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1.
Transformation of oat and inheritance of bar gene expression 总被引:2,自引:0,他引:2
Kuai B. Perret S. Wan S. M. Dalton S. J. Bettany A. J. E. Morris P. 《Plant Cell, Tissue and Organ Culture》2001,66(2):79-88
Fertile transgenic plants of oat (Avena sativa L. var. Melys) were produced following microprojectile bombardment of primary embryogenic calli from immature embryos with
two plasmids containing the bar gene or the β-glucuronidase (uidA) gene, after selection with glufosinate ammonium. Eleven plants were regenerated from phosphinothricin resistant callus,
with three of the eleven plants containing either intact or rearranged copies. No plants co-transformed with the non-selected
uidA gene were detected. Stable transmission and expression of the bar gene in the T1 inbred progenies occurred in a Mendelian manner in one line, which contained an intact bar gene, and in all six T2 lines tested from this transformant.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
2.
Comparative analysis of transgenic rice plants obtained by Agrobacterium-mediated transformation and particle bombardment 总被引:5,自引:0,他引:5
Dai Shunhong Zheng Ping Marmey Philippe Zhang Shiping Tian Wenzhong Chen Shouyi Beachy Roger N. Fauquet Claude 《Molecular breeding : new strategies in plant improvement》2001,7(1):25-33
We compared rice transgenic plants obtained by Agrobacterium-mediated and particle bombardment transformation by carrying out molecular analyses of the T0, T1 and T2 transgenic plants. Oryza
sativa japonica rice (c.v. Taipei 309) was transformed with a construct (pWNHG) that carried genes coding for neomycin phosphotransferase (nptII), hygromycin phosphotransferase (Hygr), and -glucuronidase (GUS). Thirteen and fourteen transgenic lines produced via either method were selected and subjected to molecular analysis. Based on our data, we could draw the following conclusions. Average gene copy numbers of the three transgenes were 1.8 and 2.7 for transgenic plants obtained by Agrobacterium and by particle bombardment, respectively. The percentage of transgenic plants containing intact copies of foreign genes, especially non-selection genes, was higher for Agrobacterium-mediated transformation. GUS gene expression level in transgenic plants obtained from Agrobacterium-mediated transformation was more stable overall the transgenic plant lines obtained by particle bombardment. Most of the transgenic plants obtained from the two transformation systems gave a Mendelian segregation pattern of foreign genes in T1 and T2 generations. Co-segregation was observed for lines obtained from particle bombardment, however, that was not always the case for T1 lines obtained from Agrobacterium-mediated transformation. Fertility of transgenic plants obtained from Agrobacterium-mediated transformation was better. In summary, the Agrobacterium-mediated transformation is a good system to obtain transgenic plants with lower copy number, intact foreign gene and stable gene expression, while particle bombardment is a high efficiency system to produce large number of transgenic plants with a wide range of gene expression. 相似文献
3.
Transformation of maize using microprojectile bombardment: An update and perspective 总被引:1,自引:0,他引:1
W. J. Gordon-Kamm T. M. Spencer J. V. O’Brien W. G. Start R. J. Daines T. R. Adams M. L. Mangano S. A. Chambers S. J. Zachwieja N. G. Willetts W. R. Adams Jr. C. J. Mackey R. W. Krueger A. P. Kausch P. G. Lemaux 《In vitro cellular & developmental biology. Plant》1991,27(1):21-27
Summary Using microprojectile bombardment of maize suspension cultures and bialaphos selection, transformed embryogenic calli have
been recovered in numerous independent experiments. Fertile transgenic plants have been regenerated from several transformed
callus lines. Stable inheritance and expression ofbar and functional activity of the enzyme phosphinothricin acetyl transferase were observed in three subsequent generations of
transformed plants. Evidence to date indicates that the transformation process and the presence of the foreign gene per se
do not detrimentally influence either plant vigor or fertility. This represents a practical method for introducing foreign
genes into maize, which may be applicable to other monocot species.
Presented in the Session-in-Depth Genetic Transformation and Genetic Analysis Using Microprojectile Bombardment at the Annual
Meeting of the Tissue Culture Association, Houston, Texas, June 10–13, 1990. 相似文献
4.
