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1.
In order to study hybridisation, taxonomic boundaries and phylogeography in the genus Pseudopanax (Araliaceae), we developed seven novel microsatellite loci from enriched genomic libraries of P. lessonii and P. crassifolius. These loci were characterised in 16 individuals from a single population of P. crassifolius, and displayed 2–11 alleles per locus. Observed heterozygosities ranged from 0.063 to 0.688. Most loci were polymorphic in
the closely related Pseudopanax species, and several loci amplified widely across the Araliaceae. 相似文献
2.
Ardisia crenata, an evergreen shrub native to East Asia, has been a serious invasive plant to the southeastern USA. Here 13 polymorphic microsatellite
loci were isolated and characterized from an enrichment genomic library of A. crenata. The average allele number of these microsatellites was four per locus, ranging from two to seven. The ranges of observed
and expected heterozygosity were 0.000–1.000 and 0.239–0.789, respectively. These microsatellite markers will be useful for
investigating population genetics and reproductive ecology of A. crenata. 相似文献
3.
Fragmentation of natural habitats of the common vole (Microtus arvalis) provides an excellent model system to study the consequences of restricted gene flow and small population sizes for isolated
populations. Here we describe the isolation and characteristics of 10 autosomal and one X-linked microsatellite marker. These
new markers were tested in 24 voles from a natural population in eastern Germany. Loci were highly polymorphic with numbers
of alleles per locus ranging from three to 26 and expected heterozygosities from 0.51 to 0.97. All loci except for the X-linked
locus Mar105 followed Hardy–Weinberg expectations. Cross-species amplifications revealed that most loci were polymorphic as
well in M. agrestis, M. thomasi, and M. pennsylvanicus. 相似文献
4.
We studied the population genetics of two antimicrobial peptide (AMP) loci, called Mytilin B and Mytilus galloprovincialis defensin 2 (MGD2), in the secondary contact mosaic hybrid zone between Mytilus edulis and M. galloprovincialis. The isolation period between the two species was estimated to be ~1 million years (range, 0.5 million to 2 million years)
long. During this period, coevolution between microbes and the immune system has likely occurred. The secondary contact, which
would date back to ~25,000 (0–200,000) years, recently allowed these coadaptations to be rearranged through hybridization.
Distinctive polymorphisms were uncovered in coding sequences of the two AMP loci such as insertion/deletion of codons or bisubstituted
codons. Very low levels of differentiation were observed between populations of the two species at both loci, while other
nuclear loci often showed marked structure among the same samples. The absence of population differentiation proved to be
the consequence of secondary introgression of highly divergent alleles. While only a few recombinants were observed at the
Mytilin B locus, the MGD2 locus showed a high intragenic recombination rate, which increased in the exon coding for the mature peptide. In addition,
standard neutrality tests revealed significant deviations from the mutation-drift equilibrium at both loci. These results
suggest that either balancing or directional selection is likely to play a role in the evolution of the two AMPs and introgression
would be adaptive. However, evidence accumulated at the Mytilin B locus allows neither for identification of the direction of selection nor for any conclusions on whether selection acted
directly on the antimicrobial peptide itself. At the MGD2 locus, a spatial variation of polymorphism patterns along the sequence suggests that selection was direct, although the precise
nature of the selection (directional vs. balancing) remains unclear. This study concurs with previous reports of an effect
of slight selection on AMP genes evolution in other invertebrates, although selection does not necessarily act on the mature
peptides.
E. Boon and M. F. Faure contributed equally to this work. 相似文献
5.
Humulus japonicus in communities of Miscanthus sacchariflorus and Phragmites australis can grow large enough to overtop other species in the Amsa-dong floodplain. Because of strong winds and the weight of Humulus, plants of M. sacchariflorus and P. australis fell in mid-August and were subject to decomposition under its dense shading. To assess the effects of H. japonicus on nutrient cycling in these communities, we collected fresh samples of M. sacchariflorus and P. australis in litterbags and decomposed them under H. japonicus for 9 months, beginning in August. Biomass and organic contents from M. sacchariflorus during this incubation period were 49–51% and 44–48%, whereas those of P. australis were 49–61% and 32–52%, respectively. Their annual k values were 1.61–1.74 and 1.46–3.54, respectively. Initial N concentrations in M. sacchariflorus and P. australis were 13 and 20 mg g−1, while C:N ratios were 31 and 21, respectively. These results indicate that H. japonicus is responsible for the collapse of M. sacchariflorus and P. australis in August and also accelerates their nutrient cycling through rapid decomposition, thereby increasing nutrient circulation
in floodplains. 相似文献
6.
