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1.
H. Y. Lee T. Kameya 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,82(4):405-408
Summary A rice plant resistant to 5-methyltryptophan (5MT) was selected from mutagenized M3 seeds (Oryza sativa L. var. Sasanishiki) originating from panicles treated with ethylene imine (0.2%) 2 h after flowering. When germinated on 5MT-containing medium, the seeds (M4) from selfed plants segregated with a 3 resistant:1 sensitive ratio, indicating that the plant was heterozygous for a resistance gene and that the resistance was dominant. The resistance was also expressed in callus derived from seeds. Analysis of the free amino acids in seeds, seedlings, and calli showed that homozygous resistant plants (TR1) contained higher levels of total free amino acids than sensitive plants. In particular the levels of tryptophan, phenylalanine, and histidine were, respectively, 8.5, 5.4, and 4.9 times higher than those in the sensitive plants. 相似文献
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Abstract A step by step protocol for resistant calli selection via a tissue culture technique under stress of Pyricularia oryzae culture filtrates was followed. Rice embryos dissected apart from the endosperm of susceptible rice seeds (Giza 176 and Riho) to P. oryzae produced embryonic calli on media containing various growth regulators of 2,4-D at concentrations of 0, 1, 1.5 and 2 mg/L and/or benzyl amino purine (BAP) at 0, 0.5, 1 and 1.5 mg/L when incubated under complete dark conditions for three weeks. Embryonic explants only produced shoots on media containing BAP. Selection of resistant calli was carried out in vitro under the challenging stress of increasing concentration of the pathogen P. oryzae culture filtrate (CF) from “0” up to 100%. The selection protocol has two directions. The first is step-by-step selection from lower to higher selective (CF) concentrations. The second is the exchangeable continuous cycles with and without the same selective (CF) concentration until the end of the selection regime to avoid calli adaptation to (CF). The regenerated calli to plantlets occurred under (CF) stress showed resistance and susceptibility when exposed to the pathogen infection under greenhouse conditions. The results reveal that the resistance in regenerated rice plantlets to P. oryzae pathogen segregated as 1 resistant: 2 moderate resistant: 1 susceptible giving the predication that the resistance in rice to P. oryzae may be controlled by one pair of genes. The in vitro selective regime via tissue cultures is advisable for the selection of novel disease resistant plants because of its time saving, space, money, it is easily applied and has a bio-safe approach. 相似文献
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Relationship of indole-3-acetic acid and tryptophan concentrations in normal and 5-methyltryptophan-resistant cell lines of wild carrots 总被引:1,自引:0,他引:1
Z. R. Sung 《Planta》1979,145(4):339-345
A 5-methyltryptophan(5-MT)-resistant cell line of wild carrot (Daucus carota L.), W001, that exhibited auxin-independent callus growth, was found to accumulate indole-3-acetic acid (IAA) and tryptophan (trp). Anthranilate-synthetase activity in W001 cell extract was less sensitive to feedback inhibition by trp than in the original 5-MT-sensitive cell lines. It is hypothesized that the resistant enzyme allowed more trp synthesis and accumulation which, in turn, affected the IAA concentration in the cell. Since carrot cultures cannot regenerate in the presence of exogenous auxin, the elevated IAA concentration in W001 may be responsible for its drastically reduced capacity to regenerate. The relationship between trp and IAA levels was further investigated by examining the effect of 2,4-dichlorophenoxy acetic acid (2,4-D) on the endogenous concentration of trp and IAA. In general, the IAA level was reduced but the trp concentration was elevated when 2,4-D was present in the culture medium.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- IAA
indole-3-acetic acid
- 5-MT
5-methyltryptophan
- 5-MTr
5-MT-resistant
- 5-MTs
5-MT-sensitive
- trp
tryptophan 相似文献
5.
