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1.

Key message

A novel non-destructive method is presented for studying the frost hardiness of roots. Principal component analysis from the electrical impedance spectra revealed differences between freezing temperatures, but no clear differences between the mycorrhizal treatments as regards freezing stress.

Abstract

We present a novel non-destructive method for the classification of root systems with different degrees of freezing injuries based on the measurement of electrical impedance spectra (EIS). Roots of Scots pine (Pinus sylvestris L.) seedlings, raised in perlite with nutrient solution, were colonized by Hebeloma sp. or Suillus luteus or left non-mycorrhizal, and exposed to a series of low temperatures (5, ?5, ?12 and ?18 °C) after cultivation with and without cold acclimation regimes. In EIS measurements, we ran a small-amplitude electric current to the root system at 44 frequencies between 5 Hz and 100 kHz through electrodes set in the stem and in perlite at the bottom of the container. The normalized (Euclidian) electrical impedance spectra were classified using the CLAFIC-method (CLAss-Featuring Information Compression) that is based on a subspace method with two variants where the longest projection vector defines the sample class. The current delivery through the root system was affected by freezing injuries in the roots. The most remarkable change, indicating the threshold for cold tolerance, took place between ?5 and ?12 °C for non-acclimated and between ?12 and ?18 °C for cold acclimated roots. No difference was found between the mycorrhizal treatments in the response to the freezing temperatures. The results on the effects of both the low-temperature exposure and mycorrhizas agree with freezing damage assessments done by other methods.
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2.

Key message

Our study shows that the expression of AtCBF3 and AtCOR15A improved the chilling tolerance in transgenic eggplant.

Abstract

In an attempt to improve chilling tolerance of eggplant (Solanum melongena L) plants, Arabidopsis C-repeat binding factor 3 (AtCBF3) and cold-regulated 15A (AtCOR15A) genes both driven by an Arabidopsis RESPONSIVE TO DESSICATION 29A promoter (AtRD29A) were transferred into the plants of eggplant cultivar Sanyueqie. Two independent homozygous transgenic lines were tested for their cold tolerance. The leaves of the transgenic plants in both lines withered much slower and slighter than the wild-type plants after exposure to cold stress treatment at 2 ± 1 °C. The gene expression of AtCBF3 and AtCOR15A was significantly increased as well as the proline content and the levels of catalase and peroxidase activities, while the relative electrical conductivity and the malondialdehyde content were remarkably decreased in the transgenic plants compared with the wild type at 4 ± 0.5 °C. The results showed that the expression of the exogenous AtCBF3 and AtCOR15A could promote the cold adaptation process to protect eggplant plants from chilling stress.  相似文献   

3.
4.
The alkaloids of Uncaria tomentosa micropropagated plantlets and root cultures were isolated and identified by NMR and mass spectrometry. Plantlets yielded pteropodine (1), isopteropodine (2), mitraphylline (3), isomitraphylline (4), uncarine F (5), speciophylline (6), rhynchophylline (7) and isorhynchophylline (8). In plantlets growing under continuous light, tetracyclic alkaloids 7 and 8 decreased from 20 ± 1.8 at 2 months to 2.2 ± 0.33 mg/g dry wt at 6 months, while the pentacyclic alkaloids 14 increased from 7.7 ± 1.4 to 15 ± 0.05 mg/g dry wt, supporting their biogenetic conversion. Micropropagated plantlets produced four times more alkaloids (27.6 ± 3.1 mg/g dry wt) than greenhouse plants. Plantlet roots yielded 3, 4, 8 and the glucoindole alkaloids 3α-dihydrocadambine (9) and dolichantoside (10), the last one not previously found in Uncaria.  相似文献   

5.

Key message

Phytophthora infestans resistant somatic hybrids of S. × michoacanum (+) S. tuberosum and autofused 4 x S. × michoacanum were obtained. Our material is promising to introgress resistance from S. × michoacanum into cultivated potato background.

