Suppression subtractive hybridization cloning of cDNAs of differentially expressed genes in dovetree (<Emphasis Type="Italic">Davidia involucrata</Emphasis>) bracts

A subtracted cDNA library forDavidia involucrata was constructed using suppression subtractive hybridization (SSH). mRNA isolated from young leaves was used as a “driver,” and mRNAs isolated from young bracts were used as “testers.” The differentially expressed cDNA fragments in bracts were identified by differential screening. Of the 16 clones selected randomly from the screened library, 8 were known genes found in GenBank, and 2 had no similar sequences. Northern blot analysis revealed that the expression level of P1A5 cDNAs selected randomly was dominantly expressed in bracts. This indicates that SSH can be used to clone differentially expressed cDNAs inD. involucrata bracts.     

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.     

Taxonomic status of Cuscuta nevadensis and C. veatchii (Convolvulaceae) in North America

The taxonomy ofCuscuta nevadensis andC. veatchii is investigated.Cuscuta nevadensis is more closely related toC. veatchii andC. denticulata than toC. salina, and the former two taxa are accepted as species. A summary of relevant taxonomic and biological information is provided, including synonymy, distribution and ecology, keys, and a comparison of the morphology of flowers and seeds are examined. The morphological basis of vivipary inC. nevadensis is discussed. The status ofCuscuta vivipara, an invalid name in recent use, is clarified.     

Floral scent chemistry and pollination ecology in phytelephantoid palms (Arecaceae)

The subfamilyPhytelephantoideae comprises three genera (Ammandra, Aphandra, andPhytelephas) and seven species of dioecious palms. The floral scents ofAmmandra dasyneura, A. decasperma, Aphandra natalia, Phytelephas aequatorialis, P. macrocarpa, andP. seemannii were analyzed by gas chromatography-mass spectrometry. We studied the pollination biology ofA. natalia, P. aequatorialis, andP. macrocarpa, and tested how the synthetically produced main constituents of the floral scents ofAphandra andPhytelephas attracted insects in two natural populations ofPhytelephas. The genera are distinct in terms of floral scents.Ammandra has sesquiterpenes,Aphandra (+)-2-methoxy-3-sec-butylpyrazine, andPhytelephas p-methyl anisol. These constituents dominated the scents quantitatively and qualitatively. The similarity between scents of male and female inflorescences was 76.5% inAmmandra, 84.2% inAphandra, and >99% inPhytelephas. Different species ofAleocharinae (Staphylinidae) pollinateAphandra natalia andPhytelephas species and reproduce in their male inflorescences.Derelomini (Curculinoidae) andMystrops (Nitidulidae) only visit and pollinatePhytelephas in which male inflorescences they reproduce. A species ofBaridinae (Curculionidae) only visits and pollinatesAphandra natalia, and reproduces in its female inflorescence. The apparent reliance on one or a few floral scent constituents as attractants and few and specific pollinators may indicate co-evolution. Sympatric species ofPhytelephantoideae have different scents. We suggest that species with similar scents have allopatric distributions due to the absence of a pollinator isolation mechanism.     

Cloning and heterologous expression of nitrate reductase genes from <Emphasis Type="Italic">Dunaliella salina</Emphasis>

A cDNA corresponding to the nitrate reductase (NR) gene from Dunaliella salina was isolated by RT-PCR and (5′/3′)-RACE techniques. The full-length cDNA sequence of 3,694 bp contained an open reading frame of 2,703 bp encoding 900 amino acids, a 5′-untranslated region of 151 bp and a 3′-untranslated sequence of 840 bp with a poly (A) tail. The putative gene product exhibited 78%, 65%, 59% and 50% identity in amino acid sequence to the corresponding genes of Dunaliella tertiolecta, Volvox carteri, Chlamydomonas reinhardtii, and Chlorella vulgaris, respectively. Phylogenetic analysis showed that D. salina NR clusters together with known NR proteins of the green algae. The molecular mass of the encoded protein was predicted to be 99.5 kDa, with an isoelectric point of 8.31. This protein shares common structural features with NRs from higher plants and green algae. The full-length cDNA was heterologously expressed in Escherichia coli as a fusion protein, and accumulated to up to 21% of total bacteria protein. Recombinant NR protein was active in an enzyme assay, confirming that the cloned gene from D. salina is indeed NR.     