Rangan Parimalan Akshatha Venugopalan Parvatam Giridhar G. A. Ravishankar 《Plant Cell, Tissue and Organ Culture》2011,105(3):317-328
Establishment, maintenance, regeneration, and transformation of somatic embryos by both direct and indirect means (callus-mediated)
was achieved for Bixa orellana, a tropical plant whose seeds produce commercially edible ‘annatto pigment,’ which mainly constitutes an apocarotenoid called
bixin. Callus-mediated methodology was found to be efficient in producing a greater number of embryos in a short time. The
maximum of 28 somatic embryos were produced in 16–18 weeks when immature zygotic embryonic stalks were inoculated onto Murashige
and Skoog (MS) medium containing B5 vitamins supplemented with 0.44 μM benzyladenine (BA), 0.054 μM α-naphthaleneacetic acid
(NAA), 2.89 μM gibberellic acid (GA3), 0.02 μM triiodobenzoic acid (TIBA), and 0.011 μM triacontanol (TRIA). Callus initiation from hypocotyl explants was obtained
on MS medium supplemented with 1.07–2.14 μM NAA and 10.2 μM BA. In 3 months, somatic embryos were produced when callus was
inoculated onto MS medium supplemented with 4.44 μM BA, 40 μM AgNO3, and 0.011 μM TRIA. Somatic embryos were efficiently regenerated on MS basal solid and liquid media supplemented with 0.44–4.4 μM
BA, 0.54–2.69 μM NAA, 4.92 μM 2iP, 2.1 μM calcium d-pantothenate, 0.21 μM biotin, 227.7 μM cysteine HCl monohydrate, and 108.6 μM adenine sulfate. Agrobacterium tumefaciens GV 3101 harboring pCAMBIA 1305.2 binary vector-mediated stable transformation of somatic embryos exhibited a transformation
frequency of 2.56%. As somatic embryogenesis in any perennial system is useful in terms of both commercial and scientific
nature, this somatic embryo-based transformation protocol for the commercially important dye-yielding tropical plant B. orellana is useful for its improvement through genetic engineering. 相似文献
7.
Achnatherum sibiricum is a threaten and toxic perennial bunchgrass mainly in the north of China. We developed 11 polymorphic microsatellite loci
from A. sibiricum by combining biotin capture method. After validating and scoring, these loci were polymorphic in a test population with the
range of alleles from four to 13 per locus. The observed and expected heterozygosities ranged from 0.1649 to 0.5624 and from
0.3071 to 0.8826, respectively. All 11 microsatellite markers were in Hardy–Weinberg equilibrium. These polymorphic microsatellites
will be useful for genetic diversity analysis and population structure construction for A. sibiricum. 相似文献
8.
Nitraria retusa and Atriplex halimus (xero-halophytes) plants were grown in the range 0–800 mM NaCl while Medicago arborea (glycophyte) in 0–300 mM NaCl. Salt stress caused a marked decrease in osmotic potential and a significant accumulation of
Na+ and Cl− in leaves of both species. Moderate salinity had a stimulating effect on growth rate, net CO2 assimilation, transpiration and stomatal conductance for the xero-halophytic species. At higher salinities, these physiological
parameters decreased significantly, and their percentages of reduction were higher in A. halimus than in N. retusa whereas, in M. arborea they decreased linearly with salinity. Nitraria retusa PSII photochemistry and carotenoid content were unaffected by salinity, but a reduction in chlorophyll content was observed
at 800 mM NaCl. Similar results were found in A. halimus, but with a decrease in the efficiency of PSII (F′v/F′m) occurred at 800 mM. Conversely, in M. arborea plants we observed a significant reduction in pigment concentrations and chlorophyll fluorescence parameters. The marked
toxic effect of Na+ and/or Cl− observed in M. arborea indicates that salt damage effect could be attributed to ions’ toxicity, and that the reduction in photosynthesis is most
probably due to damages in the photosynthetic apparatus rather than factors affecting stomatal closure. For the two halophyte
species, it appears that there is occurrence of co-limitation of photosynthesis by stomatal and non-stomatal factors. Our
results suggest that both N. retusa and A. halimus show high tolerance to both high salinity and photoinhibition while M. arborea was considered as a slightly salt tolerant species. 相似文献
9.