Abstract

Solanum × michoacanum (Bitter.) Rydb. (mch) is a wild diploid (2n = 2x = 24) potato species derived from spontaneous cross of S. bulbocastanum and S. pinnatisectum. This hybrid is a 1 EBN (endosperm balance number) species and can cross effectively only with other 1 EBN species. Plants of mch are resistant to Phytophthora infestans (Mont) de Bary. To introgress late blight resistance genes from mch into S. tuberosum (tbr), genepool somatic hybridization between mch and susceptible diploid potato clones (2n = 2x = 24) or potato cultivar Rywal (2n = 4x = 48) was performed. In total 18,775 calli were obtained from postfusion products from which 1,482 formed shoots. The Simple Sequence Repeat (SSR), Cleaved Amplified Polymorphic Sequences (CAPS) and Random Amplified Polymorphic DNA (RAPD) analyses confirmed hybrid nature of 228 plants and 116 autofused 4x mch. After evaluation of morphological features, flowering, pollen stainability, tuberization and ploidy level, 118 somatic hybrids and 116 autofused 4x mch were tested for late blight resistance using the detached leaf assay. After two seasons of testing three somatic hybrids and 109 4x mch were resistant. Resistant forms have adequate pollen stainability for use in crossing programme and are a promising material useful for introgression resistance from mch into the cultivated potato background.  相似文献   

6.

Key message

Using DArT analysis, we demonstrated that all Solanum × michoacanum (+) S. tuberosum somatic hybrids contained all parental chromosomes. However, from 13.9 to 29.6 % of the markers from both parents were lost in the hybrids.

Abstract

Somatic hybrids are an interesting material for research of nucleus-cytoplasm interaction and sources of new nuclear and cytoplasmic combinations. Analyses of genomes of somatic hybrids are essential for studies on genome compatibility between species, its evolution and are important for their efficient exploitation. Diversity array technology (DArT) permits analysis of the composition of nuclear DNA of somatic hybrids. The nuclear genome compositions of 97 Solanum × michoacanum (+) S. tuberosum [mch (+) tbr] somatic hybrids from five fusion combinations and 11 autofused 4x mch were analyzed for the first time based on DArT markers. Out of 5358 DArT markers generated in a single assay, greater than 2000 markers were polymorphic between parents, of which more than 1500 have a known chromosomal location on potato genetic or physical map. DArT markers were distributed along the entire length of 12 chromosomes. We noticed elimination of markers of wild and tbr fusion components. The nuclear genome of individual somatic hybrids was diversified. Mch is a source of resistance to Phytophthora infestans. From 97 mch (+) tbr somatic hybrids, two hybrids and all 11 autofused 4x mch were resistant to P. infestans. The analysis of the structure of particular hybrids’ chromosomes indicated the presence of markers from both parental genomes as well as missing markers spread along the full length of the chromosome. Markers specific to chloroplast DNA and mitochondrial DNA were used for analysis of changes within the organellar genomes of somatic hybrids. Random and non-random segregations of organellar DNA were noted.
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7.
Seven organorhenium pentylcarbonate compounds (PC1PC7) have been synthesized. DNA-binding studies of the PC-series compounds using electronic spectroscopy and gel electrophoresis suggest that the compounds presumably bind to DNA in an intercalative mode. The intrinsic binding constants for PC4, PC6, and PC7 were found to be 1.6 × 104, 3.9 × 104, and 4.2 × 104 M?1, respectively. The X-ray structure determinations and density functional theory calculations indicate that the polypyridyl ligands in the compounds are nearly planar facilitating DNA binding through an intercalation mechanism. Cytotoxicity studies of 10 µM pentylcarbonate compounds against HTB-12 human astrocytoma brain cancer cells were studied for 48 h. It was observed that each of the pentylcarbonate compounds is active against the cancer cells. However, under analogous conditions, CRL-2005 rat astrocyte normal brain cells are not affected significantly.  相似文献   

8.