T. J. Diedrick D. A. Frisch B. G. Gengenbach 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,79(2):209-215
Summary Regenerable maize (Zea mays L.) tissue cultures were selected for ability to grow in the presence of inhibitory (1.0–1.5 mM) concentrations of L-lysine plus L-threonine. Testcross kernels from one regenerated plant (LT20) segregated for wild-type and high free threonine concentration in a 11 ratio consistent with a single dominant gene for high free threonine. Free threonine concentrations (nmol/mg dry weight) increased an average of 29-fold in bulked F2 kernel samples from heterozygous mutant plants, and the total (free plus protein-bound) threonine concentration increased 68%. Increases in protein-bound methionine, lysine and glycine concentrations were also noted, suggesting a possible effect of the mutation on protein concentration and composition. Allelism tests with a previously selected mutant line, Ltr
*19, showed that two unlinked, codominant genes conditioned the high free threonine phenotype. Based on a separate study of aspartate kinase feedback inhibition characteristics in the two mutant lines, we propose that the mutant alleles [gene and allele designations are according to guidelines for maize genetic nomenclature (Burnham et al. 1975)] be designated Ask-LT19 and Ask2-LT20 for the Ltr
*19 and LT20 mutants, respectively. 相似文献
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E. S. Dennis R. I. S. Brettell W. J. Peacock 《Molecular & general genetics : MGG》1987,210(1):181-183
Summary We have found a null Adh1 allele which arose as a somaclonal variant following tissue culture of maize embryos carrying Adh1-1S and Adh1-1F alleles. Cloning and sequencing shows that the mutant allele derives from Adh1-1S and that there has been a single base change in the coding region of the gene which converts and AAG lysine codon to a TAG stop codon. The rate of nucleotide substitution (two per 218 embryos cultured) is much greater than normal mutation rates. 相似文献
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Gideon W. Schaeffer Frank T. Sharpe Jr. 《In vitro cellular & developmental biology. Plant》1981,17(4):345-352
Summary Rice cells derived from PI 353705 (similar to Assam 5) were isolated from anthers cultured on Blaydes medium containing IAA, 2,4-D, kinetin, yeast extract, and coconut milk. Isolated aggregates of cells were plated on a modified Blaydes medium containing 10−3 M S-aminoethyl-l-cysteine (S-AEC). This level ofS-AEC inhibits nonselected wild type cells. Cells or aggregates of cells resistant to this analog of lysine were subcultured three times in the presence of 2×10−3 M S-AEC. The selected cells were then placed on a Murashige-Skoog (MS) regenerating medium containing 1 mg/l each of IAA and kinetin. Ten plants were recovered from 34 selected cell lines, three plants grew to maturity, and two produced seeds. Seeds from plants regenerated from cells in culture had higher lysine than the original field controls and had increased levels of free alanine, arginine, and asparagine. The in vitro selection produced plants with higher protein than the field controls. Plant breeders have begun to evaluate the genotype recovered from in vitro selection. 相似文献
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Xanthan gum, a microbial desiccation-resistant polysaccharide prepared commercially by aerobic submerged fermentation from Xanthomonas campestris, has been successfully used as a solidifying agent for plant tissue culture media. Its suitability as a substitute to agar was demonstrated for in vitro seed germination, caulogenesis and rhizogenesis of Albizzia lebbeck, androgenesis in anther cultures of Datura innoxia, and somatic embryogenesis in callus cultures of Calliandra tweedii. Culture media used for eliciting these morphogenic responses were gelled with either 1% xanthan gum or 0.9% agar. Xanthan gum, like agar, supported all these responses. 相似文献
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`Isubgol', the mucilaginous husk derived from the seeds of Plantago ovata, was successfully used as a gelling agent in tissue culture media for in vitro seed germination, shoot formation and rooting in Syzygium cuminii and anther culture in Datura innoxia. For seed germination, Knop's basal medium supplemented with 1% sucrose was employed, whereas for the development of shoots the epicotyl segments excised from in vitro-developed seedlings were cultured on MS basal medium supplemented with 4% sucrose and 1 mg/l 6-benzyladenine. Shoots that developed from the epicotyl segments were rooted on Knop's medium enriched with 2% sucrose and 1 mg/l indole-3-acetic acid. The anthers of D. innoxia excised at the late uninucleate to early binucleate stages of microspore development were cultured on Nitsch's basal medium containing 2% sucrose. Media were either gelled with 0.9% agar or 3% `Isubgol'. The response on media gelled with `Isubgol' in each of the cases was similar to that on media solidified with agar. Received: 9 October 1996 / Revision received: 22 July 1996 / Accepted: 30 July 1997 相似文献
