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991.
几种玉米基因转移技术的研究及转基因植株的获得 总被引:23,自引:0,他引:23
用基因枪、超声波和子房注射法转化玉米,所用质粒pB48.415带有3’端截短的Bt毒蛋白基因和潮霉素磷酸转移酶(hpt)基因。用基因枪轰击玉米胚性愈伤组织和幼胚,超声波处理玉米胚性愈伤组织,用自制的微玻针注射授粉后l0~20h的玉米子房,均已成功地获得了转Bt基因的玉米檀株.点杂交和Southern吸印杂交的结果都证明在转基因玉米檀株中存在Bt毒蛋白基因。 相似文献
992.
993.
玉米愈伤组织对草丁膦的抗性及氨基酸对这种抗性的影响 总被引:4,自引:0,他引:4
将玉米(ZeamaysL.)(P910×Z31)愈伤组织接种于含不同浓度草丁膦及不同氨基酸的N6培养基上,测定愈伤组织重量增长及NH+4积累水平。统计结果表明,当培养基中草丁膦浓度为4mg/L时,愈伤组织重量增长最低;浓度为8mg/L时,NH+4积累水平达最高。综合考虑这两种因素,在培养基上选择转化体的草丁膦浓度以6mg/L为宜。在含有草丁膦的选择培养基上,L精氨酸和L谷氨酸能通过代谢调节显著降低玉米愈伤组织中的NH+4浓度;而L脯氨酸虽明显促进玉米愈伤组织在选择培养基上的重量增长,但并不降低玉米愈伤组织中的NH+4浓度 相似文献
994.
Efficient transformation of scutellar tissue of immature maize embryos 总被引:20,自引:0,他引:20
R. Brettschneider D. Becker H. Lörz 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(6-7):737-748
An efficient transformation system for maize was established by improving transformation conditions for the particle bombardment
of the scutellar tissue of immature embryos. Particle bombardment was carried out using constructs containing the pat gene as the selection marker and a PDS 1000/He gun (Biorad). Transformation parameters, such as the amount of gold particles
used per bombardment, particle velocity, preculture time of the scutellum prior to bombardment and osmotic treatment of the
target tissue before and after bombardment, were analysed. Fertile transgenic regenerants of the maize inbred lines H99, A188
and Pa91 and the crosses A188×H99 and Pa91×H99 were selected on Basta-containing medium. The transformation frequency was
between 2% and 4%. A total of 29 transgenic plant lines was obtained and verified with Southern blot analysis. All of the
transgenic plants were fertile and set seeds. The R1 progeny of single plants was analysed. A Mendelian segregation of the
transgenes was observed for all of the transformants tested. For 1 candidate, stable inheritance and stable expression of
the transgenes were followed up to the R4 generation.
Received: 28 October 1996/Accepted: 15 November 1996 相似文献
995.
A Cavallini L. Natali G. Cionini C. Balconi F. D’Amato 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(6-7):782-787
The nuclear DNA content (ploidy level) of maize leaf-epidermal cells was investigated by Feulgen cytophotometry in two lines,
Illinois High Protein (IHP) and Illinois Low Protein (ILP), their reciprocal hybrids, and their F2s. Epidermal cells have a 2C, 4C or 8C nuclear DNA content. The mean DNA content per nucleus in IHP was significantly higher
than in ILP; the mean DNA content per nucleus in hybrids was intermediate between the parental lines, and the same DNA content
was measured in reciprocal crosses. In F2s the same mean DNA content as in F1s was observed but with larger variability than in the F1, possibly indicating genetic segregation. It is inferred that the ploidy level in the leaf epidermis is inherited, and incomplete
dominance occurs in hybrids. The same behaviour in the different genotypes was observed for epidermal cell-surface area, except
that an increase of mean surface area occurred in the F1, probably due to heterotic effects. The difference in the accumulation of 4C and 8C nuclei in leaf epidermis parallels that
reported between two genotypes for the endosperm tissue: to the greater chromosome endoreduplication found in the endosperm
there were correspondingly higher frequencies of 4C and 8C nuclei in the leaf epidermis, indicating a higher general tendency
to chromosome endoreduplication in IHP than in ILP. It is suggested that the accumulation of 4C nuclei (G2-block) in the leaf epidermis may be regarded as the initial step of chromosome endoreduplication, the two phenomena being
related to the control of the sequence DNA synthesis-mitosis, possibly involving the same genes in both endosperm and leaf.
However, the inheritance of DNA content per nucleus in epidermal tissue seems to be different from that observed in endosperm
tissue of the same genotypes, suggesting that differences may occur in the regulation of the activity of these genes.
Received: 19 November 1996 / Accepted: 29 November 1996 相似文献
996.
远缘杂种孤雌生殖系Giemsa C—带的遗传稳定性分析 总被引:5,自引:1,他引:4
利用GiemsaC-显带方法发现在玉米自交系自330和二倍体多年生类玉米远缘杂交孤雌生殖后代中出现广泛的C-带结构异染色质变异,表现为C-带数目和分布位置的变化以及异配型C-带的出现。这种变异不仅存在于表型不稳定的早代孤雌系中,而且还存在于表型稳定的高代系中。造成这种变异的原因可能是因为远缘种质的引入影响到遗传平衡进而引起染色体发生结构重排并引起染色质的变化,这种变化与玉米染色体组中非同源染色体间存在的同源片段和因此造成的减数分裂过程中非同源染色体配对有着直接的关系。这些研究对于认识孤雌生殖育种的理论基础和应用价值具有重要意义。 相似文献
997.