A. V. Loskutov G.-Q. Song K. C. Sink 《In vitro cellular & developmental biology. Plant》2008,44(4):239-245
Callus selection (CS) and the flamingo-bill explant (FB) methods were evaluated for efficacy in transformation for celery.
Agrobacterium tumefaciens strains EHA105 and GV3101, each with the bar gene under the promoters NOS (pGPTV-BAR) or 35S (pDHB321.1), were used. Leaf explants were inoculated and co-cultivated for
2 d in the dark. Calluses emerged on the explants on callus medium (C), Murashige and Skoog (MS) medium + 2,4-Dichlorophenoxyacetic
acid (2,4-D) (2.3 μM) + kinetin (2.8 μM) + timentin (300 mg·l−1). Calluses 4- to 6-wk-old were selected for glufosinate (GS) resistance by a two step method. First, calluses were transferred
to C medium + GS 0.35, 0.5, 1, 2, 5, or 10 mg·l−1; calluses formed only with 0, 0.35 and 0.5 mg·l−1 GS. All growing calluses from 0 and 0.35 mg·l−1 and a few from 0.5 mg·l−1, were divided and placed back on C + GS 0.35–0.5 mg·l−1 for another 5–6 wk. Second, tolerant clones were again divided and placed on C + GS 1–50 mg·l−1. When cultivar XP85 was inoculated with both strains, using pGPTVBAR, 19 glufosinate resistant (GR) callus clones were selected,
but shoots regenerated only for strain EHA105 inoculations. When both of the strains (each with pDHB321.1) were inoculated
on cv. XP166, 3 and 12 GR calluses occurred for EHA105 and GV3101, respectively. Using CS, a total of 34 GR callus clones
were selected, and shoots were regenerated from over 50% of them on Gamborg B5 medium + 6-(γ, γ-dimethylallylamino) purine
2ip (4.9 μM) + naphthaleneacetic acid (NAA; 1.6 μM) and rooted on MS in 5–6 mo total time. Conversely, using FB with inoculation
by GV3101/pDHB321.1 on cv. XP166 yielded putative transgenic celery plants confirmed by polymerase chain reaction (PCR) in
just 6 wk. Transformation of the bar gene into celery was confirmed by PCR for 5 and 6 CS and FB lines, respectively. Southern blot analyses indicated 1–2 copies
in CS lines and 1 copy in FB lines. Herbicide assays on whole plants with 100 and 300 mg·l−1 glufosinate indicated a range of low to high tolerance for lines derived by both methods. The bar gene was found to be Mendelian inherited in one self-fertile CS derived line. 相似文献
10.
K. P. Singh R. K. Jaiswal Niranjan Kumar 《World journal of microbiology & biotechnology》2007,23(2):291-294
Summary
Catenaria anguillulae parasitized and killed the eggs and second stage juveniles (J2) of Meloidogyne graminicola under natural conditions. The percentage of infection in eggs was higher than J2 of M.␣graminicola, which ranged between 0–50.3% and 0–18.9% in 2004 and 0–46.6% and 0–21.7% in 2005, respectively. The higher parasitism of
eggs and J2 was recorded from those fields in which plants were severely infected with M. graminicola. The degree of parasitism of eggs and J2 by C. anguillulae varied with severity of root knot disease. The fields with a higher root gall index recorded a higher percentage of infection
in eggs and J2 of M. graminicola. In general, old galls when teased and incubated, recorded higher parasitism of eggs and juveniles than young galls. 相似文献
11.
