patella depressa, Patella candei, Patella caerulea, Patella lugubris, Patella ferruginea, Patella pellucida and the continental and Macaronesian forms of Patella ulyssiponensis and Patella rustica) and Cymbula safiana. Our results revealed the occurrence of five strongly supported clades, although relationships between these are not well supported. According to our data P. vulgata is a genetically distinct lineage and the close phylogenetic relationship between this species and P. depressa, found in previous mitochondrial DNA studies, is not supported. The Mediterranean Sea and the Macaronesian Islands seem to have played an important role in the speciation and diversification of this genus, although different clades show different phylogeographic patterns. Our dataset point to the necessity of a taxonomic revision, as P. candei is paraphyletic relative to P. lugubris.     

A new clade of Mesorhizobium nodulating Alhagi sparsifolia

We isolated 33 nodule bacteria from the legume Alhagi sparsifolia growing in the desert of northwest China. They fell into three groups by restriction analysis of their rrs (small subunit ribosomal RNA) genes, and these, together with dnaK and dnaJ genes, were sequenced from representative isolates to assess their taxonomic position by phylogenetic analysis. The bacteria in each group belonged to different lineages that might represent three different new Mesorhizobium species, two of which form a novel clade very distinct from other species in the genus. Most A. sparsifolia symbionts harboured closely related nodA and nodC genes forming new lineages. The presence of these closely related symbiosis genes in various genomic backgrounds and the incongruence observed between the different gene phylogenies indicate a history of horizontal gene transfer of symbiosis genes between the A. sparsifolia symbionts.     

The distribution of Rhododendrin in birch (Betula) species

Rhododendrin (as rhododendrol) was identified in hydrolyzed bark of 14 species of birch. Betula, representing all taxonomic categories in the genus. Only B. lenta and B. nigra of Subsection Costatae lacked this compound.     

Species identification in the genus Saprolegnia (Oomycetes): Defining DNA-based molecular operational taxonomic units

The lack of a robust taxonomy in the genus Saprolegnia is leading to the presence of incorrectly named isolates in culture collections and of an increasing number of misassigned sequences in DNA databases. Accurate species delimitation is critical for most biological disciplines. A recently proposed approach to solve species delimitation (taxonomic diagnosis system) of difficult organisms is the definition of molecular operational taxonomic units (MOTUs). We have used 961 sequences of nrDNA ITS from culture collections (461 sequences) and GenBank (500 sequences), to perform phylogenetic and clustering optimization analyses. As result, we have identified 29 DNA-based MOTUs in agreement with phylogenetic studies. The resulting molecular clusters support the validity of 18 species of Saprolegnia and identify 11 potential new ones. We have also listed a number of incorrectly named isolates in culture collections, misassigned species names to GenBank sequences, and reference sequences for the species. We conclude that GenBank represents the main source of errors for identifying Saprolegnia species since it possesses sequences with misassigned names and also sequencing errors. The presented taxonomic diagnosis system might help setting the basis for a suitable identification of species in this economically important genus.     

Hamamelose and its derivatives as chemotaxonomic markers in the genus Primula

About 550 species of vascular plants as well as a few mosses were checked for the occurrence of hamamelose, the corresponding alcohol hamamelitol and a galactoside of the latter, clusianose. Hamamelose was found in most of the species investigated. It provides therefore no useful character for chemotaxonomic purposes. Hamamelitol, however, could only be detected in the genus Primula and was therefore more useful. Small amounts of hamamelitol were found in the leaves of species from the subgenera Auganthus, Aleuritia and Auricula but not from Primula and Sphondylia. Clusianose and large amounts of hamamelitol are produced by species of 4 subsections of the section Auricula, but not by species of the subsections Auricula and Erythrodrosum. A taxonomic separation of the two latter from the 4 former subsections is suggested. The taxonomic position of Primula allionii should be reconsidered, since neither clusianose nor hamamelitol could be demonstrated in this species, whereas the other species of the subsection Rhopsidium do contain these carbohydrates.     

Ecological considerations of amino acids and flavonoids in Sarracenia species

Leaf extracts of 43 plants representing all 10 species of the genus Sarracenia were analyzed by 2D-PC, high voltage electrophoresis and G. C., for their amino acids and flavonoids. All species contained only low concentrations of common amino acids and common flavonoids. The taxonomic and ecological significance of these results are discussed.     

Systematic significance of xanthones,benzophenones and biflavonoids in Garcinia

Various parts of ten African species of Garcinia produce a range of xanthones, biflavonoids and lactones. Condensed tannins based on procyanidin are also a major feature of some of the species examined and these tend to be relatively deficient in biflavonoids. Distribution of compounds between plant parts can vary markedly but, in general, the distribution of xanthones, biflavonoids and benzophenones among these and other African species relates well to classical taxonomic divisions. However, when Asian species are included in the analysis only the biflavonoids appear to show general promise as taxonomic markers within the genus. All three classes of compounds seem to possess value as taxonomic markers at the supra-generic level within the subfamily Clusioideae.     

Genotypic and phenotypic variation among Lysobacter capsici strains isolated from Rhizoctonia suppressive soils

Four Gram-negative bacterial strains, recovered from clay soils cultivated with different crops in the Netherland, were subjected to a polyphasic taxonomic study in order to clarify their taxonomic status. Comparative analysis of the 16S rRNA gene sequences revealed that they belong to the genus Lysobacter and to be highly related to the type strains of L. antibioticus DSM 2044^T, L. gummosus DSM 6980^T, and L. capsici DSM 19286^T, displaying 99.1–99.3%, 99.2–99.6% and 99.4–100% sequence similarities, respectively, to these species. The results of DNA–DNA hybridization studies unambigiously indicated that the four strains belonged to the species L. capsici. Nevertheless, DNA fingerprinting and phenotypic characterization indicated that there was a considerable diversification and niche differentiation among the strains belonging to L. capsici. The newly identified L. capsici strains strongly inhibit Rhizoctonia solani AG2 and originate from Rhizoctonia-suppressive soils where also populations of L. antibioticus and L. gummosus were present. This is the first report of the presence of combined populations of closely related Lysobacter spp. within agricultural soils.     

Larval identification of Lutjanus Bloch in Nansha coral reefs by AFLP molecular method

Species of Lutjanus Bloch are highly valued fish in some fisheries of the world and some species are cultured in the Southeast Asia especially in South China. Wild larvae are still the major source of mariculture in South China because artificial breeding techniques for most Lutjanus species have not yet been available. The Nansha coral reefs (also called Spratly Archipelago) water area, which is located in the South China Sea, is the main habitat and spawn area for Lutjanus in China. Larval identification of Lutjanus is important for relative ecological studies and mariculture, but larvae of many closely related species, such as those of the genus Lutjanus, are different to be distinguished morphologically. In the present study, a PCR-based fingerprinting technique called amplified fragment length polymorphism AFLP was used in the characterization and identification of 11 Lutjanus species captured in Nansha coral reefs. Optimal AFLP patterns were obtained with primer combination of E+AGC/M+CAA selective nucleotides. There were in total 132 AFLP loci in all specimens, and AFLP markers of each species varied from 44 to 69, but only 7 markers were fixed in all specimens. Meanwhile, high levels of intraspecific homogeneity were observed. All 11 species of Lutjanus were successfully identified by the comparative analyses of AFLP patterns. Moreover, neighbour-joining and UPGMA analyses of AFLP data were compared with current morphological taxonomic systems.