《Molecular & general genetics : MGG》1997,255(6):580-586
The bz-m1 mutation in maize was one of the first to arise by direct transposition of the chromosome-breaking Ds element from its original or `standard' location in chromosome 9S to a known locus in the same chromosome arm. Thus, elucidation of its structure should shed light on the nature of the original
Ds element described by McClintock in 1948. The Ds insertion in bz-m1 has been reported to be only 1.2 kb long – much shorter than other chromosome-breaking Ds elements that have been described. We have characterized here the Ds element in our bz-m1 stocks and have confirmed by genetic and molecular tests that, in the presence of Ac, it acts as a chromosome breaker. The Ds insertion at bz-m1 is 1260 bp long. Besides its normal 5′ and 3′ ends, it contains an internal 3′ end at the same junction as the chromosome-breaking
double Ds element that has been found in several sh mutations. Thus, it appears to have arisen from the 4.1-kb double Ds by internal deletion of 2.9 kb. Because the element has lost one internal 5′ end, but retains the chromosome-breaking properties
of double Ds, we have named it sesqui-Ds (sDs). The origin, structure and properties of sDs vis-à-vis double Ds support the hypothesis that double Ds corresponds to the chromosome-breaking Ds element at the `standard' location in 9S.
Received: 10 March 1997 / Accepted: 2 May 1997 相似文献
998.
The expansion of maize root-cap mucilage during hydration. 3. Changes in water potential and water content 总被引:3,自引:0,他引:3
Root-cap mucilage from aerial nodal roots of maize has been found to have water potential values of −11 MPa or lower when air dried. The value approaches 0 MPa within 2 min of hydration in distilled water. In this time the expanding gel absorbs only about 0.3% of the water content of fully expanded mucilage. It is concluded that the root-cap mucilage per se has almost no capacity to retain water in the rhizosphere. Any function that it may play in the slowing of root desiccation would be indirect. For example, mucilage might decrease pore size between and within soil aggregates by pulling the particles together in a cycle of nocturnal efflux of water from the root surface, and diumal dyring during transpiration. 相似文献
999.
Summary Five genes of the -zein subfamily four (SF4) are located in a 56 kb genomic region of the maize inbred line W22. Their nucleotide and deduced amino acid sequences have been determined. The sequences define two types of -zein SF4 genes — type 1 (T1) and type 2 (T2). The single T1 -zein SF4 gene codes for an -zein protein with a Mr of about 22 000. This is the first -zein SF4 gene sequenced that contains no early in-frame stop codons in its coding sequence. The four T2 -zein SF4 genes in this cluster contain one or two early in-frame stop codons. In addition, our T1 and T2 genes differ markedly in the base sequences of their distal 5 non-translated flanking regions. The nucleotide and the deduced amino acid sequences of these two types of -zein SF4 genes are similar ( > 90 %) to one another and to all known -zein SF4 genes and cDNAs. Of the known W22 -zein SF4 genes, only one in six does not contain an early in-frame stop codon. If the number of -zein SF4 genes is 15–20, then we estimate that only about 4 of the W22 -zein SF4 genes are without in-frame early stop codons. 相似文献
1000.
J. W. Paulis J. A. Bietz T. P. Bogyo T. C. Nelsen L. L. Darrah M. S. Zuber 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1992,85(4):407-414
Summary Zeins, the major endosperm proteins in maize (Zea mays L.), are deficient in the essential amino acids lysine and tryptophan. Some mutant genes, like opaque-2 (o2) and floury-2 (fl2), reduce the levels of A- and B-zeins, thereby improving maize's nutritional value. Other mutants, such as amylose-extender (ae), floury-1 (fl1), soft starch (h), dull-1 (du), shrunken-1 (sh1), sugary-1 (su1), sugary-2 (su2), and waxy (wx), primarily affect starch composition, but also alter zein composition. We undertook this study to examine the effects of some of these mutant genes on A/B-zein composition and to study the interactions of these genes in double-mutant combinations. Endosperm prolamins were extracted from inbred B37, ten near-isogenic single mutants (ae, du, fl1, fl2, h, o2, sh1, su1, su2, and wx), and most double-mutant combinations. Zeins in these extracts were fractionated by reversed-phase highperformance liquid chromatography (RP-HPLC) into 22–24 peaks. Of the resulting 22 major peaks the areas of 16 (per milligram endosperm) were significantly affected by individual mutant genes relative to the zein composition of the normal inbred. In combination these genes exhibited significant epistatic interactions in regulating the expression of individual A/B zeins. Epistatic interactions were judged to be significant when the amount of a peak in a double mutant differed from the averages for the peak in the two respective single mutants. The o2 gene, alone and in combination with other mutant genes, significantly decreased the amounts of many individual zeins. The effect of the o2 gene was the greatest of all the genes examined. Various clustering techniques were used to see if mutant effects could be grouped; among these was principal component analysis, a multivariate statistical technique that analyzes all peak sizes simultaneously. Three-dimensional scatter graphs were constructed based on the first three principal components. For the single mutants, these showed no relationships to gene actions; for the double mutants, however, this technique showed that four single mutants, o2, sh1, su1 and su2, had the greatest effects on zein composition when combined with each other and with the remaining six single mutants.Presented at the XVI International Congress of Genetics, Toronto, Canada, August 20–27, 1988. The mention of firm names or trade products does not imply that they are endorsed or recommended by the USDA over other brands or similar products not mentioned 相似文献