Key message

An improved isolated microspore culture protocol alleviating the recalcitrance typically observed in six-row spring barley was developed by optimizing four key physical factors to increase embryogenesis and reduce albinism.

Abstract

Doubled haploid (DH) plants are completely homozygous individuals that can be generated in just a few months via androgenesis in vitro. DHs are useful tools in genetic research and in plant breeding. Isolated microspore culture (IMC) is the most efficient way to produce DHs, but a strong genotype dependency imposes limitations to its wide application. Six-row, spring barley genotypes are considered as particularly recalcitrant due to a low frequency of embryogenesis and a high rate of albinism. Seeking to develop an efficient IMC protocol for this type of barley, we explored four important factors: (1) the harvest stage of immature spikes, (2) the type of pretreatment applied, (3) the osmotic potential in the induction medium, and (4) the plating density of microspores. This work was first performed using four barley genotypes: two typical six-row spring cultivars (ACCA and Léger), a two-row spring (Gobernadora) and a two-row winter (Igri) cultivar. First, by optimizing the harvest stage for each genotype we obtained a twofold to fourfold increase in the yield of embryogenic microspores. Second, two pretreatments (0.3 M mannitol for 2 days, or a combination of cold and heat over 15 days) both performed significantly better than the commonly used cold pretreatment (28 days at 4 °C). Third, an induction medium-containing mannitol (32 g/l) doubled green plant regeneration. Fourth, a plating density of 106 microspores/ml yielded the highest number of green regenerated plants. Our most important findings were then confirmed using sets of F1s from a six-row, spring-type breeding program.  相似文献   

9.
10.
A graphene nanoflake (GNF) is a polycyclic aromatic hydrocarbon (PAH) with a huge two-dimensional π-conjugated carbon material in which a central benzene ring is surrounded by identical benzene-type rings through infinite alternant method. In this paper, we explore the structure-aromaticity relationship of the GNFs and the GNFs with hollow sites (GNFHs) by combining the nucleus-independent chemical shifts (NICS) with the anisotropy of the current induced density (ACID). Firstly, the benzene is a typical aromatic molecule (NICS = ?9.671 ppm), GNFs 1-6 is darned with benzene and the corresponding GNFHs 1′-6′. Secondly, the NICS values of GNFs 1-6 alternately vary: ?1.214 (1) > ?13.847 (2) < ?2.662 (3) > ?14.530 (4) < ?3.932 (5) > ?13.978 (6) ppm, the GNFs (2, 4, 6) with even fragments of annulene have larger aromaticity than that of GNFs (1, 3, 5) with odd fragments of annulene. Significantly, the NICS values of GNFs 1-6 can also be fragment analyzed by the NICS values and ACID of benzene and corresponding GNFHs 1′-6′. The NICS values for GNFs (2, 4, 6) can be roughly estimated by the NICS value of benzene minus the NICS value of the GNFHs (2′, 4′, 6′), respectively. The NICS values for GNFs (1, 3, 5) can be roughly estimated by the NICS value of the GNFHs (1′, 3′, 5′) minus the NICS value of benzene, respectively. We hope that the present work can provide a simple and reliable method for the rational design of the GNF with aromaticity, which may be used to understand the origin of the graphene nanoflake aromatic properties.  相似文献   

11.

Objective

To produce (S)-3-hydroxy-1-(3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-4-(2,4,5-trifluorophenyl)butan-1-one (S)-1 from 4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro [1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)-1-(2,4,5-trifluorophenyl)butan-2-one (2) by microbial bioreduction.

Results

A new isolate of Pseudomonas pseudoalcaligenes reduced enantioselectively prochiral ketone 2 to chiral alcohol (S)-1. Whole cells of the bacterium were tolerant towards 20 % (v/v) DMSO and 10 g 2/l. Under the optimal conditions, the preparative-scale bioreduction yielded (S)-1 at 90 % yield and >99 % ee. Cells could be re-used with the yield and ee of product being 45 % and >99 %, respectively, after five cycles.

