Micropropagation of the endangered species Malus niedzwetzkyana for conservation biodiversity in Kazakhstan

In Vitro Cellular & Developmental Biology - Plant - Biodiversity conservation requires advanced and effective ex situ plant propagation techniques. The present study was conducted to optimize...     

Taxonomic differences among closely related pines Pinus sylvestris, P. mugo, P. uncinata, P. rotundata and P. uliginosa as revealed in needle sclerenchyma cells

The purpose of the present study was to test the taxonomic value of sclerenchyma in distinguishing Pinus sylvestris and P. mugo, P. uncinata, P. rotundata and P. uliginosa, all representing the subsection Sylvestres within the genus Pinus. Thirty-six samples were gathered in natural populations. Every sample was represented with 30 individuals, every individual with 10 brachyblasts. Three types of sclerenchymatic cells surrounding the resin canals and four between vascular bundles were distinguished. Relations among samples and taxa were verified using discriminant analysis and clustering based on Euclidean distances. The types of sclerenchymatic cells surrounding the resin canals and located between the vascular bundles differentiate the compared taxa when used as average frequencies but are extremely variable and do not allow the classification of every individual. The study demonstrated that the type of sclerenchymatic cells surrounding the resin canals and between the vascular bundles in needles could have an important taxonomic value in distinguishing the taxa of two-needle pines of the subsection Sylvestres in Europe at the population level. The distinguishing of individuals was difficult because of very high variation of sclerenchyma characters.     

Homology of the root adhesin of Pseudomonas fluorescens OE 28.3 with porin F of P. neruginosa and P. syringae

Summary A transformation system for the thermophilic cellulolytic fungus Talaromyces sp. CL240 has been developed, using the phleomycin resistance gene from Streptoalloteichus hindustanus (Sh ble) as a dominant selectable marker. The plasmids (pAN8-1 and pUT720) carrying the Sh ble gene under the control of the Aspergillus nidulans glyceraldehyde-3-phosphate dehydrogenase (gpd) promoter, allowed selection of phleomycin-resistant transformants. A new promoter sequence cloned from chromosomal DNA of Trichoderma reesei (pUT737) was also able to drive efficient expression of the Sh ble gene in Talaromyces sp. CL240, resulting in the selection of transformants that were highly resistant to phleomycin.     

Simultaneous phosphate solubilization potential and antifungal activity of new fluorescent pseudomonad strains, Pseudomonasaeruginosa, P. plecoglossicida and P. mosselii

Of 80 fluorescent pseudomonad strains screened for phosphate solubilization, three strains (BFPB9, FP12 and FP13) showed the ability to solubilize tri-calcium phosphate (Ca₃(PO₄)₂). During mineral phosphate solubilization, decrease of pH in the culture medium due to the production of organic acids by the strains was observed. These phosphate solubilizing strains produced indole-3-acetic acid (IAA) and protease as well as exhibited a broad-spectrum antifungal activity against phytopathogenic fungi. When tested in PCR using the gene-specific primers, strain BFPB9 showed the presence of hcnBC genes that encode hydrogen cyanide. On the basis of phenotypic traits, 16S rRNA sequence homology and subsequent phylogenetic analysis, strains BFPB9, FP12 and FP13 were designated as Pseudomonas aeruginosa, P. plecoglossicida and P. mosselii, respectively. Present investigation reports the phosphate solubilization potential and biocontrol ability of new strains that belong to P. plecoglossicida and P. mosselii. Because of the innate potential of phosphate solubilization, production of siderophore, IAA, protease, cellulase and HCN strains reported in this study can be used as biofertilizers as well as biocontrol agents.     

Semen cryopreservation and the conservation of endangered species

Currently, more than 16,000 plant and animal species are imminently threatened by extinction, often as a direct consequence of anthropogenic influences. One of the measures to halt that process is genetic resource banking. This short review focuses on mammal sperm cryopreservation in combination with assisted reproduction techniques. It summarizes general problems, recent developments, and currently applied protocols and gives an overview of hitherto existing successes of assisted reproduction measures in wild animals in the light of conservation efforts.     

