Molecular cytogenetic evidence of hybridization in the “purple corolla clade of the genus Capsicum” (C. eximium × C. cardenasii)

Abstract

A hybrid individual between two taxa from “the Purple Corolla clade of the genus Capsicum”, C. eximium × C. cardenasii (2n = 24) was found during a cytogenetic study of a population belonging to C. cardenasii cytotype 1, from Bolivia. 5S and 45S rDNA probes were located on mitotic chromosomes by fluorescent in situ hybridization. The hybrid haploid karyotype length was an average value of the two taxa; the hybrid presented 24 45S loci in the diploid complement, 18 45S sites belonged to C. cardenasii cytotype 2, and six came from C. eximium cytotype 2, although this cytotype of C. eximium has been mentioned only for Argentina. Whereas hybrids were previously reported in the purple flower group, their existence has not been cytologically corroborated. This finding constitutes the first molecular cytogenetic evidence of hybridization between two taxa from this group.     

COLEOFASCICULUS GEN. NOV. (CYANOBACTERIA): MORPHOLOGICAL AND MOLECULAR CRITERIA FOR REVISION OF THE GENUS MICROCOLEUS GOMONT1

Species currently classified within the cyanobacterial genus Microcoleus were determined to fall into two distinct clades in a 16S rDNA phylogeny, one containing taxa within the Oscillatoriaceae, the other containing taxa within the Phormidiaceae. The two lineages were confirmed in an analysis of the 16S–23S internal transcribed spacer (ITS) region sequences and secondary structures. The type species for Microcoleus is M. vaginatus Gomont, and this taxon belongs in the Oscillatoriaceae. Consequently, Microcoleus taxa in the Phormidiaceae must be placed in separate genera, and we propose the new genus Coleofasciculus to contain marine taxa currently placed in Microcoleus. The type species for Coleofasciculus is the well‐studied and widespread marine mat‐forming species Microcoleus chthonoplastes (Mert.) Zanardini ex Gomont. Other characters separating the two families include type of cell division and thylakoid structure.     

BRASILONEMA ANGUSTATUM SP. NOV. (NOSTOCALES), A NEW FILAMENTOUS CYANOBACTERIAL SPECIES FROM THE HAWAIIAN ISLANDS1

A new filamentous cyanobacterial species of the genus Brasilonema was isolated from the island of Oahu, Hawaii. The taxon is distinguished from the seven other species in the genus by attenuation of trichomes, and is here described as Brasilonema angustatum sp. nov. It possesses the cytoplasmic kerotimization and reddish‐brown coloration of several species in the genus. Phylogenetic analysis based on 16S rRNA gene sequence shows B. angustatum within a highly supported clade containing all sequenced Brasilonema species. We compared the secondary structure of the 16S–23S ITS regions for B. octagenarum and B. angustatum. The structurally conservative D1–D1′ and V3 helices show similar motifs between the two taxa, but differ structurally and in sequence, providing additional justification for erection of the new species. The Box‐B helix has identical secondary structure. The existence of tapering in a Brasilonema species is unique in this genus, and requires modification of the current concept of the genus Brasilonema, which was described as being unattenuated. Our phylogenetic evidence supports the hypothesis that tapering has developed repeatedly in separate cyanobacterial lineages and lacks the taxonomic significance once assumed by early workers.     

New Systematic Insights in the Ceramium Sinicolacomplex: Resurrection of C. Interruptum S. & G. (Ceramiaceae,Rhodophyta)

Setchell & Gardner (1924) provided a taxonomic treatment for the genus Ceramium from lower California and the Gulf of California, Mexico, in which they described several new species, including C. sinicola S. & G. described from Ensenada, BCN and C. interruptum S. & G. described from the vicinity of La Paz, BCS. The latter was later reduced to variety rank in C. sinicolaby Dawson (1950), a taxonomic decision that has subsequently been widely adopted. Phylogenetic analyses inferred from three molecular markers (chloroplast‐encoded rbcL, the RUBISCO spacer, and nuclear encoded SSU rDNA) from recent collections from the Pacific North‐west (California, Oregon) and the Gulf of California reveal a well supported assemblage of three corticated taxa: C. codicolaJ. Ag. 1894, C. sinicola and C. sinicola var. interruptum. Sequence divergence values among the three taxa are sufficient to warrant separate species ranking; hence, we reinstate C. interruptum as a widely distributed epiphyte for the region. C. sinicolais more closely related to C. codicolathan to C. interruptum, with the former two restricted to the host Codium. The molecule‐based relationships are congruent with evolutionary trends in cortication pattern and attachment mode.     