Production of transgenic maize plants and progeny by bombardment of hi-II immature embryos 总被引:4,自引:0,他引:4
D. D. Songstad C. L. Armstrong W. L. Petersen B. Hairston M. A. W. Hinchee 《In vitro cellular & developmental biology. Plant》1996,32(3):179-183
Summary Production of transgenic maize (Zea mays L.) callus, plants, and progeny from microprojectile bombardment of 2–5-d cultured Hi-II immature embryos is described. Histological
evidence indicates that these tissues are amenable to transformation due to surface layer cell division of the scutellum.
Two out of every 100 bombarded embryos produced transgenic callus and R0 transgenic plants were both male and female fertile. Expected segregation of transgenes was observed in progeny. The primary
advantage of bombarding these tissues is increased male and female fertility of transgenic plants compared with those produced
using long-term callus or suspension cultures. 相似文献
5.
Transgenic doubled haploid rapeseed (Brassica napus L. cvs. Global and PF704) plants were obtained from microspore-derived embryo (MDE) hypocotyls using the microprojectile bombardment. The binary vector
pCAMBIA3301 containing the gus and bar genes under control of CaMV 35S promoter was used for bombardment experiments. Transformed plantlets were selected and continuously
maintained on selective medium containing 10 mg l−1 phosphinothricin (PPT) and transgenic plants were obtained by selecting transformed secondary embryos. The presence, copy
numbers and expression of the transgenes were confirmed by PCR, Southern blot, RT-PCR and histochemical GUS analyses. In progeny
test, three out of four primary transformants for bar gene produced homozygous lines. The ploidy level of transformed plants was confirmed by flow cytometery analysis before colchicine
treatment. All of the regenerated plants were haploid except one that was spontaneous diploid. High frequency of transgenic
doubled haploid rapeseeds (about 15.55% for bar gene and 11.11% for gus gene) were considerably produced after colchicines treatment of the haploid plantlets. This result show a remarkable increase
in production of transgenic doubled haploid rapeseed plants compared to previous studies. 相似文献
6.
Use of bar as a selectable marker gene and for the production of herbicide-resistant rice plants from protoplasts 总被引:26,自引:0,他引:26
We have used the bar gene in combination with the herbicide Basta to select transformed rice (Oryza sativa L. cv. Radon) protoplasts for the production of herbicide-resistant rice plants. Protoplasts, obtained from regenerable suspension cultures established from immature embryo callus, were transformed using PEG-mediated DNA uptake. Transformed calli could be selected 2–4 weeks after placing the protoplast-derived calli on medium containing the selective agent, phosphinothricin (PPT), the active component of Basta. Calli resistant to PPT were capable of regenerating plants. Phosphinothricin acetyltransferase (PAT) assays confirmed the expression of the bar gene in plants obtained from PPT-resistant calli. The only exceptions were two plants obtained from the same callus that had multiple copies of the bar gene integrated into their genomes. The transgenic status of the plants was varified by Southern blot analysis. In our system, where the transformation was done via the protoplast method, there were very few escapes. The efficiency of co-transformation with a reporter gene gusA, was 30%. The To plants of Radon were self-fertile. Both the bar and gusA genes were transmitted to progeny as confirmed by Southern analysis. Both genes were expressed in T1 and T2 progenies. Enzyme analyses on T1 progeny plants also showed a gene dose response reflecting their homozygous and heterozygous status. The leaves of To plants and that of the progeny having the bar gene were resistant to application of Basta. Thus, the bar gene has proven to be a useful selectable and screenable marker for the transformation of rice plants and for the production of herbicide-resistant plants. 相似文献
7.