New records of the carabidicolous laboulbeniales (Ascomycetes) of Japan

Six carabidicolous species of Laboulbeniales are reported as new for the Japanese mycoflora. They areDixomyces stomonaxi, Laboulbenia picardii, L. tenera, L. slackensis, L. aristata andL. kwangjuensis. Two forms ofD. stomonaxi are distinguished, one form of which resemblesD. nigromarginatus. A remarkable ornamentation consisting of a coillike pattern occurs on the receptacle ofL. picardii. InL. tenera andL. slackensis, the outer appendage has somewhat constricted, blackened septa near the base.Laboulbenia aristata andL. kwangjuensis have spirally arranged outer wall cells. Antheridia were observed inL. tenera, L. slackensis, L. aristata andL. kwangjuensis.     

Some Entolomataceae (Agaricales) from Costa Rica

A preliminary account of Entolomataceae from Costa Rica is presented. Three new taxa are described, two inClitopilus, one inRhodocybe, and three new combinations are proposed inInocephalus. Five taxa ofClitopilus are reported for the first time from Costa Rica and a key to species is provided. Four species ofRhodocybe are discussed and a key to the six species known from Costa Rica is also provided.Alboleptonia earlei, Inocephalus murraii, Inocephalus quadratum, Rhodocybe incarnata andRhodocybe pseudonitellina are now known to occur in Costa Rica.     

The chloroplast genome arrangement ofLobelia thuliniana (Lobeliaceae): Expansion of the inverted repeat in an ancestor of theCampanulales

A clone-bank ofSac I restriction fragments was constructed from the chloroplast DNA (cpDNA) ofLobelia thuliniana E. B. Knox (Lobeliaceae). These cloned fragments and a set of 106 clones spanning the tobacco chloroplast genome were used as probes to determine the cpDNA restriction fragment arrangement forSac I and six other restriction enzymes (BamH I,EcoR V,Hind III,Nci I,Pst I, andXho I) and the chloroplast genome arrangement ofL. thuliniana relative to tobacco, which has been fully sequenced and is collinear with the hypothesized ancestral genome arrangement of angiosperms. The results confirm and refine our previous understanding of the chloroplast genome arrangement in the large single-copy region (LSC) and reveal (1) a roughly 11 kilobase (kb) expansion of the inverted repeat (IR) into the small single-copy region (SSC) and (2) apparent sequence divergence of the DNA segment inL. thuliniana that corresponds to ORF1901 in tobacco. The expansion of the IR into the SSC is present in all other examined members ofLobeliaceae, Cyphiaceae, andCampanulaceae, which indicates that the IR expansion was an early event in the cpDNA evolution of theCampanulales. The IR expansion into the SSC was not present inSphenoclea, which additionally supports exclusion of this genus from theCampanulaceae.     

Revision ofDoniophyton (Compositae, Barnadesioideae)

This revision describes, illustrates and documents morphological variation inDoniophyton (Compositae, Barnadesioideae), restricted to Argentina and Chile. Two species are recognized,D. anomalum andD. weddellii (sp. nova), possessing distinct morphological and chromosomal features, elevational tolerances, and nearly allopatric distributions.Doniophyton weddellii occurs primarily in central to northern Andean Chile and Argentina from 1900–4000 m a. s. l.;D. anomalum is found principally in centralwestern Argentina and south into Patagonia at 0–1800 m a. s. l. Close relationship exists withChuquiraga of subfam.Barnadesioideae. It is hypothesized thatDoniophyton evolved out ofChuquiraga in the high central Andes between Chile and Argentina. It is suggested thatD. weddellii differentiated first, correlating with an aneuploid chromosomal decrease from n = 27 (inChuquiraga) to n = 25. Further evolution and chromosomal decrease to n = 24 resulted inD. anomalum, with accompanying migration into southern Andes and Patagonia. Nomenclatural changes result from examination of protologues and type specimens:Doniophyton anomalum replaces the commonly used nameD. patagonicum, and a new species,D. weddellii, is described for the taxon masquerading under the routinely used superfluous nameD. andicola. This paper is dedicated with admiration and respect to emer. Univ.-Prof. DrFriedrich Ehrendorfer, one of the world's outstanding plant systematists, and a leading scientist and administrator of the Institute of Botany of the University of Vienna     

Heterostyly in species ofNarcissus (Amaryllidaceae) andHugonia (Linaceae) and other disputed cases

The hypothesis ofHenriques andFernandes that several Iberian species ofNarcissus (Amaryllidaceae) are tristylous is reconsidered. Contrary to the opinion ofBateman and most subsequent authors, we believe that the available evidence indicates that some populations ofN. triandrus andN. fernandesii, at least, are tristylous; other populations ofN. triandrus are distylous.Hugonia cf.penicillanthemum (Linaceae) from new Caledonia is distylous, but it remains possible that other species ofHugonia are tristylous. The disputed occurrence of heterostyly in S. African species ofBauhinia (Leguminosae),Cleome (Capparaceae) andAneilema (Commelinaceae), and inAgelaea (Connaraceae) is discussed.     

