Genetic variation within and among small isolated populations of <Emphasis Type="Italic">Santalum album</Emphasis>

A combination of directed amplification of minisatellite DNA (DAMD) and random amplification of polymorphic DNA (RAPD) primes were used to assess the genetic variation within and between three isolated populations of Indian sandalwood (Santalum album). Eleven primers used in this study amplified 65.99 % polymorphic bands. Analysis of molecular variance revealed a high genetic variation among these populations (ϕ_ST = 0.549). There are indications of clonality within the existing Indian sandalwood populations which can be attributed to habitat fragmentation, isolation and vegetative reproduction.     

Genetic structure of Schrenck newt <Emphasis Type="Italic">Salamandrella schrenckii</Emphasis> populations by mitochondrial cytochrome <Emphasis Type="Italic">b</Emphasis> variation

The nucleotide sequence variation of the mitochondrial cytochrome b gene was studied in Schrenck newt Salamandrella schrenckii (Strauch, 1870) from populations of Primorye and the Khabarovsk region. Phylogenetic analysis revealed two haplotype clusters, southern cluster 1 and northern cluster 2, with a divergence of 3%. Analysis of the mtDNA and cytochrome b amino acid sequence variations made it possible to assume that the modern range of Schrenck newt was colonized from south Primorye northwards. In contrast to the southern cluster, the northern one demonstrated all the signs of demographic expansion (a unimodal distribution of pairwise nucleotide differences, specific results of tests for selective neutrality of mtDNA variation, and a good correspondence of genetic parameters to those expected from demographic expansion models).     

<Emphasis Type="Italic">Ty</Emphasis>1<Emphasis Type="Italic">/copia</Emphasis>- and <Emphasis Type="Italic">Ty</Emphasis>3<Emphasis Type="Italic">/gypsy</Emphasis>-like DNA sequences in <Emphasis Type="Italic">Helianthus </Emphasis>species

Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.     

<Emphasis Type="Italic">Agrobacterium</Emphasis><Emphasis Type="Italic">tumefaciens</Emphasis>-mediated transformation of callus cells of <Emphasis Type="Italic">Crataegus</Emphasis><Emphasis Type="Italic">aronia</Emphasis>

A genetic transformation system has been developed for callus cells of Crataegus aronia using Agrobacterium tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with 5 mg l⁻¹ Indole-3-butyric acid (IBA) and 0.5 mg l⁻¹ 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red colored callus was obtained on MS medium supplemented with 2 mg l⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l⁻¹ kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l⁻¹ hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this is the first time to report an Agrobacterium-mediated transformation system in Crataegus aronia.     

<Emphasis Type="Italic">Galleria</Emphasis><Emphasis Type="Italic">mellonella</Emphasis> are Resistant to <Emphasis Type="Italic">Pneumocystis</Emphasis><Emphasis Type="Italic">murina</Emphasis> Infection

Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner. The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate larvae Galleria mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host.     

Revision of the <Emphasis Type="Italic">Serrulati</Emphasis> species of <Emphasis Type="Italic">Penstemon</Emphasis> section <Emphasis Type="Italic">Saccanthera</Emphasis> subsection <Emphasis Type="Italic">Serrulati</Emphasis>

A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations.     

The <Emphasis Type="Italic">Caenorhabditis</Emphasis><Emphasis Type="Italic">briggsae</Emphasis> genome contains active <Emphasis Type="Italic">CbmaT1</Emphasis> and <Emphasis Type="Italic">Tcb1</Emphasis> transposons

The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.     

Unique pattern of <Emphasis Type="Italic">R-</Emphasis>gene variation within populations in Arabidopsis

An understanding of the variation pattern in disease resistance (R) genes is essential for its use in breeding programs aimed at neutralizing the threat of pathogens. Although the variation between populations is well known, there is little research about R-gene variation patterns within populations. Here, we investigate the polymorphism at three R-gene loci of 39 individual plants from nine populations of Arabidopsis thaliana. Our data suggest that alleles of each locus from individuals within a local population were either nearly identical, or highly diverse as ones between populations. The vast majority (92.5%) of within-population variation was shared globally, with high levels of allelic diversity (up to 11.7%) and abundant diverse-alleles. This unique pattern of within-population variation at R-loci suggests that individual plants within a population had the great potential to maintain a high level of globally-shared polymorphisms, and that the diversifying selection was the major force maintaining such polymorphisms. Consequently, the shared-polymorphism became recyclable for new R-genes, as the corresponding avirulence re-emerges in pathogen populations. Nucleotide sequence data reported are available in the GenBank databases under the accession numbers EF368054-EF368158.     