Igniting taxonomic curiosity: The amazing story of Amazonocrinis with the description of a new genus Ahomia gen. nov. and novel species of Ahomia,Amazonocrinis, and Dendronalium from the biodiversity-rich northeast region of India

Five cyanobacterial strains exhibiting Nostoc-like morphology were sampled from the biodiversity hotspots of the northeast region of India and characterized using a polyphasic approach. Molecular and phylogenetic analysis using the 16S rRNA gene indicated that the strains belonged to the genera Amazonocrinis and Dendronalium. In the present investigation, the 16S rRNA gene phylogeny clearly demarcated two separate clades of Amazonocrinis. The strain MEG8-PS clustered along with Amazonocrinis nigriterrae CENA67, which is the type strain of the genus. The other three strains ASM11-PS, RAN-4C-PS, and NP-KLS-5A-PS clustered in a different clade that was phylogenetically distinct from the Amazonocrinis sensu stricto clade. Interestingly, while the 16S rRNA gene phylogeny exhibited two separate clusters, the 16S–23S ITS region analysis did not provide strong support for the phylogenetic observation. Subsequent analyses raised questions regarding the resolving power of the 16S–23S ITS region at the genera level and the associated complexities in cyanobacterial taxonomy. Through this study, we describe a novel genus Ahomia to accommodate the members clustering outside the Amazonocrinis sensu stricto clade. In addition, we describe five novel species, Ahomia kamrupensis, Ahomia purpurea, Ahomia soli, Amazonocrinis meghalayensis, and Dendronalium spirale, in accordance with the International Code of Nomenclature for algae, fungi, and plants (ICN). Apart from further enriching the genera Amazonocrinis and Dendronalium, the current study helps to resolve the taxonomic complexities revolving around the genus Amazonocrinis and aims to attract researchers to the continued exploration of the tropical and subtropical cyanobacteria for interesting taxa and lineages.     

Correlations between genet architecture and some life history features in three species of Solidago

Summary Members of the genus Solidago are among the most widely studied model systems in plant population biology. A comparative study of Solidago canadensis, S. altissima, and S. gigantea in an experimental garden showed that the three species had different patterns of shoot growth and development, leaf morphology and physiology, and biomass allocation at harvest. These differences were also found in the field. Contrary to some current taxonomic usage, our results show that S. canadensis should ecologically be treated as a separate taxon distinct from S. altissima, and that the latter may be grouped together with S. gigantea. Many of the biological differences between S. canadensis and the other two taxa, such as differential investment into sexual reproduction versus clonal growth, may be explained by differences in genet architecture. These architectures concern high compared to lower within-genet shoot density resulting from differences in rhizome lengths among the taxa (shorter in S. canadensis than in S. altissima and S. gigantea).     

Phylogeny and biogeography of the lamioid genus <Emphasis Type="Italic">Phlomis</Emphasis> (Lamiaceae)

The genus Phlomis is one of the largest genera of subfamily Lamioideae (Lamiaceae) with more than 100 recognised species distributed in Asia, southern Europe and northern Africa. Morphological studies have suggested that the species can be split into two morphologically distinct groups that have previously been recognised as either sections or separate genera. The current study represents the first molecular phylogenetic study of the genus in which taxa representative of the entire genus are included. In contrast to considerable morphological and ecological variation among taxa, sequence variation in the trnL intron, the trnL – F intergenic spacer, and the rps16 intron was low, resulting in sparse phylogenetic resolution, particularly among the South West Asian and Mediterranean taxa. However, the results support a split of the genus into two separate groups that are recognised here as the genera Phlomoides and Phlomis in order to decrease taxonomic complexity. The close relationship between Phlomis s.l. and Eremostachys, pointed out by several authors, is confirmed, and in a noteworthy new finding, the small Asian genus Notochaete, is more closely related to the Phlomis s.l. lineage than previously assumed. The two monotypic genera Pseuderemostachys and Lamiophlomis as well as Notochaete hamosa are transferred to Phlomoides and three new combinations are made. Character optimisation analyses based on geographic distributions of all taxa show that the groups obtained by molecular phylogenetic analysis correlate well with biogeography. The results suggest that the Phlomis s.l. lineage has a Central Asian origin in an area around Western China.     