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High-performance liquid chromatography with electrochemical detection was used to measure the concentrations of 3,4-dihydroxyphenylethylamine (dopamine), 5-hydroxytryptamine (5-HT), p-hydroxyphenylethanolamine (octopamine), alpha-methyl-p-tyrosine, and tryptophan in the cerebral ganglia of cockroaches (Periplaneta americana) after peripheral administration of alpha-methyl-p-tyrosine and alpha-methyltryptophan. In addition, the levels of dopamine, 5-HT, octopamine, alpha-methyl-p-tyrosine, and tryptophan were determined after injection of alpha-methyl-p-tyrosine, 6-hydroxydopamine, or 5,7-dihydroxytryptamine directly into the cerebral ganglia by means of microinjection needles. Peripheral administration of alpha-methyl-p-tyrosine (400-1,600 micrograms/insect) caused a reduction in dopamine and 5-HT concentrations in cockroach cerebral ganglia, although the reduction in dopamine concentrations was more pronounced. Peripheral injections of alpha-methyl-p-tyrosine also reduced octopamine levels in the cerebral ganglia. Peripheral injection of alpha-methyltryptophan (400-1,600 micrograms/insect) caused a marked reduction in 5-HT and tryptophan concentrations in cockroach cerebral ganglia without altering dopamine or octopamine concentrations. Central injections of alpha-methyl-p-tyrosine (80 micrograms/insect) reduced dopamine concentrations in the cerebral ganglia. However, neither 6-hydroxydopamine (20 micrograms/insect) nor 5,7-dihydroxytryptamine (20 micrograms/insect) caused reductions in amine levels when applied near or directly into the cerebral ganglia. The results suggest that specific lesions of aminergic neurons in insects by either 6-hydroxydopamine or 5,7-dihydroxytryptamine are impractical. The specific, long-lasting depletion of 5-HT by alpha-methyltryptophan suggests that this chemical may be useful in elucidating the functions of 5-HT in insects. 相似文献
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Molecular characterization of ura1, a mutant allele for orotidine-5'-monophosphate decarboxylase in Schizophyllum commune 总被引:1,自引:0,他引:1
Abstract The basis of the auxotrophic ural phenotype in Schizophyllum commune has been investigated. Two point mutations causing changes in conserved amino acid positions 62 (from lysine to glutamate) and 79 (from leucine to phenylalanine) most likely are the cause for the observed phenotype, whereas the overall gene structure was unchanged. Since reversion rates in this locus are extremely low, a single point mutation could not be expected to be the cause for the mutation. Besides the two point mutations expected to be induced by UV mutagenesis, the two alleles investigated from independently isolated strains differ by approximately 7% in nucleic acid sequence and about 3% in amino acid sequence, indicating a distant relationship between the strains used. 相似文献
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蕨类植物组织培养研究进展(综述) 总被引:1,自引:0,他引:1
蕨类植物组织培养可分为以孢子为外植体的无菌播种和以孢子体为外植体进行的组织培养.本文简要介绍国内外蕨类植物组织培养研究概况,综述培养基成份、培养方式及培养条件对组织培养过程中生长发育的影响,同时介绍蕨类植物组织培养中世代转换的诱导及调控. 相似文献
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Mutant mice that lack serotonin(1A) receptors exhibit enhanced anxiety-related behaviors, a phenotype that is hypothesized to result from impaired autoinhibitory control of midbrain serotonergic neuronal firing. Here we examined the impact of serotonin(1A) receptor deletion on forebrain serotonin neurotransmission using in vivo microdialysis in the frontal cortex and ventral hippocampus of serotonin(1A) receptor mutant and wild-type mice. Baseline dialysate serotonin levels were significantly elevated in mutant animals as compared with wild-types both in frontal cortex (mutant = 0.44 +/- 0.05 n M; wild-type = 0.28 +/- 0.03 n M) and hippocampus (mutant = 0.46 +/- 0.07 n M; wild-type = 0.27 +/- 0.04 n M). A stressor known to elicit enhanced anxiety-like behaviors in serotonin(1A) receptor mutants increased dialysate 5-HT levels in the frontal cortex of mutant mice by 144% while producing no alteration in cortical 5-HT in wild-type mice. There was no phenotypic difference in the effect of this stressor on serotonin levels in the hippocampus. Fluoxetine produced significantly greater increases in dialysate 5-HT content in serotonin(1A) receptor mutants as compared with wild-types, with two- and three-fold greater responses being observed in the hippocampus and frontal cortex, respectively. This phenotypic effect was mimicked in wild-types by pretreatment with the serotonin(1A) antagonist 4-iodo-N-[2-[4-(methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinyl-benzamide (p-MPPI). These results indicate that deletion of central serotonin(1A) receptors results in a tonic disinhibition of central serotonin neurotransmission, with a greater dysregulation of serotonin release in the frontal cortex than ventral hippocampus under conditions of stress or increased interstitial serotonin levels. 相似文献
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171 mutations conferring resistance to the indole analogue 5-fluoroindole (5 FI) were isolated in the filamentous basidiomycete fungus Coprinus cinereus. 5 FI is thought to be toxic because it is converted intracellularly to 5-fluorotryptophan (5 FT) which feedback inhibits the first enzyme of the tryptophan biosynthetic pathway, anthranilate synthase. Mutations were assigned to five loci, iar-1-iar-5 on the basis of functional analyses and mapping experiments. iar-5 mutations mapped in the anthranilate synthase structural gene and gave rise to an enzyme feedback resistant to tryptophan and its analogue. Mutants at other loci had regulatory changes. iar-1 and iar-3 mutants had elevated levels of two pathway enzymes measured (anthranilate synthase and tryptophan synthase) and were cross resistant to analogues of other aromatic amino acids suggesting that the entire aromatic pathway was derepressed. iar-3 mutants were unable to degrade metabolically derived typtophan to anthranilic acid unlike iar-1 mutants which excreted high levels of anthranilic acid. iar-2 mutants appeared to have a constitutive degradative pathway. iar-4 mutants had a blocked degradative pathway and unusual levels of tryptophan pathway enzymes.Abbreviations 5 FI 5-fluoroindole - 5 FT 5-fluorotryptophan - pFP para-fluorophenylalanine - mFT meta-fluoro-tyrosine 相似文献
16.