Sclerocarya birrea (marula) is an indigenous South African tree with highly valued medicinal and nutritional properties. Induction of nodular
meristemoids from leaf explants was achieved on Murashige and Skoog (MS) and woody plant medium (WPM) supplemented with 6-benzyladenine
(BA) in combination with naphthalene acetic acid (NAA), indole-3-butryric acid (IBA) and indole-3-acetic acid (IAA). Induction
of nodular meristemoids from 86% of the leaf cultures was achieved on MS medium with 4.0 μM BA and 1.0 μM NAA. High levels
(78–100%) of induction were also achieved on WPM with different concentrations of BA (1.0–4.0 μM) and IBA (1.0–4.0 μM). The
highest conversion of meristemoids into shoots was only 22% for 4.0 μM BA and 1.0 μM NAA on MS initiation medium. This was
improved to 62% when nodular clusters were cultured in a MS liquid medium. Histological studies revealed the globular stage
of the nodular meristemoids. This protocol has potential for application in mass micropropagation and plant breeding of S. birrea. 相似文献
12.
In order to investigate the genetic diversity and structure of Hieracium pilosella L., we developed eleven pairs of primers for nuclear microsatellites through screening of three genomic DNA enriched libraries.
About 127 individuals from six locations of the Trentino region (Italy) were analysed. These loci were all polymorphic and
displayed 5–33 alleles per locus. These microsatellite markers constitute an efficient tool in investigating the genetic patterns
of H. pilosella L. populations. 相似文献
13.
Sushma Tamta Lok Man S. Palni Vijay K. Purohit Shyamal K. Nandi 《In vitro cellular & developmental biology. Plant》2008,44(2):136-141
An efficient and reproducible method for the regeneration of multiple shoots of brown oak (Quercus semecarpifolia Sm.) has been developed in which a part of the petiolar tube containing a primary shoot is used as the explant. Explants
derived from in vitro grown seedlings were cultured either on Murashige and Skoog or Woody Plant medium (WPM) containing different concentrations
of benzyladenine (BAP) throughout the range of 1–20 μM. WPM supplemented with 20 μM BAP was found to be best for adventitious
shoot induction and for the multiplication of individual shoots. In-vitro-produced shoots were rooted using a two-step method. Firstly, shoots were cultured on WPM containing indolebutyric acid (IBA)
at either 50 or 100 μM for 24 or 48 h. Secondly, the shoots were transferred to plant-growth-regulator-free half-strength
WPM. The second step not only considerably improved the rooting percentage but also minimized the formation of basal callus.
The most effective first-step treatment was found to be 100 μM IBA for 24 h, which initiated rooting at a frequency of 100%.
Well-rooted plants were transferred to plastic cups containing nonsterile, sieved soil and farmyard manure, hardened under
greenhouse conditions, and then successfully established in pots. This procedure is suitable for use in large-scale production
of plants and may have potential application in additional oak species. 相似文献
14.
Fawzeia H. Elmhalli Katinka Pålsson Jan Örberg Thomas G. T. Jaenson 《Experimental & applied acarology》2009,48(3):251-262
The toxicity of para-menthane-3,8-diol (PMD), the main arthropod-repellent compound in the oil of the lemon eucalyptus, Corymbia citriodora, was evaluated against nymphs of Ixodes ricinus using five methods (A–E) of a contact toxicity bioassay. Mortality rates were estimated by recording numbers of dead nymphs
at 30 min intervals during the first 5 h after the start of exposure and at longer intervals thereafter. The mortality rate
increased with increasing concentration of PMD and duration of exposure with a distinct effect after 3.5 h. From the results
obtained by methods A, C and E, the LC50 range was 0.035–0.037 mg PMD/cm2 and the LC95 range was 0.095–0.097 mg PMD/cm2 at 4 h of exposure; the LT50 range was 2.1–2.8 h and the LT95 range was 3.9–4.2 h at 0.1 mg PMD/cm2. To determine the duration of toxic activity of PMD, different concentrations (0.002, 0.01, 0.1 mg PMD/cm2) were tested and mortality was recorded at each concentration after 1 h; thereafter new ticks were tested. This test revealed
that the lethal activity of PMD remained for 24 h but appeared absent after 48 h. The overall results show that PMD is toxic
to nymphs of I. ricinus and may be useful for tick control. 相似文献
15.