Contribution to the taxonomy and phylogeny of Sarcocapnos DC. (Fumariaceae)

 To solve problems concerning the status of the taxa described in the genus Sarcocapnos, we have conducted a study using morphological, pollen morphology (light microscopy), cytogenetic and molecular techniques. Focusing on the last technique, we have sequenced ITS-1 and ITS-2 of nuclear rDNA. The species differ basically according to 5 morphological traits (leaf shape, flower spur, corolla colour, corolla size, and crest of the stigmatic surface). The cytogenetic analyses indicated n=16 to be the standard chromosome number. The ITS analyses showed that the genus is monophyletic, defining two main well-supported clades, one containing S. saetabensis and S. enneaphylla, and one containing the rest of the species. In this second clade, S. speciosa, S. pulcherrima, and S. baetica subsp. ardalii are related, as are S. integrifolia, S. crassifolia subsp. crassifolia, and S. crassifolia subsp. atlantis; S. baetica subsp. baetica forms a trichotomy with the foregoing groups. S. speciosa is shown to be a species separate from S. crassifolia subsp. crassifolia, as in the case of S. baetica with respect to S. integrifolia. Palynologically, the parameters used enabled us to establish clear differences between the taxa, often corroborating the macromorphological and genetic data. The flower spur has been reduced several times in different groups of the genus, for which the classifications established on the basis of this trait are paraphyletic. Received July 16, 2002; accepted December 11, 2002 Published online: March 31, 2003     

A study of Sarcocornia A.J. Scott (Chenopodiaceae) from Western Mediterranean Europe

The latest publications on Sarcocornia taxonomy and phylogeny recognize six taxa in this genus on the Iberian Peninsula: S. perennis, S. fruticosa, S. alpini, S. alpini subsp. carinata, S. hispanica, and S. pruinosa. The present study represents a comprehensive revision of the different taxa in the Sarcocornia genus present in Western Mediterranean Europe by means of morphological, micromorphological and phylogenetic internal transcribed spacer (ITS) analysis. Morphological and micromorphological data were studied from Sarcocornia samples from 113 populations in coastal salt marshes and inland salt pans in Portugal, France, Spain and Italy. Sixteen new ITS sequences were obtained from Mediterranean Sarcocornia species and analysed together with previous reported data. Published karyological, ecological and biogeographical data from Western Mediterranean Europe were also reviewed. The results indicate the presence of a new species, S. lagascae, found growing in coastal Mediterranean areas of the Iberian Peninsula. The species S. fruticosa was found to be absent from the Iberian territories.     

Three new species of <Emphasis Type="Italic">Stelis</Emphasis> (Orchidaceae) from Mexico

Three new species of the genus Stelis from Mexico are described and illustrated; they were recently collected in the Tacana volcano region of Chiapas, and are named as S. annedamoniae, S. hagsateri, and S. soconuscana. For each species information is provided about habitat, phenology, and conservation status, and the relationships with similar taxa are discussed. Stelis andamoniae is similar to S. hagsateri and both are sympatric at the Tacana volcano; they are members of the Stelis argentata complex. The first has red-wine flowers, and glabrous sepals, while S. hagsateri has greenish-yellow flowers and glandular-papillose sepals. Stelis soconuscana is similar to S. bidentata, from which it is different by its broader leaves, raceme as long as the leaf, smaller flowers, and its distribution.     

Molecular phylogeny and taxonomy of the genus Chaetophora (Chlorophyceae,Chlorophyta), including descriptions of Chaetophoropsis aershanensis gen. et sp. nov.

The broadly defined genus Chaetophora consisted of species with minute, uniseriate branching filaments enveloped in soft or firm mucilage forming macroscopic growths that are spherical, hemispherical, and tubercular or arbuscular, growing epiphytically on freshwater aquatic plants and other submerged surfaces in standing or fast‐flowing water. Recent molecular analyses clearly showed that this genus was polyphyletic. In this study, eight strains of Chaetophora and three strains of Stigeoclonium were identified and successfully cultured. In combination with the morphological data, a concatenated data set of four markers (18S + 5.8S + ITS2+ partial 28S rDNA) was also used to determine their taxonomic relationships and phylogenetic positions. The molecular analysis resolved the broadly defined Chaetophora to at least two genera. Species with a globose thallus of genus Chaetophora formed a separate monophyletic clade, which clearly separated from, a type of lobe‐form Chaetophora species. Therefore, we propose to erect a new genus, Chaetophoropsis, which includes all globose species of the Chaetophora. Chaetophoropsis aershanensis was determined to be a new species, based on its special characteristic of profuse long rhizoids. Stigeoclonium polyrhizum, as the closest relative to Chaetophoropsis, revealed its distant relationships to other species of Stigeoclonium. A globose thallus with a thick, soft mucilage matrix, and special rhizoidal branches lent further support to the placement of S. polyrhizum in the genus Chaetophoropsis and had the closest relationship to C. aershanensis. Taxonomic diversity was proven by distinctive morphological differences and by phylogenetic divergence in the broadly defined Chaetophora identified herein.     