High-efficiency,microprojectile-mediated cotransformation of sugarcane,using visible or selectable markers 总被引:3,自引:0,他引:3
Robert Bower Adrian R. Elliott Bernard A. M. Potier Robert G. Birch 《Molecular breeding : new strategies in plant improvement》1996,2(3):239-249
Transient expression of the maize anthocyanin regulatory elements,R andC1, was used to optimise parameters for microprojectile-mediated delivery of DNA into sugarcane embryogenic callus. Osmotic treatment of target tissues and particle acceleration in a high-pressure helium pulse increased the frequency of transient expression to 5–8×103 cells per bombardment, with minimal tissue damage. An average of 0.34% of transiently expressing cells developed into stably transformed, anthocyanin-pigmented proembryoids which subsequently regenerated into plantlets. However, constitutive expression ofR andC1 proved deleterious, and no anthocyanin-pigmented plant survived beyond 3 cm in height. We also compared selective subculture of callus portions showing luciferase activity with antibiotic selection on medium containing G418 or phosphinothricin, upon bombardment of callus with constructs driving strong expression ofluc, aphA orbar genes. Selective subculture based on luciferase activity enabled recovery of 1.4±0.5 independent transgenic plants per bombardment, compared to 19.8±3.7 independent transgenic plants per bombardment from an optimised G418 selection regimen, and no transformed plants from phosphinothricin selection. Whenluc andaphA on separate plasmids were coprecipitated onto microprojectiles before bombardment, 67–79% of callus lines selected for G418 resistance also showed luciferase activity detectable under a low-light camera. Southern analysis confirmed a very high cotransformation frequency, with variable copy numbers of introduced genes. The high efficiencies of gene transfer, selection and cotransformation in the optimised system, coupled with the simple initiation and regeneration of embryogenic callus, provide an effective tool for practical genetic transformation of sugarcane. 相似文献
8.
M.-J. Cho H. W. Choi B. B. Buchanan P. G. Lemaux 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,98(8):1253-1262
Barley (Hordeum vulgare L.) hordeins are alcohol-soluble redundant storage proteins that accumulate in protein bodies of the starchy endosperm during
seed development. Strong endosperm-specific β-glucuronidase gene-(uidA; gus) expression driven by B1- and D-hordein promoters was observed in stably transformed barley plants co-transformed with the selectable herbicide resistance
gene, bar. PCR analysis using DNA from calli of 22 different lines transformed with B1- or D-hordein promoter-uidA fusions showed the expected 1.8-kb uidA fragment after PCR amplification. DNA-blot analysis of genomic DNA from T0 leaf tissue of 13 lines showed that 12 (11 independent) lines produced uidA fragments and that one line was uidA-negative. T1 progeny from 6 out of 12 independent regenerable transgenic lines tested for uidA expression showed a 3 : 1 segregation pattern. Of the remaining six transgenic lines, one showed a segregation ratio of 15 : 1
for GUS, one expressed bar alone, one lacked transmission of either gene to T1 progeny, and three were sterile. Stable GUS expression driven by the hordein promoters was observed in T5 progeny in one line, T4 progeny in one line, T3 progeny in three lines and T2 or T1 progeny in the remaining two fertile lines tested; homozygous transgenic plants were obtained from three lines. In the homozygous
lines the expression of the GUS protein, driven by either the B1- or D-hordein promoters, was highly expressed in endosperm at early to mid-maturation stages. Expression of bar driven by the maize ubiquitin promoter was also stably transmitted to T1 progeny in seven out of eight lines tested. However, in most lines PAT expression driven by the maize ubiquitin promoter
was gradually lost in T2 or later generations; one homozygous line was obtained. In contrast, six out of seven lines stably expressed GUS driven by
the hordein promoters in T2 or later generations. We conclude that the B1- and D-hordein promoters can be used to engineer, and subsequently study, stable endosperm-specific gene expression in barley
and potentially to modify barley seeds through genetic engineering.
Received: 28 May 1998 / Accepted: 19 December 1998 相似文献
9.
Production of fertile transgenic maize plants by silicon carbide whisker-mediated transformation 总被引:10,自引:1,他引:9
Bronwyn R. Frame Paul R. Drayton Susan V. Bagnall Carol J. Lewnau W. Paul Bullock H. Martin Wilson James M. Dunwell John A. Thompson Kan Wang 《The Plant journal : for cell and molecular biology》1994,6(6):941-948
A simple and inexpensive system for the generation of fertile, transgenic maize plants has been developed. Cells from embryogenic maize suspension cultures were transformed using silicon carbide whiskers to deliver plasmid DNA carrying the bacterial bar and uidA (gus) genes. Transformed cells were selected on medium containing the herbicide bialaphos. Integration of the bar gene and activity of the enzyme phosphinothricin acetyl transferase (PAT) were confirmed in all bialaphos-resistant callus lines analysed. Fertile transgenic maize plants were regenerated. Herbicide spraying of progeny plants revealed that the bar gene was transmitted in a Mendelian fashion. 相似文献
10.