In planta transformation of <Emphasis Type="Italic">Notocactus scopa</Emphasis> cv. <Emphasis Type="Italic">Soonjung</Emphasis> by <Emphasis Type="Italic">Agrobacterium </Emphasis><Emphasis Type="Italic">tumefaciens</Emphasis>

Notocactus scopa cv. Soonjung was subjected to in planta Agrobacterium tumefaciens-mediated transformation with vacuum infiltration, pin-pricking, and a combination of the two methods. The pin-pricking combined with vacuum infiltration (20-30 cmHg for 15 min) resulted in a transformation efficiency of 67-100%, and the expression of the uidA and nptII genes was detected in transformed cactus. The established in planta transformation technique generated a transgenic cactus with higher transformation efficiency, shortened selection process, and stable gene expression via asexual reproduction. All of the results showed that the in planta transformation method utilized in the current study provided an efficient and time-saving procedure for the delivery of genes into the cactus genome, and that this technique can be applied to other asexually reproducing succulent plant species.     

The <Emphasis Type="Italic">Adh</Emphasis> locus and adaptation of <Emphasis Type="Italic">cn</Emphasis> and <Emphasis Type="Italic">vg</Emphasis> mutants in experimental populations of <Emphasis Type="Italic">Drosophila melanogaster MEIG</Emphasis>

A complex study on the adaptation of cn and vn mutants and the allozymes of alcoholdehydrogenase (ADH) was carried out in initially pure lines, and their panmixia populations during exchange of the mutant genotype with that of wild-type flies (C-S) and D) through saturating crossings. The relative adaptation of the genotypes was estimated by their effect on reproductive efficiency in the experimentally obtained population. Fecundity, lifespan, and the resistance of the studied genotypes to hyperthermia were investigated individually. It was shown that the high level of adaptation of the cn mutants and the low level of adaptation of the vg mutants was correlated with the presence of different ADH allozymes. In the studied population, the F-allozyme of ADH accompanied the vg mutation, while the S-allozyme of the enzyme was detected in cn mutants. Saturating crossings of C-S(Adh ^S)×vg(Adh ^F) and D(Adh ^F) × cn(Adh ^S), along with the parallel determination of the allele composition of the Adh locus, demonstrated that the complete substitution of the F-allozyme of ADH in the vg mutants by the S-allozyme in D flies, as well as the substitution of the S-allozyme of ADH in the cn mutants by the F-allozyme in D flies was realized only after the 15th–20th backcrosses. These results favor the coadaptation of cn and vg marker genes with alleles of the Adh locus and indicate the important role of the latter in the adaptation of genotypes. In the studied population, selection acted primarily against the vg mutants, which were inferior to the cn mutants, and heterozygote genotypes in indices of the main adaptation components.     

Genetic mapping of stem rust resistance gene <Emphasis Type="Italic">Sr13</Emphasis> in tetraploid wheat (<Emphasis Type="Italic">Triticum turgidum</Emphasis> ssp. <Emphasis Type="Italic">durum</Emphasis> L.)

Wheat stem rust caused by Puccinia graminis f. sp. tritici, can cause significant yield losses. To combat the disease, breeders have deployed resistance genes both individually and in combinations to increase resistance durability. A new race, TTKSK (Ug99), identified in Uganda in 1999 is virulent on most of the resistance genes currently deployed, and is rapidly spreading to other regions of the world. It is therefore important to identify, map, and deploy resistance genes that are still effective against TTKSK. One of these resistance genes, Sr13, was previously assigned to the long arm of chromosome 6A, but its precise map location was not known. In this study, the genome location of Sr13 was determined in four tetraploid wheat (T. turgidum ssp. durum) mapping populations involving the TTKSK resistant varieties Kronos, Kofa, Medora and Sceptre. Our results showed that resistance was linked to common molecular markers in all four populations, suggesting that these durum lines carry the same resistance gene. Based on its chromosome location and infection types against different races of stem rust, this gene is postulated to be Sr13. Sr13 was mapped within a 1.2–2.8 cM interval (depending on the mapping population) between EST markers CD926040 and BE471213, which corresponds to a 285-kb region in rice chromosome 2, and a 3.1-Mb region in Brachypodium chromosome 3. These maps will be the foundation for developing high-density maps, identifying diagnostic markers, and positional cloning of Sr13.     