Molecular evolution in Panagrolaimus nematodes: origins of parthenogenesis, hermaphroditism and the Antarctic species P. davidi

Background  

As exemplified by the famously successful model organism Caenorhabditis elegans, nematodes offer outstanding animal systems for investigating diverse biological phenomena due to their small genome sizes, short generation times and ease of laboratory maintenance. Nematodes in the genus Panagrolaimus have served in comparative development and anhydrobiosis studies, and the Antarctic species P. davidi offers a powerful paradigm for understanding the biological mechanisms of extreme cold tolerance. Panagrolaimus nematodes are also unique in that examples of gonochoristic, hermaphroditic and parthenogenetic reproductive modes have been reported for members of this genus. The evolutionary origins of these varying reproductive modes and the Antarctic species P. davidi, however, remain enigmatic.     

Altitudinal variation of UV-absorbing compounds in Plantago asiatica

UV-absorbing compounds such as flavonoids and phenolic acids are important for plants to protect their vegetative organs from harmful UV radiation at higher altitude. Two chemotypes, i.e., acteoside mainly-containing (AM) type and plantamajoside mainly-containing (PM) type were found by qualitative HPLC analysis of the phenolics in the leaves of Plantago asiatica in Mt. Norikura, Japan. Though AM type was not detected in low altitude populations, it occurred in high altitude populations. Acteoside has been reported to be more effective antioxidant than plantamajoside. On the other hand, higher accumulations of UV-absorbing substances were seen in higher altitude populations by quantitative analyses. Besides, B-ring ortho-dihydroxylated flavonoids notably increased than mono-hydroxylated flavonoids with increasing altitude. These results demonstrate that P. asiatica has chemically acclimated to high altitudes, in which severe environmental conditions such as higher UV radiation exist.     

Gas exchanges of an endangered species Syringa pinnatifolia and a widespread congener S. oblata

Net photosynthetic rate (P _N), transpiration rate (E), water use efficiency (WUE), stomatal conductance (g _s), and stomatal limitation (L_s) were investigated in two Syringa species. The saturation irradiance (SI) was 400 µmol m^-2s^-1 for S. pinnatifolia and 1 700 µmol m^-2s^-1 for S. oblata. Compared with S. oblata, S. pinnatifolia had extremely low g_s. Unlike S. oblata, the maximal photosynthetic rate (P _max) in S. pinnatifoliaoccurred around 08:00 and then fell down, indicating this species was sensitive to higher temperature and high photosynthetic photon flux density. However, such phenomenon was interrupted by the leaf development rhythms before summer. A relatively lower P _N together with a lower leaf area and shoot growth showed the capacity for carbon assimilation was poorer in S. pinnatifolia.This revised version was published online in March 2005 with corrections to the page numbers.     

Evidence of natural reciprocal hybridisation between Pinus uliginosa and P. sylvestris in the sympatric population of the species

Peat-bog pine Pinus uliginosa Neumann has become extinct or rare in many parts of Europe. It is supposed to hybridize with P. sylvestris but the influence of hybridization to genetic erosion of the P. uliginosa gene pool is unknown. In the presented study, the crossability between P. uliginosa and P. sylvestris was analyzed in a sympatric population at Węgliniec reserve in Poland. The aim of the study was to prove natural hybridisation and to estimate the influence of this phenomenon on possible natural gene pool erosion of peat-bog pine. A sequence polymorphism in the trnF–trnL cpDNA region of P. uliginosa and P. sylvestris was used to develop the species diagnostic PCR-RFLP marker. The marker of paternally transmitted cpDNA was applied in haplotype analyses of the progeny from open-pollinated P. uliginosa seeds (collected in 2000–2002) and from P. sylvestris ones (in 2002). An inconsistency in species diagnostic cpDNA haplotypes of seedlings and parental trees was observable both for P. uliginosa and P. sylvestris (about 1% and 2% of hybrids seeds, respectively). The results prove the occurrence of reciprocal hybridisation between the species. The influence of hybridisation on the natural gene pool protection and measures to reintroduce peat-bog pine is discussed.     