This paper reports on the successful Agrobacterium-mediated transformation of oat, and on some factors influencing this process. In the first step of the experiments, three
cultivars, two types of explant, and three combinations of strain/vectors, which were successfully used for transformation
of other cereals were tested. Transgenic plants were obtained from the immature embryos of cvs. Bajka, Slawko and Akt and
from leaf base explants of cv. Bajka after transformation with A. thumefaciens strain LBA4404(pTOK233). The highest transformation rate (12.3%) was obtained for immature embryos of cv. Bajka. About 79%
of the selected plants proved to be transgenic; however, only 14.3% of the T0 plants and 27.5% of the T1 showed GUS expression. Cell competence of both types of explant differed in terms of their transformation ability and transgene
expression. The next step of the study was to test the suitability for oat transformation of the pGreen binary vector combined
with different selection cassettes: nptII or bar under the nos or 35S promoter. Transgenic plants were selected in combinations transformed with nos::nptII, 35S::nptII and nos::bar. The highest transformation efficiency (5.3%) was obtained for cv. Akt transformed with nos::nptII. A detailed analysis of the T0 plants selected from a given callus line and their progeny revealed that they were the mixture of transgenic, chimeric-transgenic
and non-transgenic individuals. Southern blot analysis of T0 and T1 showed simple integration pattern with the low copy number of the introduced transgenes. 相似文献
11.
Asad S Mukhtar Z Nazir F Hashmi JA Mansoor S Zafar Y Arshad M 《Molecular biotechnology》2008,40(2):161-169
A silicon carbide whisker-mediated gene transfer system with recovery of fertile and stable transformants was developed for
cotton (Gossypium hirsutum L.) cv. Coker-312. Two-month-old hypocotyl-derived embryogenic/non-embryogenic calli at different days after subculture were
treated with silicon carbide whiskers for 2 min in order to deliver pGreen0029 encoding GUS gene and pRG229 AVP1 gene, encoding Arabidopsis vacuolar pyrophosphatase, having neomycin phosphotransferaseII (nptII) genes as plant-selectable markers. Three crucial transformation parameters, i.e., callus type, days after subculture and
selection marker concentration for transformation of cotton calli were evaluated for optimum efficiency of cotton embryogenic
callus transformation giving upto 94% transformation efficiency. Within six weeks, emergence of kanamycin-resistant (kmr) callus colonies was noted on selection medium. GUS and Southern blot analysis showed expression of intact and multiple transgene
copies in the transformed tissues. Kanamycin wiping of leaves from T1, T2, and T3 progeny plants revealed that transgenes were inherited in a Mendelian fashion. Salt treatment of T1
AVP1 transgenic cotton plants showed significant enhancement in salt tolerance as compared to control plants. Thus far, this is
first viable physical procedure after particle bombardment available for cotton that successfully can be used to generate
fertile cotton transformants. 相似文献
12.
A. Nadolska-Orczyk A. Przetakiewicz K. Kopera A. Binka W. Orczyk 《Journal of Plant Growth Regulation》2005,24(1):2-10
Transgenic plants of triticale cv. Wanad were obtained after transformation using three combinations of strain/vectors. Two
of them were hypervirulent Agrobacterium tumefaciens strains (AGL1 and EHA101) with vectors containing bar under maize ubiquitin 1 promoter (pDM805), and both hpt under p35S and nptII under pnos (pGAH). The third one was a regular LBA4404 strain containing super-binary plasmid pTOK233 with selection genes
the same as in pGAH. The efficiency of transformation was from 0 to 16% and it was dependent on the selection factor, auxin
pretreatment, and the strain/vector combination. The highest number of transgenic plants was obtained after transformation
with LBA4404(pTOK233) and kanamycin selection. Pretreatment of explants with picloram led to the highest number of plants
obtained after transformation with both Agrobacterium/vector systems LBA4404(pTOK233) and EHA101(pGAH) and selected with kanamycin. Transgenic character of selected plants was
examined by PCR using specific primers for bar, gus, nptII, and hpt and confirmed by Southern blot hybridization analysis. There was no GUS expression in T0 transgenic plants transformed with gus under p35S. However the GUS expression was detectable in the progeny of some lines. Only 30% of 46 transgenic lines showed
Mendelian segregation of GUS expressing to GUS not expressing plants. In the remaining 70% the segregation was non-Mendelian
and the rate was much lower than 3:1. Factors that might effect expression of transgenes in allohexaploid monocot species
are discussed. 相似文献
13.