Conclusion

Bioreduction using whole cells of P. pseudoalcaligenes is an attractive approach to produce (S)-1, as a chiral intermediate of the anti-diabetic drug, sitagliptin.
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12.

Key message

A novel QTL for grain number, GN4-1, was identified and fine-mapped to an ~ 190-kb region on the long arm of rice chromosome 4.

Abstract

Rice grain yield is primarily determined by three components: number of panicles per plant, grain number per panicle and grain weight. Among these traits, grain number per panicle is the major contributor to grain yield formation and is a crucial trait for yield improvement. In this study, we identified a major quantitative trait locus (QTL) responsible for rice grain number on chromosome 4, designated GN4-1 (a QTL for Grain Number on chromosome 4), using advanced segregating populations derived from the crosses between an elite indica cultivar ‘Zhonghui 8006’ (ZH8006) and a japonica rice ‘Wuyunjing 8’ (WYJ8). GN4-1 was delimited to an ~ 190-kb region on chromosome 4. The genetic effect of GN4-1 was estimated using a pair of near-isogenic lines. The GN4-1 gene from WYJ8 promoted accumulation of cytokinins in the inflorescence and increased grain number per panicle by ~ 17%. More importantly, introduction of the WYJ8 GN4-1 gene into ZH8006 increased grain yield by ~ 14.3 and ~ 11.5% in the experimental plots in 2014 and 2015, respectively. In addition, GN4-1 promoted thickening of the culm and may enhance resistance to lodging. These results demonstrate that GN4-1 is a potentially valuable gene for improvement of yield and lodging resistance in rice breeding.
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13.
14.

Key Message

The critical level for SO 2 susceptibility of Populus × canescens is approximately 1.2 μL L ?1 SO 2 . Both sulfite oxidation and sulfite reduction and assimilation contribute to SO 2 detoxification.

Abstract

In the present study, uptake, susceptibility and metabolism of SO2 were analyzed in the deciduous tree species poplar (Populus × canescens). A particular focus was on the significance of sulfite oxidase (SO) for sulfite detoxification, as SO has been characterized as a safety valve for SO2 detoxification in herbaceous plants. For this purpose, poplar plants were exposed to different levels of SO2 (0.65, 0.8, 1.0, 1.2 μL L?1) and were characterized by visible injuries and at the physiological level. Gas exchange parameters (stomatal conductance for water vapor, CO2 assimilation, SO2 uptake) of the shoots were compared with metabolite levels (sulfate, thiols) and enzyme activities [SO, adenosine 5′-phosphosulfate reductase (APR)] in expanding leaves (80–90 % expanded). The critical dosage of SO2 that confers injury to the leaves was 1.2 μL L?1 SO2. The observed increase in sulfur containing compounds (sulfate and thiols) in the expanding leaves strongly correlated with total SO2 uptake of the plant shoot, whereas SO2 uptake rate was strongly correlated with stomatal conductance for water vapor. Furthermore, exposure to high concentration of SO2 revealed channeling of sulfite through assimilatory sulfate reduction that contributes in addition to SO-mediated sulfite oxidation to sulfite detoxification in expanding leaves of this woody plant species.  相似文献   

15.
Four new platinum(II) complexes: PtII L1·H2O (C1, H2 L1 = C20H16N2O2), PtII L2Cl2 (C2, L2 = C22H16N2O2), PtII L3Cl2·H2O (C3, L3 = C20H16N2), PtII L4Cl2·0.4H2O (C4, L4 = C18H14N4) have been synthesized and characterized by using various physico-chemical techniques. The binding interaction of the four platinum(II) complexes C1C4 with calf thymus (CT)-DNA has been investigated by UV–Vis and fluorescence emission spectrometry. The apparent binding constant (K app) values follow the order: C3 > C1 > C2 > C4. In addition, fluorescence spectrometry of bovine serum albumin (BSA) with the four platinum(II) complexes C1C4 showed that the quenching mechanism might be a static quenching procedure. For C1C4, the number of binding sites was about one for BSA and the binding constants follow the order: C3 (7.08 × 105M?1) > C1 (2.82 × 105M?1) > C2 (0.85 × 105M?1) > C4 (0.15 × 105M?1). With the single condition change such as absence of an external agent, the DNA cleavage abilities of C3 exhibit remarkable changes. In addition, the cytotoxicity of C3 in vitro on tumor cells lines (MCF-7, HepG2 and HT29) were examined by MTT and showed better antitumor effects on the tested cells.  相似文献   