Efficient Plant Regeneration System From Leaf Discs of Zonal (Pelargonium x hortorum) and two scented (P. capitatum and P. graveolens) Geraniums

An efficient and rapid plant regeneration system was established for zonal and scented geraniums using leaf discs as explants. Several explants, medium and culture conditions were studied to optimize shoot induction. Leaf discs taken from 4–5 weeks old in vitro grown plants, whatever the genotype, were more effective for shoot regeneration than those taken from greenhouse grown plants. Darkness proved to be a stimulating factor for shoot regeneration and the combination between NAA and two cytokinins gave the best results. Direct shoot regeneration (100%) was obtained from leaf discs of P. capitatum on half-strength MS medium supplemented with 0.5 mg l⁻¹ NAA in combination with 1 mg l⁻¹ of BAP and zeatin in darkness (11.4 shoots per explant). In the same medium and culture conditions, all P. graveolens leaf discs also exhibited direct shoot regeneration (7.3 shoots per explant). For P. x hortorum, 100% of leaf discs underwent shoot regeneration on a MS medium supplemented with 0.2 mg l⁻¹ NAA in combination with 0.5 mg l⁻¹ of BAP and zeatin in darkness (8.8 shoots per explant) or under low light conditions with 0.2 mg l⁻¹ NAA and 1 mg l⁻¹ of BAP and zeatin (7.5 shoots per explant). For this species, the best results for shoot elongation were obtained on half-strength MS medium gelled with Phytagel 0.3% (v/v). Whatever the genotype, all shoots rooted readily when transferred to diluted MS medium (MS/2) containing 1 mg l⁻¹ IAA. Acclimatized plants grew normally and flowered in greenhouse conditions. Flow cytometry analysis made on leaves of acclimatized plants revealed that all the scented geranium plants are similar to mother plants while 71% of P. x hortorum plants which showed strong growth were tetraploid.     

Micropropagation of Turbinicarpus laui Glass et Foster, an endemic and endangered species

Summary In a short period of time, a large number of adventitious shoots were regenerated from longitudinal sections of in vitro-germinated seedlings of the endangered Mexican cactus, Turbinicarpus laui. The induction medium consisted of Murashige and Skoog salts, supplemented with 6-benzylaminopurine (BA) and α-naphthaleneacetic acid (NAA) in a wide range of combinations. The most effective concentrations of growth regulators for shoots initiation were 8.8–13.32 μM BA with 0–2.68 μM NAA. After 3–4 mo., individualized shoots were rooted on half-strength Murashige and Skoog medium and then transferred to soil to acclimatize under greenhouse conditions. In vitro strategies play a key role in the conservation and propagation of this commercially important endangered species of cactus.     

Population genetics of the threatened tree daisy Olearia gardneri (Asteraceae), conservation of a critically endangered species

All known populations of the nationally critical tree daisy, Olearia gardneri, were studied using AFLP markers. With fewer than 160 individual plants, Olearia gardneri is the third-rarest tree in New Zealand and a good model with which to study evolutionary process in fragmented endangered plants. Genetic variation was at similar levels to other long-lived tree species in New Zealand and also as in other studies to date had poor correspondence between genetic and geographic distance. Genetic factors such as inbreeding depression and the loss of genetic diversity might lower fitness and have substantial consequences for evolution and survival of rare threatened plants. Due to the decline of this species in recent times it is imperative that conservation measures are undertaken, including revegetation. Despite considerable emphasis on “eco-sourcing” in plant recovery programmes there is strong evidence that this may not be the best strategy for O. gardneri due to breeding system and population size considerations.     

Micropropagation of an endangered plant species: Coronopus navasii (Brassicaceae)

Plantlets of Coronopus navasii, an endangered species from SE Spain, were successfully regenerated from shoot and root segments excised from young seedlings. Initiation of multiple buds and development of leaves were obtained in MS modified medium plus l mg/l BAP and 0.1 mg/l NAA. Rooting was achieved by transfer of the isolated shoots to fresh MS medium without plant growth regulators. Plant survival of 47% was obtained six weeks after removal from in vitro culture conditions.Abbreviations BAP 6-benzylaminopurine - NAA naphthaleneacetic acid - MS medium see Murashige and Skoog 1962     

Growth and isoflavonoid accumulation of Pueraria candollei var. candollei and P. candollei var. mirifica cell suspension cultures