Transgenic cereal (tritordeum) plants obtained at high efficiency by microprojectile bombardment of inflorescence tissue 总被引:7,自引:0,他引:7
Pilar Barcelo Christine Hagel Dirk Becker Antonio Martin Horst Lörz 《The Plant journal : for cell and molecular biology》1994,5(4):583-592
Transgenic cereal plants expressing the β-glucuronidase (uidA) and neomycin phosphotransferase (neo) genes were obtained via microprojectile bombardment of immature inflorescence tissue of tritordeum (the fertile Hordeum x Triticum amphiploid, HchHchAABB). A total of 17 independent transgenic plants were recovered from 32 bombardments (on average four inflorescences per shot). Of the bombardment and culture parameters tested, explant preculture had the most influence on stable transformation frequency. The uidA and neo genes were supplied on two separate plasmids (co-transformation) and 88% of the transgenic plants recovered expressed both genes. Southern analysis confirmed the results of histochemical GUS and NPT II assays. Transgenic plants were grown to maturity and flowered and set seed. Pollen from four T0 GUS+ plants analysed showed GUS activity and T1 seedlings derived from one of the transgenic plants showed a segregation of 2.75:1 (GUS+:GUS−) for uidA gene activity. 相似文献
14.
Tissue electroporation was applied to a member of the Triticeae family, namely tritordeum (Hordeum chilense Roem.×Triticum turgidum L. Conv. durum), for the generation of fertile transgenic plants. Two transgenic plants were recovered following the treatment of 361 explants
of immature inflorescences (although they were subsequently found to result from the same transformation event). The expression
of both inserted marker genes (uidA and bar) was confirmed using standard assays, while transgene integration was confirmed using PCR and Southern hybridization analyses.
Integration pattern, segregation ratio and the inheritance of transgene expression in T1 progeny were consistent for the presence of a single transgene locus containing five to ten plasmid insertions. Although
this procedure has been applied to other cereal species, stable transformation of the Triticeae using tissue electroporation
has not previously been reported.
Received: 28 October 1999 / Revision received: 25 August 2000 / Accepted: 29 August 2000 相似文献
15.
Development,field evaluation,and agronomic performance of transgenic herbicide resistant rice 总被引:17,自引:0,他引:17
J. H. Oard S. D. Linscombe M. P. Braverman F. Jodari D. C. Blouin M. Leech A. Kohli P. Vain J. C. Cooley P. Christou 《Molecular breeding : new strategies in plant improvement》1996,2(4):359-368
16.
Segregation of transgenes in maize 总被引:23,自引:0,他引:23
T. Michael Spencer James V. O'Brien William G. Start Thomas R. Adams William J. Gordon-Kamm Peggy G. Lemaux 《Plant molecular biology》1992,18(2):201-210
Progeny recovered from backcrossed transgenic maize tissue culture regenerants (R0) were analyzed to determine the segregation, expression, and stability of the introduced genes. Transgenic A188×B73 R0 plants (regenerated from embryogenic suspension culture cells transformed by microprojectile bombardment; see [9]) were pollinated with nontransformed B73 pollen. Inheritance of a selectable marker gene, bar, and a nonselectable marker gene, uidA, was analyzed in progeny (R1) representing four independent transformation events. Activity of the bar gene product, phosphinothricin acetyltransferase (PAT), was assessed in plants comprising the four R1 populations. The number of R1 plants containing PAT activity per total number of R1 plants recovered for each population was 2/7, 19/34, 3/14 and 73/73. Molecular analysis confirmed the segregation of bar in three R1 populations and the lack of segregation in one R1 population. Cosegregation analysis indicated genetic linkage of bar and uidA in all four R1 populations. Analysis of numerous R2 plants derived from crossing transformed R1 plants with nontransformed inbreds revealed 1:1 segregation of PAT activity in three of four lines, including the line that failed to segregate in the R1 generation. Integrated copies of bar in one line appeared to be unstable or poorly transmitted. 相似文献
17.