Genetic structure of <Emphasis Type="Italic">Varroa destructor</Emphasis> populations infesting <Emphasis Type="Italic">Apis mellifera</Emphasis> colonies in Argentina

Although mitochondrial DNA mapping of Varroa destructor revealed the presence of several haplotypes, only two of them (Korean and Japanese haplotypes) were capable to infest Apis mellifera populations. Even though the Korean haplotype is the only one that has been reported in Argentina, these conclusions were based on mites sampled in apiaries from a specific geographical place (Buenos Aires province). To study mites from several sites of Argentina could reveal the presence of the Japanese genotype, especially considering sites near to Brazil, where Japanese haplotype was already detected. The aim of this work was to study the genetic structure of V. destructor populations from apiaries located in various provinces of Argentina, in order to determine the presence of different haplotypes. The study was carried out between January 2006 and December 2009. Phoretic adult Varroa mites were collected from honey bee workers sampled from colonies of A. mellifera located in Entre Ríos, Buenos Aires, Corrientes, Río Negro, Santa Cruz and Neuquén provinces. Twenty female mites from each sampling site were used to carry out the genetic analysis. For DNA extraction a nondestructive method was used. DNA sequences were compared to Korean haplotype (AF106899) and Japanese haplotype (AF106897). All DNA sequences obtained from mite populations sampled in Argentina, share 98% of similitude with Korean Haplotype (AF106899). Taking into account these results, we are able to conclude that Korean haplotype is cosmopolite in Argentina.     

New combinations and typifications in <Emphasis Type="Italic">Bistorta</Emphasis>, <Emphasis Type="Italic">Persicaria</Emphasis>, <Emphasis Type="Italic">Polygonum,</Emphasis> and <Emphasis Type="Italic">Rumex</Emphasis> (Polygonaceae)

New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.     

New species in <Emphasis Type="Italic">Barleria</Emphasis> sect. <Emphasis Type="Italic">Stellatohirta</Emphasis> (<Emphasis Type="Italic">Acanthaceae</Emphasis>) from Africa

Summary  Three new species are described in Barleria L. sect. Stellatohirta M. Balkwill from tropical Africa: B. aristata from south-central Tanzania, B. aenea from south-western Tanzania and northeast Zambia, and B. purpureotincta from south-western Zambia. Their affinities and conservation status are discussed.     

Quantitative study of interactions between <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> and <Emphasis Type="Italic">Oenococcus </Emphasis><Emphasis Type="Italic">oeni</Emphasis> strains

This study examines the interactions that occur between Saccharomyces cerevisiae and Oenococcus oeni strains during the process of winemaking. Various yeast/bacteria pairs were studied by applying a sequential fermentation strategy which simulated the natural winemaking process. First, four yeast strains were tested in the presence of one bacterial strain leading to the inhibition of the bacterial component. The extent of inhibition varied widely from one pair to another and closely depended on the specific yeast strain chosen. Inhibition was correlated to weak bacterial growth rather than a reduction in the bacterial malolactic activity. Three of the four yeast strains were then grown with another bacteria strain. Contrary to the first results, this led to the bacterial stimulation, thus highlighting the importance of the bacteria strain. The biochemical profile of the four yeast fermented media exhibited slight variations in ethanol, SO(2) and fatty acids produced as well as assimilable consumed nitrogen. These parameters were not the only factors responsible for the malolactic fermentation inhibition observed with the first bacteria strain. The stimulation of the second has not been reported before in such conditions and remains unexplained.     

Genetic variation in heat-stress tolerance among South American <Emphasis Type="Italic">Drosophila</Emphasis> populations

Spatial or temporal differences in environmental variables, such as temperature, are ubiquitous in nature and impose stress on organisms. This is especially true for organisms that are isothermal with the environment, such as insects. Understanding the means by which insects respond to temperature and how they will react to novel changes in environmental temperature is important for understanding the adaptive capacity of populations and to predict future trajectories of evolutionary change. The organismal response to heat has been identified as an important environmental variable for insects that can dramatically influence life history characters and geographic range. In the current study we surveyed the amount of variation in heat tolerance among Drosophila melanogaster populations collected at diverse sites along a latitudinal gradient in Argentina (24°–38°S). This is the first study to quantify heat tolerance in South American populations and our work demonstrates that most of the populations surveyed have abundant within-population phenotypic variation, while still exhibiting significant variation among populations. The one exception was the most heat tolerant population that comes from a climate exhibiting the warmest annual mean temperature. All together our results suggest there is abundant genetic variation for heat-tolerance phenotypes within and among natural populations of Drosophila and this variation has likely been shaped by environmental temperature.