Molecular cloning, expression analysis and chromosomal mapping of salt-responsive cDNAs in rice ( Oryza sativa L.)

By using differential display PCR (DD-PCR) technique, two salt-inducible and one salt-repressed cDNA fragments were isolated from rice. The three cDNA fragments were characterized respectively as partial sequence of rice S-adenosylmethionine decarboxylase (SAMDC) gene, a new member of translation elongation factor 1A gene (namedREF1 A), and a novel gene whose function is unknown (namedSRG1). The full-length cDNA of SAMDC gene (namedSAMDC1) was further isolated by RT-PCR approach and the deduced polypeptide was found to be homologous to SAMDC proteins of other plants, yeast and buman. Northern hybridization revealed that expression of SAMDCl and REFlA was induced, while SRGl was dramatically repressed, by salinity stress. Southern blot analysis demonstrated that SAMDCl and SRGl were present as a single copy gene in rice genome, whereas riceREF1 A gene was organized as a gene family. TheREF1 A,SAMDC1, andSRG1 genes were located on chromosome 3,4, and 6 respectively by RFLP mapping approach using ZYQ8/JX17 DH population and RFLP linkage maps. Project supported by the National “863” High-Technology Program.     

Expression of starvation-induced genes in zygotes ofDictyostelium discoideum

Two cDNA fragments induced in developing zygotes ofDictyostelium discoideum were isolated by mRNA differential display. the relevant genes were also found to be expressed during asexual development, suggesting that sexual and asexual development share common molecular mechanisms inD. discoideum.     

DNA evidence for multiple origins of intergeneric allopolyploids in annualMicroseris (Asteraceae)

Seventy populations of North American annualMicroseris, Stebbinsoseris, andUropappus species were examined for chloroplast and nuclear ribosomal DNA restriction site variability to determine the origin of the allotetraploid speciesS. heterocarpa andS. decipiens. Previously identified chloroplast DNA restriction site variants were used in concert with restriction site variation forNco I in the nuclear-encoded ribosomal DNA repeat. The presence of two, mutually exclusive restriction site gains were observed in diploid populations ofM. douglasii; these same variants were also found in populations of allotetraploidS. heterocarpa, indicating mutiple origins of this species from different maternal diploid populations ofM. douglasii. Variation in the rDNA repeat between the diploid annual species and the putative paternal genome ofU. lindleyi was found to be additive inS. heterocarpa. A similar relationship was observed for the origin ofS. decipiens; cpDNA restriction site variants found inM. bigelovii andM. douglasii were present inS. decipiens. The rDNANco I variants also were additive in this purported allotetraploid. These results confirm the reticulate evolutionary pattern inStebbinsoseris and provide another example of multiple origins of intergeneric allopolyploids.     

Distribution of similar self-incompatibility (<Emphasis Type="Italic">S</Emphasis>) haplotypes in different genera,<Emphasis Type="Italic"> Raphanus</Emphasis> and<Emphasis Type="Italic"> Brassica</Emphasis>

The nucleotide sequences of ten SP11 and nine SRK alleles in Raphanus sativus were determined, and deduced amino acid sequences were compared with those of Brassica SP11 and SRK. The amino acid sequence identity of class-I SP11s in R. sativus was about 30% on average, the highest being 52.2%, while that of the S domain of class-I SRK was 77.0% on average and ranged from 70.8% to 83.9%. These values were comparable to those of SP11 and SRK in Brassica oleracea and B. rapa. SP11 of R. sativus S-21 was found to be highly similar to SP11 of B. rapa S-9 (89.5% amino acid identity), and SRK of R. sativus S-21 was similar to SRK of B. rapa S-9 (91.0%). SP11 and SRK of R. sativus S-19 were also similar to SP11 and SRK of B. oleracea S-20, respectively. These similarities of both SP11 and SRK alleles between R. sativus and Brassica suggest that these S haplotype pairs originated from the same ancestral S haplotypes.     