Hybridisation,genomic constitution and generic delimitation inElymus s. l. (Poaceae: Triticeae)

Intergeneric crosses were made between representatives of the genomically-defined generaElymus, Agropyron, Elytrigia, Pseudoroegneria, andThinopyrum. The genomic constitution ofElytrigia repens, the type species ofElytrigia, is shown to be SSH, a genomic combination otherwise found only inElymus. The S genome ofPseudoroegneria has almost always a dominant influence on the morphology of the taxa of which it is a component.Wang (1989) showed that the J genome inThinopyrum and the S genome have considerable homoeology, with a mean c-value of 0.35 in diploid SJ hybrids. A genetic coherence from S to SJ^e, J^e, J^eJ^b, and J^b can be expected, agreeing with the continuous morphologic variation pattern observed. Because of the absence of morphological discontinuities between the taxa,Pseudoroegneria (S),Elymus (SH, SY, sometimes with additional genomes),Elytrigia (SSH, SSHX), andThinopyrum (SJ, SJJ, J) are best treated as a single genus,Elymus, following the generic concept ofMelderis in Flora Europaea and Flora of Turkey. The basic genomic constituents ofElymus will then be the S and/or J genomes.Agropyron, with diploids, tetraploids, and hexaploids based on the P genome is morphologically distinct from other genera inTriticeae. In a few species ofElymus andPseudoroegneria, a P genome is an additional constituent. In these cases the P genome has a negligible morphological influence. Therefore, it seems reasonable to maintainAgropyron as a separate genus.     

Two new species of Phyllonema (Rivulariaceae,Cyanobacteria) with an emendation of the genus

Two untapered, heterocytous species were observed and collected from the intertidal and supratidal zones of the Mexican coastline of the Pacific Ocean near Oaxaca and from the Gulf of Mexico. These populations were highly similar in morphology to the freshwater taxon Petalonema incrustans in the Scytonemataceae. However, 16S rRNA sequence data and phylogenetic analysis indicated that they were sister taxa to the epiphyllic, Brazilian species Phyllonema aveceniicola in the Rivulariaceae, described from culture material. While genetic identity between the two new species was high, they differed significantly in morphology, 16S rRNA gene sequence identity, and sequence and structure of the 16S–23S ITS region. Their morphology differed markedly from the generitype of the previously monotypic Phyllonema, which has tapered, heteropolar, single‐false branched trichomes with very thin or absent sheath. The two new species, Phyllonema ansata and Phyllonema tangolundensis, described from both culture and environmental material, have untapered, isopolar, geminately false branched trichomes with thick, lamellated sheaths, differences so significant that the species would not be placed in Phyllonema without molecular corroboration. The morphological differences are so significant that a formal emendation of the genus is required. These taxa provide a challenge to algal taxonomy because the morphological differences are such that one would logically conclude that they represent different genera, but the phylogenetic evidence for including them all in the same genus is conclusive. This conclusion is counter to the current trend in algal taxonomy in which taxa with minor morphological differences have been repeatedly placed in separate genera based primarily upon DNA sequence evidence.     

Phylogeny of Oedogoniales (Chlorophyceae, Chlorophyta) inferred from 18S rDNA sequences with emphasis on the relationships in the genus Oedogonium based on ITS-2 sequences

The phylogeny of Oedogoniales was investigated by using nuclear 18S rDNA sequences. Results showed that the genus Oedocladium, as a separated clade, was clustered within the clade of Oedogonium; whereas the genus Bulbochaete was in a comparatively divergent position to the other two genera. The relationship among the species of Oedogonium was discussed, focusing on ITS-2 phylogeny analyzed combining with some morphological characteristics. Our results showed that all the dioecious nannandrous taxa involved in this study were resolved into one clade, while all the monocious taxa were clustered into another clade as a sister group to the former. The report also suggests that the dioecious macrandrous taxa form a paraphyly and could be more basally situated than the dioecious nannandrous and the monoecious taxa by means of molecular phylogeny and morphotype investigations.     