A comparison of transgenic barley lines produced by particle bombardment and Agrobacterium-mediated techniques 总被引:5,自引:0,他引:5
Two barley transformation systems, Agrobacterium-mediated and particle bombardment, were compared in terms of transformation efficiency, transgene copy number, expression, inheritance and physical structure of the transgenic loci using fluorescence in situ hybridisation (FISH). The efficiency of Agrobacterium-mediated transformation was double that obtained with particle bombardment. While 100% of the Agrobacterium-derived lines integrated between one and three copies of the transgene, 60% of the transgenic lines derived by particle bombardment integrated more than eight copies of the transgene. In most of the Agrobacterium-derived lines, the integrated T-DNA was stable and inherited as a simple Mendelian trait. Transgene silencing was frequently observed in the T1 populations of the bombardment-derived lines. The FISH technique was able to reveal additional details of the transgene integration site. For the efficient production of transgenic barley plants, with stable transgene expression and reduced silencing, the Agrobacterium-mediated method appears to offer significant advantages over particle bombardment. 相似文献
18.
J. Zimny D. Becker R. Brettschneider H. Lörz 《Molecular breeding : new strategies in plant improvement》1995,1(2):155-164
Fertile transgenicTriticale ( ×Triticosecale Wittmack) plants expressing the-glucuronidase (uidA) and phosphinothricin acetyltransferase (bar) genes were obtained after microprojectile bombardment of scutellar tissue with the plasmid pDB1 containing theuidA gene under the control of the actin-1 promoter (Act1) from rice and the selectable marker genebar under the control of the CaMV 35S promoter. From 465 bombarded scutella about 4000 plantlets were regenerated; 300 plants survived the selection. These regenerants were screened for enzyme activity by the histological GUS assay and by spraying the plants with a herbicide (Basta). Twenty-five regenerants showed GUS activity and survived repeated Basta spraying. Southern blot analysis showed the presence of both marker genes introduced into the genome of analysed plants.All transgenic plants were fertile. They were grown to maturity and set seed. Pollen and progeny analyses provided evidence for inheritance of the introduced genes to the next generation. 相似文献
19.
Mature seed‐derived callus from an elite Chinese japonica rice cv. Eyl 105 was transformed with a plasmid containing the selectable marker hygromycin phosphotransferase (hpt) and the reporter β‐glucuronidase (gusA) genes via particle bombardment. After two rounds of selection on hygromycin (30 mg/l)‐containing medium, resistant callus was transferred to hygromycin (30 mg/l)‐containing regeneration medium for plant regeneration. Twenty‐three independent transgenic rice plants were regenerated from 127 bombarded callus with a transformation frequency of 18.1%. All the transgenic plants contained both gusA and hpt genes, revealed by PCR/Southern blot analysis. GUS assay revealed 18 out of 23 plants (78.3%) proliferated on hygromycin‐containing medium had GUS expression at various levels. Genetic analysis confirmed Mendelian segregation of transgenes in progeny. From R2 generations with their R1 parent plants showing 3:1 Mendelian segregation, we identified three independent homozygous transgenic rice lines. The homozygous lines were phenotypically normal and fertile compared to the control plants. We demonstrate that homozygous transgenic rice lines can be obtained via particle bombardment‐mediated transformation and through genetic analysis‐based selection. 相似文献
20.
Transformation of Maize Cells and Regeneration of Fertile Transgenic Plants 总被引:26,自引:0,他引:26 下载免费PDF全文
Gordon-Kamm WJ Spencer TM Mangano ML Adams TR Daines RJ Start WG O'Brien JV Chambers SA Adams WR Willetts NG Rice TB Mackey CJ Krueger RW Kausch AP Lemaux PG 《The Plant cell》1990,2(7):603-618
A reproducible system for the generation of fertile, transgenic maize plants has been developed. Cells from embryogenic maize suspension cultures were transformed with the bacterial gene bar using microprojectile bombardment. Transformed calli were selected from the suspension cultures using the herbicide bialaphos. Integration of bar and activity of the enzyme phosphinothricin acetyltransferase (PAT) encoded by bar were confirmed in all bialaphos-resistant callus lines. Fertile transformed maize plants (R0) were regenerated, and of 53 progeny (R1) tested, 29 had PAT activity. All PAT-positive progeny analyzed contained bar. Localized application of herbicide to leaves of bar-transformed R0 and R1 plants resulted in no necrosis, confirming functional activity of PAT in the transgenic plants. Cotransformation experiments were performed using a mixture of two plasmids, one encoding PAT and one containing the nonselected gene encoding [beta]-glucuronidase. R0 plants regenerated from co-transformed callus expressed both genes. These results describe and confirm the development of a system for introduction of DNA into maize. 相似文献