Alkaloids of theSedum acre-group (Crassulaceae)

The 16 species of theSedum acre-group were investigated for the presence of alkaloids. They areS. acre ofS. ser.Acria, S. alpestre, S. annuum, S. apoleipon, S. borissovae, S. euxinum, S. grisebachii, S. laconicum, S. multiceps, S. sexangulare, S. tuberiferum, S. tuberosum, S. ursi, andS. urvillei ofS. ser.Alpestria, S. samium ofS. ser.Samia, andS. litoreum ofS. ser.Litorea. S. acre differs significantly from the other species. It contains sedamine, hydroxy sedamine, and a number of 2,6-disubstituted piperidine alkaloids. The leafy parts of the species ofS. ser.Alpestria, S. ser.Samia, andS. ser.Litorea contain 4 piperidine alkaloids which also occur inS. acre, and in addition 4 pyrrolidine alkaloids not present inS. acre. The composition of the alkaloid fraction agrees with the infrageneric classification (series) based on the hybridization patterns of the species (comparia).     

Relationships between species ofLeymus,Psathyrostachys, andHordeum (Poaceae,Triticeae) inferred from Southern hybridization of genomic and cloned DNA probes

We have used total genomic DNA as a probe to size-fractionated restriction enzyme digests of genomic DNA from a range ofTriticeae species from the generaLeymus Hochst.,Psathyrostachys Nevski, andHordeum L., and hybrids betweenHordeum andLeymus to investigate their taxonomic relationships. Genomic Southern hybridization was found to be an effective and simple way to assess the distribution and diversity of essentially species-specific and common, repetitive DNA sequences, and is hence especially useful in evolutionary studies. The DNA sequences ofH. vulgare seem to diverge substantially from those ofH. brachyantherum, H. lechleri, H. procerum, andH. depressum. The genome ofThinopyron bessarabicum shows little homology to those of theLeymus species investigated, confirming thatT. bessarabicum is not an ancestral genome inLeymus. Although the genomes ofLeymus andPsathyrostachys share substantial proportions of DNA sequences, they include divergent repeated sequences as well. Hybridization with a ribosomal DNA probe (pTa 71) showed that the coding regions containing structural genes encoding the 18 S, 5.8 S, and 26 S ribosomal RNA were conserved among the species investigated, whereas the intergenic spacer region was more variable, presenting different sizes of restriction fragments and enabling a classification of the species. The rye heterochromatin probe pSc 119.2 hybridized to DNA fromH. lechleri andT. bessarabicum, but not to DNA from the other species investigated.     

Electrophoretic variation of the apogamousDryopteris varia group (Dryopteridaceae)

A total of 35 electrophoretic variants were detected in four apogamous species of theDryopteris varia group: 14 variants inD. bissetiana triploids, 7 inD. sacrosancta triploids, 6 inD. varia triploids, 3 inD. pacifica triploids, and 5 in apogamous diploids. The variants differed from each other in various combinations of a few alleles which were common in some of the variants, suggesting recurrent origin.Dryopteris insularis var.insularis (2x) and var.chichisimensis (3x), other members of the group, were electrophoretically monomorphic, suggesting single origin. Banding patterns infer that triploids ofD. bissetiana andD. sacrosancta may have originated from hybrids whose parent is the sexualD. saxifraga, whereas this species was not involved in the origin of the other apogamous triploids and the apogamous diploids. The other parent was also discussed and we proposed a hypothesis that diploid offsprings fromD. pacifica triploids hybridized withD. saxifraga giving rise to triploids ofD. bissetiana andD. sacrosancta.     

Nucleotide distribution in bacterial DNA's differing in G + C content

Summary The DNA's ofMicrococcus lysodeikticus andClostridium perfringens were fragmented to about 7 000 nucleotide pairs long by shear and fractionated with respect to buoyant density of mercury complexes in Cs₂SO₄. The distribution of G + C content in both DNA's was characteristically asymmetric. InM. lysodeikticus DNA, low G + C fragments were more numerous than high G + C fragments, whereas inC. perfringens DNA, high G + C fragments were more numerous than low G + C fragments. The G + C content of fragments ofM. lysodeikticus DNA varied from 70 to 77%, with a mean and standard deviation of 73.7 ± 1.92% G + C and that ofC. perfringens DNA varied from 27 to 34%, with a mean and standard deviation of 29.8 ± 1.34% G + C. The standard deviation was smaller than that ofEscherichia coli DNA fragments of similar size. Biological meanings of relatively low heterogeneity in nucleotide composition inM. lysodeikticus andC. perfringens are discussed.