We established cell suspension cultures derived from leaf, stem, and root calli of Pueraria candollei var. candollei and P. candollei var. mirifica using liquid Murashige and Skoog (MS) medium supplemented with 0.56 μM 6-benzyladenine (BA) and 4.52 μM 2,4-dichlorophenoxyacetic acid (2,4-D). Growth of the cell suspension cultures progressed to the stationary phase within 15–24 days. Methanolic extracts of cell suspension cultures of both varieties of P. candollei were analyzed using a validated HPLC protocol. All cell lines derived from leaf, stem, and root explants produced four major isoflavonoids: daidzein, daidzin, genistein, and genistin; these isoflavonoids were detected only in the roots of intact plants. Furthermore, the isoflavonoid contents of the cell suspension cultures were higher than those of intact plants. Thus, cell suspension culture of both varieties of P. candollei may be an effective tool for isoflavonoid production.     

Host preference in Pseudacteon phorid flies: response of P. tricuspis and P. curvatus to black, red and hybrid imported Solenopsis fire ants in multiple choice bioassays

Host preferences in both sexes of Pseudacteon tricuspis Borgmeier (Jaguariuna biotype) and Pseudacteon curvatus Borgmeier (Formosa biotype) and their relative attraction to the imported fire ants (IFA), Solenopsis invicta Buren (red IFA), Solenopsis richteri Forel (black IFA) and S. invicta × S. richteri hybrids (hybrid IFA) were investigated in two separate experiments utilizing multiple choice flight bioassays. The results of both experiments clearly showed that both sexes of the Jaguariuna biotype of P. tricuspis could distinguish among the three IFA species and demonstrated greater preference for hybrid IFA and red IFA. This conclusion is supported by a variety of data collected on the number of fly visits, attack rate, and hovering duration (Experiment 1), and on the number of trapped flies (Experiment 2), which showed that black IFA is the least preferred of the three species. Similar results were recorded for the Formosan biotype of P. curvatus, although the data were not as strongly conclusive. Females of this biotype spent a significantly greater amount of time in hovering mode over red IFA and hybrid IFA compared to black IFA, but the other data were not significant. The red IFA is the natural host of both phorid fly biotypes and our results suggest that both biotypes may have evolved a specialized relationship with red IFA including an ability to discriminate it from related fire ants. These results are discussed in relation to the possible role of fire ant chemicals in mediating host preferences in phorid flies, contributions of male phorid flies to fire ant biocontrol, and the practical implications of the key findings.     

Chloroplast DNA Transgresses Species Boundaries and Evolves at Variable Rates in the California Closed-Cone Pines (Pinus radiata, P. muricata, and P. attenuata)

We studied phylogenetic relationships among populations and species in the California closed-cone pines (Pinus radiata D. Don, P. attenuata Lemm., and P. muricata D. Don) via chloroplast DNA restriction site analysis. Data on genetic polymorphism within and among 19 populations in the three species were collected using9 to 20 restriction enzymes and 38 to 384 trees. Because only five clades and extremely low intraclade diversity were found, additional phylogenetic data were collected using a single representative per clade and two outgroup species, P. oocarpa Schiede and P. jeffreyi Loud. In total, 25 restriction enzymes were employed and approximately 2.7 kb surveyed (2.3% of genome). The five clades recognized were Monterey pine, knob-cone pine, and the southern, intermediate, and northern races of bishop pine. On the basis of bootstrapping, both Wagner and Dollo parsimony analyses strongly separated the northern and intermediate races of bishop pine from the southern race; knobcone pine from Monterey and bishop pines; and the closed-cone pines from the two outgroups. Approximate divergence times were estimated for the lineages leading to knob-cone pine and to the intermediate and northern populations of bishop pine. The position of Monterey pine relative to bishop pine within their monophyletic clade was unresolved. Surprisingly, Montery pine and the southern race of bishop pine were much more similar to one another than was the southern race of bishop pine to its conspecific intermediate and northern races. Both the Monterey and southern bishop pine lineages also evolved severalfold more slowly than did the knobcone pine and intermediate-northern bishop pine lineages. These results differ significantly from a recent allozyme study, corroborating previous observations that chloroplast genome phylogeny can depart substantially from that of nuclear genes.