Evolutionary relationships of endemic Draparnaldioides simplex C. Meyer et Skabitch. Green alga from Lake Baikal with non-Baikalian taxa of chaetophoraceae (Chlorophyta) family

The phylogenetic relationships between Baikalian endemic green alga Draparnaldioides simplex C. Meyer et Skabitch., 1976 and holarctic taxa of green algae have been studied using the 18S rDNA gene fragment and internal transcribed ITS1 and ITS2 spacers of nuclear DNA. The Baikalian genus Draparnaldioides was shown to be a separate taxon. The level of genetic difference between the studied species and non-Baikalian taxa of sister groups of green algae is insignificant, which indicates the young age of the genus Draparnaldioides and its recent radiation from the common ancestor with genera Draparnaldia and Chaetophora.     

Comparing Morphological and Molecular Estimates of Species Diversity in the Freshwater Genus Synura (Stramenopiles): A Model for Understanding Diversity of Eukaryotic Microorganisms

We performed a comparison of molecular and morphological diversity in a freshwater colonial genus Synura (Chrysophyceae, Stramenopiles), using the island of Newfoundland (Canada) as a case study. We examined the morphological species diversity in collections from 79 localities, and compared these findings to diversity based on molecular characters for 150 strains isolated from the same sites. Of 27 species or species-level lineages identified, only one third was recorded by both molecular and morphological techniques, showing both approaches are complementary in estimating species diversity within this genus. Eight taxa, each representing young evolutionary lineages, were recovered only by sequencing of isolated colonies, whereas ten species were recovered only microscopically. Our complex investigation, involving both morphological and molecular examinations, indicates that our knowledge of Synura diversity is still poor, limited only to a few well-studied areas. We revealed considerable cryptic diversity within the core S. petersenii and S. leptorrhabda lineages. We further resolved the phylogenetic position of two previously described taxa, S. kristiansenii and S. petersenii f. praefracta, propose species-level status for S. petersenii f. praefracta, and describe three new species, S. vinlandica, S. fluviatilis, and S. cornuta. Our findings add to the growing body of literature detailing distribution patterns observed in the genus, ranging from cosmopolitan species, to highly restricted taxa, to species such as S. hibernica found along coastal regions on multiple continents. Finally, our study illustrates the usefulness of combining detailed morphological information with gene sequence data to examine species diversity within chrysophyte algae.     

A molecular phylogeny of East African Amytta (Orthoptera: Tettigoniidae,Meconematinae) with data on their cytogenetics

This is the first study to address the molecular phylogeny of East African Meconematinae. We used DNA sequence data from the three genes cytochrome oxidase subunit I (COI ), 16S rRNA and histone H3 to reconstruct the relationships within the genus Amytta using Bayesian Inference and maximum likelihood. We included 45 individuals representing 19 Meconematinae taxa from Africa, Europe and Australia, and three outgroup species to explore taxonomic limits at different levels. Members of the genus Amytta belong to three related lineages within Meconematinae. Species of Amytta were found to be monophyletic with Meconema and Phlugidia as sister groups. The molecular results are in accordance with previous morphological and ecological studies. Chromosome numbers and the type of sex determination systems found in Amytta agrees with the three lineages also found in the phylogenetic tree. We conclude that the radiation of Amytta species is geological young. Biogeographical patterns caused by climatic fluctuations of the past seen also in other nonrelated Orthoptera taxa such as the coptacrine genus Parepistaurus are the drivers of biodiversity in the area.     

A molecular phylogeny of the genus Apis suggests that the Giant Honey Bee of the Philippines,A. breviligula Maa,and the Plains Honey Bee of southern India,A. indica Fabricius,are valid species

Two new taxa have been added to the existing molecular phylogenies of the genus Apis. The new phylogeny supports the accepted phylogenetic relationships of {dwarf honey bees [giant honey bees (cavity‐nesting honey bees)]}. Based on Bayesian and maximum parsimony trees, our analysis supports recognition of Apis indica, the Plains Honey Bee of south India, as a separate species from A. cerana. Our analysis also supports recognition of the Giant Philippines Honey Bee, A. breviligula, as a separate species from A. dorsata.     

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.