16.
Complexes [Au(2Ac4oT)Cl][AuCl2] (1), [Au(Hpy2Ac4mT)Cl2]Cl·H2O (2), [Au(Hpy2Ac4pT)Cl2]Cl (3), [Pt(H2Ac4oT)Cl]Cl (4), [Pt(2Ac4mT)Cl]·H2O (5), [Pt(2Ac4pT)Cl] (6) and [Pt(L)Cl2OH], L = 2Ac4mT (7), 2Ac4oT (8), 2Ac4pT (9) were prepared with N(4)-ortho- (H2Ac4oT), N(4)-meta- (H2Ac4mT) and N(4)-para- (H2Ac4pT) tolyl-2-acetylpyridine thiosemicarbazone. The cytotoxic activities of all compounds were assayed against U-87 and T-98 human malignant glioma cell lines. Upon coordination cytotoxicity improved in 2, 5 and 8. In general, the gold(III) complexes were more cytotoxic than those with platinum(II,IV). Several of these compounds proved to be more active than cisplatin and auranofin used as controls. The gold(III) complexes probably act by inhibiting the activity of thioredoxin reductase enzyme whereas the mode of action of the platinum(II,IV) complexes involves binding to DNA. Cells treated with the studied compounds presented morphological changes such as cell shrinkage and blebs formation, which indicate cell death by apoptosis induction.  相似文献   

17.

Key message

Site-directed mutagenesis of nitrate reductase genes using direct delivery of purified Cas9 protein preassembled with guide RNA produces mutations efficiently in Petunia × hybrida protoplast system.

Abstract

The clustered, regularly interspaced, short palindromic repeat (CRISPR)-CRISPR associated endonuclease 9 (CRISPR/Cas9) system has been recently announced as a powerful molecular breeding tool for site-directed mutagenesis in higher plants. Here, we report a site-directed mutagenesis method targeting Petunia nitrate reductase (NR) gene locus. This method could create mutations efficiently using direct delivery of purified Cas9 protein and single guide RNA (sgRNA) into protoplast cells. After transient introduction of RNA-guided endonuclease (RGEN) ribonucleoproteins (RNPs) with different sgRNAs targeting NR genes, mutagenesis at the targeted loci was detected by T7E1 assay and confirmed by targeted deep sequencing. T7E1 assay showed that RGEN RNPs induced site-specific mutations at frequencies ranging from 2.4 to 21 % at four different sites (NR1, 2, 4 and 6) in the PhNR gene locus with average mutation efficiency of 14.9 ± 2.2 %. Targeted deep DNA sequencing revealed mutation rates of 5.3–17.8 % with average mutation rate of 11.5 ± 2 % at the same NR gene target sites in DNA fragments of analyzed protoplast transfectants. Further analysis from targeted deep sequencing showed that the average ratio of deletion to insertion produced collectively by the four NR-RGEN target sites (NR1, 2, 4, and 6) was about 63:37. Our results demonstrated that direct delivery of RGEN RNPs into protoplast cells of Petunia can be exploited as an efficient tool for site-directed mutagenesis of genes or genome editing in plant systems.
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18.

Key message

We investigated a Frankia Alnus sieboldiana symbiosis, including the minimum inoculum dose for constant nodulation, the period of time to nodulation after inoculation, and the effects of N on nodulation.