We developed 11 polymorphic microsatellite markers for an endangered shrub Ammopiptanthus mongolicus using the Fast Isolation by AFLP of Sequences Containing repeats protocol. Polymorphism of each locus was assessed in 24
individuals from five natural populations of A. mongolicus. The average allele number of these markers was 4.2, ranging from 2 to 7. The observed (H
O) and expected (H
E) heterozygosities were 0.044–0.956 and 0.044–0.827, respectively. Further assessment in the congeneric species A. nanus revealed that nine of eleven loci were successfully amplified, but only two loci showed polymorphism. These markers provide
powerful tools for the conservation genetics studies of A. mongolicus. 相似文献
16.
F. W. Wang Z. M. Hou C. R. Wang P. Li D. H. Shi 《World journal of microbiology & biotechnology》2008,24(10):2143-2147
The metabolites of endophytic fungus Penicillium sp. from the leaf of Hopea hainanensis were reported for the first time. By bioassay-guided fractionation, the EtOAc extract of a solid-matrix steady culture of
this fungus afforded six compounds, which were identified through a combination of spectral and chemical methods (IR, MS,
1H- and 13C-NMR) to be monomethylsulochrin (1), rhizoctonic acid (2), asperfumoid (3), physcion (4), 7,8-dimethyl-iso-alloxazine (5) and 3,5-dichloro-p-anisic acid (6). Compounds 2, 3 and 6 were obtained from Penicillium sp. for the first time. All of the six isolates were subjected to in vitro bioactive assays including antifungal action against
three human pathogenic fungi Candida albicans, Trichophyton rubrum and Aspergillus niger and cytotoxic activity against the human nasopharyngeal epidermoid tumor KB cell line and human liver cancer HepG2 cell line.
As a result, compounds 2–4 and 6 inhibited the growth of C. albicans with MICs of 40.0, 20.0, 50.0 and 15.0 μg/ml, respectively and the compound 6 showed growth inhibition against A. niger with MICs of 40.0 μg/ml. In addition, compounds 1–3 and 6 exhibited cytotoxic activity against KB cell line with IC50 value of 30.0, 20.0, 20.0, 5.0 μg/ml, respectively and against HepG2 cell line with IC50 value of 30.0, 25.0, 15.0, 10.0 μg/ml, respectively. 相似文献
17.
Kouichi Kawamura Masashi Kubota Miki Furukawa Yasushi Harada 《Conservation Genetics》2007,8(5):1163-1176
The amago salmon, Oncorhynchus masou ishikawae, is an endemic subspecies of O. masou in Japan. Owing to the extensive stocking of hatchery fish throughout Japan, indigenous populations of O. m. ishikawae are now on the verge of extinction. We examined the genetic effects of stocking hatchery fish on wild populations in the
River Koza, Japan, using microsatellite and mitochondrial DNA (mtDNA) markers. For mtDNA, haplotype mt1, which is common in
wild populations, was present exclusively in isolated wild populations assumed to be unaffected by previous stocking, while
it was never observed in hatchery fish. Genetic diversity was much higher in wild populations in the stocked area, which shared
many mtDNA haplotypes with hatchery fish, than in isolated wild populations with haplotype mt1. Pairwise F
ST estimates based on microsatellites showed significant differentiation among the isolated populations with many microsatellite
loci monomorphic. Significant deviation from Hardy–Weinberg equilibrium was observed in wild populations in the area subject
to stocking, where a Bayesian-based assignment test showed a high level of introgression with hatchery fish. These results
suggest that wild populations with haplotype mt1, which became isolated through anthropogenic environmental change in the
1950–1960s, represent indigenous populations of O. m. ishikawae in the River Koza. They have low genetic diversity, most likely caused by genetic bottlenecks following damming and environmental
deterioration, while stocking of hatchery fish over the past 30 years apparently had a large impact on the genetic structure
of wild populations in the main channel of the River Koza. 相似文献
18.