Takasaki H Mahmood T Matsuoka M Matsumoto H Komatsu S 《Molecular genetics and genomics : MGG》2008,279(4):359-370
Gibberellins (GAs) regulate growth and development in higher plants. To identify GA-regulated proteins during rice leaf sheath
elongation, a proteomic approach was used. Proteins from the basal region of leaf sheath in rice seedling treated with GA3 were analyzed by fluorescence two-dimensional difference gel electrophoresis. The levels of abscisic acid-stress-ripening-inducible
5 protein (ASR5), elongation factor-1 beta, translationally controlled tumor protein, fructose-bisphosphate aldolase and a
novel protein increased; whereas the level of RuBisCO subunit binding-protein decreased by GA3 treatment. ASR5 out of these six proteins was significantly regulated by GA3 at the protein level but not at the mRNA level in the basal region of leaf sheaths. Since this protein is regulated not only
by abscisic acid but also by GA3, these results indicate that ASR5 might be involved in plant growth in addition to stress in the basal regions of leaf sheaths. 相似文献
17.
Glyphosate selected amplification of the 5-enolpyruvylshikimate-3-phosphate synthase gene in cultured carrot cells 总被引:6,自引:0,他引:6
Yu-Yau Joanne Shyr Angus G. Hepburn Jack M. Widhohn 《Molecular & general genetics : MGG》1992,232(3):377-382
Summary CAR and C1, two carrot (Daucus carota L.) suspension cultures of different genotypes, were subjected to stepwise selection for tolerance to the herbicide glyphosate [(N-phosphonomethyl)glycine]. The specific activity of the target enzyme, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), as well as the mRNA level and copy number of the structural gene increased with each glyphosate selection step. Therefore, the tolerance to glyphosate is due to stepwise amplification of the EPSPS genes. During the amplification process, DNA rearrangement did not occur within the EPSPS gene of the CAR cell line but did occur during the selection step from 28 to 35 mM glyphosate for the C1 cell line, as determined by Southern hybridization of selected cell DNA following EcoRI restriction endonuclease digestion. Two cell lines derived from a previously selected glyphosate-tolerant cell line (PR), which also had undergone EPSPS gene amplification but have been maintained in glyphosate-free medium for 2 and 5 years, have lost 36 and 100% of the increased EPSPS activity, respectively. Southern blot analysis of these lines confirms that the amplified DNA is relatively stable in the absence of selection. These studies demonstrate that stepwise selection for glyphosate resistance reproducibly produces stepwise amplification of the EPSPS genes. The relative stability of this amplification indicates that the amplified genes are not extrachromosomal.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- DTT
dithiothreitol
- EPSPS
5-enolpyruvylshikimate-3-phosphate synthase
- I50
50% inhibitory concentration
- Kb
Kilobase (pairs)
- PEP
phosphoenolpyruvate
- PMSF
phenylmethylsulfonyl fluoride
- PVPP
polyvinylpolypyrrolidone
- S-3-P
shikimate-3-phosphate 相似文献
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Richard Scott Christopher Clark Ann Mathews Sarah Yallop Michael R. Davey Paul Lazzeri Effie Mutasa-Göttgens 《Molecular breeding : new strategies in plant improvement》2003,11(2):121-125
Increased public concern and strict statutory regulations relating tothe generation and exploitation of genetically modified organisms, make itimperative to track accurately individual plants through DNA transformationprogrammes. The ability to rapidly retrieve information associated withspecifictransgenic events and to provide accurate reports on demand is an increasinglyimportant feature for public research laboratories. Transgenic Plant Monitor(TPM) has been developed as a database structured to allow efficient recording,monitoring and analysis of the extensive and complex data generated in planttissue culture and transformation experiments. TPM is built upon the widelyavailable Microsoft Access database engine and can be readily adoptedand/or adapted by other users. The key features and the utility of TPM as aresearch tool are discussed in this article. 相似文献