Abstract

Frankia is a nitrogen-fixing actinomycete that forms root nodules in some dicotyledonous plants, which are called actinorhizal. We studied nodule formation in Alnus sieboldiana, an actinorhizal plant, after inoculation with a Frankia isolate to establish techniques for Frankia inoculation and the cultivation of inoculated plants. Root nodules formed on seedlings of A. sieboldiana by 2 weeks after inoculation, and N2 fixation measured by acetylene reduction activity started 3 weeks after inoculation. Nodulation was observed after inoculation with a Frankia isolate at 0.001 μL packed cell volume (pcv). The number of nodules formed on the seedlings inoculated with Frankia at more than 0.05 μL pcv was not significantly different. Nodule development and N2 fixation were reduced when inoculated seedlings were treated weekly with 15 mM NH4NO3-N. In contrast, treatment with 3.75 or 0.9375 mM NH4NO3-N did not inhibit nodule development or N2 fixation of inoculated seedlings by 15 weeks of N treatment.
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19.

Key message

A high-quality rice activation tagging population has been developed and screened for drought-tolerant lines using various water stress assays. One drought-tolerant line activated two rice glutamate receptor-like genes. Transgenic overexpression of the rice glutamate receptor-like genes conferred drought tolerance to rice and Arabidopsis.

Abstract

Rice (Oryza sativa) is a multi-billion dollar crop grown in more than one hundred countries, as well as a useful functional genetic tool for trait discovery. We have developed a population of more than 200,000 activation-tagged rice lines for use in forward genetic screens to identify genes that improve drought tolerance and other traits that improve yield and agronomic productivity. The population has an expected coverage of more than 90 % of rice genes. About 80 % of the lines have a single T-DNA insertion locus and this molecular feature simplifies gene identification. One of the lines identified in our screens, AH01486, exhibits improved drought tolerance. The AH01486 T-DNA locus is located in a region with two glutamate receptor-like genes. Constitutive overexpression of either glutamate receptor-like gene significantly enhances the drought tolerance of rice and Arabidopsis, thus revealing a novel function of this important gene family in plant biology.  相似文献   

20.

Key message

GmPAP4 , a novel plant PAP gene in soybean, has phytase activity. Over-expressing GmPAP4 can enhance Arabidopsis growth when phytate is the sole P source in culture.

Abstract

Phosphorus (P) is an important macronutrient for plant growth and development. However, most of the total P in soils is fixed into organic phosphate (Po). Purple acid phosphatase (PAP) can hydrolyze Po in the soil to liberate inorganic phosphate and enhance plant P utilization. We isolated a novel PAP gene, GmPAP4, from soybean (Glycine max). It had an open reading frame of 1,329 bp, encoding 442 amino acid residues. Sequence alignment and phylogenetics analysis indicated that GmPAP4 was similar to other plant PAPs with large molecular masses. Quantitative real-time PCR analysis showed that the induced expression of GmPAP4 was greater in P-efficient genotype Zhonghuang15 (ZH15) than in P-inefficient genotype Niumaohuang (NMH) during the periods of flowering (28–35 days post phytate stress; DPP) and pod formation (49–63 DPP). Moreover, peak expression, at 63 DPP, was about 3-fold higher in ‘ZH15’ than in ‘NMH’. Sub-cellular localization showed that GmPAP4 might be on plasma membrane or in cytoplasm. Over-expressing GmPAP4 in Arabidopsis resulted in significant rises in P acquisition and utilization compared with the wild-type (WT). Under phytate condition, transgenic Arabidopsis plants showed increases of approximately 132.7 % in dry weight and 162.6 % in shoot P content compared with the WT. Furthermore, when phytate was added as the sole P source in cultures, the activity of acid phosphatase was significantly higher in transgenic plants. Therefore, GmPAP4 is a novel PAP gene that functions in plant’s utilization of organic phosphate especially under phytate condition.  相似文献   

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