We isolated and characterized seven microsatellite loci for the perennial herb Ixeridium dentatum ssp. dentatum, an apomictic triploid distributed throughout the lowland areas of East Asia. The number of alleles ranged from two to seven
in 32 screened individuals of I. dentatum ssp. dentatum from Japan. The observed and expected heterozygosities were 0.000–0.950 and 0.000–0.891, respectively, calculated using genotypes
of 20 individuals of I. dentatum ssp. nipponicum. One locus (msid4) deviated significantly from Hardy–Weinberg equilibrium (P = 0.0001). These microsatellites were also tested for cross-amplification in 11 other taxa of Lactuceae, including five endangered
taxa. These primers should be useful genetic tools not only for Ixeridium but also for other Lactuceae taxa. 相似文献
19.
Nitraria retusa and Atriplex halimus (xero-halophytes) plants were grown in the range 0–800 mM NaCl while Medicago arborea (glycophyte) in 0–300 mM NaCl. Plants were harvested after 120 days of salt-treatment. The present study was designed to
study the effect of salinity on root, stem and leaf anatomy, water relationship, and plant growth in greenhouse conditions.
Salinity induced anatomical changes in the roots, stems and leaves. The cuticle and epidermis of N. retusa and A. halimus stems were unaffected by salinity. However, root anatomical parameters (root cross section area, cortex thickness and stele
to root area ratio), and stem anatomical parameters (stem cross section area and cortex area) were promoted at 100–200 mM
NaCl. Indicating that low to moderate salinity had a stimulating effect on root and stem growth of these xero-halophytic species.
At higher salinities, root and stem structures were altered significantly, and their percentages of reduction were higher
in A. halimus than in N. retusa whereas, in M. arborea, they were strongly altered as salinity rose. NaCl (100–300 mM) reduced leaf water content by 21.2–56.2% and specific leaf
area by 51–88.1%, while increased leaf anatomical parameters in M. arborea (e.g. increased thickness of upper and lower epidermis, palisade and spongy mesophyll, entire lamina, and increased palisade
to spongy mesophyll ratio). Similar results were evidenced in A. halimus leaves with salinity exceeding 100 mM NaCl. Leaves of N. retusa were thinner in salt-stressed plants while epidermis thickness and water content was unaffected by salinity. The size of
xylem vessel was unchanged under salinity in the leaf’s main vein of the three species while we have increased number in M. arborea leaf main vein in the range of 200–300 mM NaCl. A longer distance between leaf vascular bundle, a reduced size and increased
number of xylem vessel especially in stem than in root vascular system was evidenced in M. arborea treated plants and only at (400–800 mM) in the xero-halophytic species. The effects of NaCl toxicity on leaf, stem and root
ultrastructure are discussed in relation to the degree of salt resistance of these three species. Our results suggest that
both N. retusa and A. halimus show high tolerance to salinity while M. arborea was considered as a salt tolerant species. 相似文献
20.
Neetu Singh Piyush Pandey R. C. Dubey D. K. Maheshwari 《World journal of microbiology & biotechnology》2008,24(9):1669-1679
Bacterial isolates having antifungal and good plant growth-promoting attributes were isolated from chir-pine (Pinus roxburghii) rhizosphere. An isolate, Bacillus subtilis BN1 exhibited strong antagonistic activity against Macrophomina phaseolina, and other phytopathogens including Fusarium oxysporum and Rhizoctonia solani. It was characterized and selected for the present studies. BN1 resulted in vacuolation, hyphal squeezing, swelling, abnormal
branching and lysis of mycelia. The cell-free culture filtrate of BN1 inhibited the growth of M. phaseolina. Pot trial study resulted in statistically significant increase in seedling biomass besides reduction in root rot symptoms
in chir-pine seedlings. BN1 treatment resulted in 43.6% and 93.54% increases in root and shoot dry weights respectively, as
compared to control. Also, 80–85% seed viability was recorded in treatments receiving BN1 either alone or in the presence
of M. phaseolina, compared to 54.5% with M. phaseolina. Bioinoculant formulation study suggested that maximum viability of bacteria was in a sawdust-based carrier. B. subtilis BN1 produced lytic enzymes, chitinase and β-1,3-glucanase, which are known to cause hyphal degradation and digestion of the
cell wall component of M. phaseolina. In the presence of M. phaseolina, population of B1 was 1.5 × 104 c.f.u. g−1 root after one month, which increased to 4.5 × 104 c.f.u. g−1 root in three months. Positive root colonization capability of B. subtilis BN1 proved it as a potent biocontrol agent. 相似文献