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Ye X, Shrawat A, Williams E, Rivlin A, Vaghchhipawala Z, Moeller L, Kumpf J, Subbarao S, Martinell B, Armstrong C, Saltarikos MA, Somers D, Chen Y. Commercial scale genetic transformation of mature seed embryo explants in maize. FRONTIERS IN PLANT SCIENCE 2022; 13:1056190. [PMID: 36523626 PMCID: PMC9745677 DOI: 10.3389/fpls.2022.1056190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/07/2022] [Indexed: 06/17/2023]
Abstract
A novel, efficient maize genetic transformation system was developed using Agrobacterium-mediated transformation of embryo explants from mature seeds. Seeds from field grown plants were sterilized and crushed to isolate embryo explants consisting of the coleoptile, leaf primordia, and shoot apical meristem which were then purified from the ground seed bulk preparation. The infection of relevant tissues of seed embryo explants (SEEs) by Agrobacterium was improved by the centrifugation of the explants. Transgenic plants were obtained by multiple bud induction on high cytokinin media, followed by plant regeneration on hormone-free medium. Three different selectable markers (cp4 epsps, aadA, and nptII) were successfully used for producing transgenic plants. Stable integration of transgenes in the maize genome was demonstrated by molecular analyses and germline transmission of the inserted transgenes to the next generation was confirmed by pollen segregation and progeny analysis. Phenotypic evidence for chimeric transgenic tissue was frequently observed in initial experiments but was significantly reduced by including a second bud induction step with optimized cytokinin concentration. Additional improvements, including culturing explants at an elevated temperature during bud induction led to the development of a revolutionary system for efficient transgenic plant production and genome editing. To our knowledge, this is the first report of successful transgenic plant regeneration through Agrobacterium-mediated transformation of maize mature SEEs. This system starts with mature seed that can be produced in large volumes and the SEEs explants are storable. It has significant advantages in terms of scalability and flexibility over methods that rely on immature explants.
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Affiliation(s)
- Xudong Ye
- Plant Biotechnology, Bayer Crop Science, W. St. Louis, MO, United States
| | - Ashok Shrawat
- Plant Biotechnology, Bayer Crop Science, W. St. Louis, MO, United States
| | - Edward Williams
- Agracetus Campus, Monsanto Company, Middleton, WI, United States
| | - Anatoly Rivlin
- Agracetus Campus, Monsanto Company, Middleton, WI, United States
| | | | - Lorena Moeller
- Plant Biotechnology, Bayer Crop Science, W. St. Louis, MO, United States
| | - Jennifer Kumpf
- Mystic Research, Monsanto Company, Mystic, CT, United States
| | - Shubha Subbarao
- Plant Biotechnology, Bayer Crop Science, W. St. Louis, MO, United States
| | - Brian Martinell
- Plant Biotechnology, Bayer Crop Science, W. St. Louis, MO, United States
| | - Charles Armstrong
- Plant Biotechnology, Bayer Crop Science, W. St. Louis, MO, United States
| | | | - David Somers
- Mystic Research, Monsanto Company, Mystic, CT, United States
| | - Yurong Chen
- Plant Biotechnology, Bayer Crop Science, W. St. Louis, MO, United States
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Raldugina GN, Hoang TZ, Ngoc HB, Karpichev IV. An increased proportion of transgenic plants in the progeny of rapeseed (Brassica napus L.) transformants. Vavilovskii Zhurnal Genet Selektsii 2021; 25:147-156. [PMID: 34901712 PMCID: PMC8627876 DOI: 10.18699/vj21.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/23/2021] [Accepted: 01/27/2021] [Indexed: 11/20/2022] Open
Abstract
Cotyledon and leaf explants of two spring rapeseed varieties were transformed with Agrobacterium
tumefaciens harboring a genetic construct with the gfp marker gene. In order to reduce the proportion of hyperhydrated shoots, which appeared during regenerant formation, we optimized sucrose content in the regeneration media. Analysis of the progeny obtained from T0 regenerants showed that in a number of lines the distribution of the gfp marker did not follow Mendelian segregation of a monogenic trait in self-pollinated plants, while in
the progeny of the other lines of transgenic plants, the gfp marker was completely absent, although its presence
had been confirmed in all selected T0 plants. We also found that in individual transformants gfp is randomly
inherited throughout the central peduncle; its presence in the genome of seedlings does not depend on the location of the pod. Thus, both transformed and non-transformed cells were involved in the formation of gametes in
T0 plants. In addition, marker segregation was different in plants of the T1 line obtained by nodal cuttings of a
primary transformant, depending on the location of the cuttings on the stem of the original plant, indicating that
the nature of T1 generation plants was also chimeric. Furthermore, we showed that propagation of plants by cutting followed by propagation by seeds formed as a result of self-pollination led to an increase in the proportion
of transgenic plants in subsequent generations. The results obtained during the course of this study show that
the transformants were chimeric, i. e. their tissues contained both transgenic and non-transgenic cells, and this
chimeric nature was passed on to subsequent generations. We found that, in addition to nutrient media composition, other factors such as plant genotype and explant type also contribute to the rising of chimeric plants during
transformation. Based on these results, we developed a simplified method, which consists of several rounds of a
combination of cutting, seed production by self-pollination, and subsequent culling of wild-type plants, which
significantly enriched descendent populations of the original rapeseed transformants with plants transgenic for
the gfp marker
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Affiliation(s)
- G N Raldugina
- Timiryazev Institute of Plant Physiology of the Russian Academy of Sciences, Moscow, Russia
| | - T Z Hoang
- Timiryazev Institute of Plant Physiology of the Russian Academy of Sciences, Moscow, Russia NKLPCB, Agricultural Genetics Institute, Hanoi, Vietnam
| | - H B Ngoc
- Timiryazev Institute of Plant Physiology of the Russian Academy of Sciences, Moscow, Russia
| | - I V Karpichev
- Timiryazev Institute of Plant Physiology of the Russian Academy of Sciences, Moscow, Russia
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Wilms H, De Bièvre D, Longin K, Swennen R, Rhee J, Panis B. Development of the first axillary in vitro shoot multiplication protocol for coconut palms. Sci Rep 2021; 11:18367. [PMID: 34526563 PMCID: PMC8443624 DOI: 10.1038/s41598-021-97718-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 08/02/2021] [Indexed: 11/24/2022] Open
Abstract
The coconut palm or "tree of life" is one of nature's most useful plants and the demand for its fruit is increasing. However, coconut production is threatened by ageing plantations, pests and diseases. Currently, the palm is exclusively propagated via seeds, limiting the amount of planting material. A novel micropropagation method is presented, based on axillary shoot formation. Apical meristems of in vitro coconut seedlings are cultured onto Y3 medium containing 1 µM TDZ. This induces the apical meristem to proliferate through axillary shoots in ~ 27% of the initiated explants. These axillary shoots are seen as white clumps of proliferating tissue and can be multiplied at a large scale or regenerated into rooted in vitro plantlets. This innovative micropropagation method will enable the production of disease-free, high quality in vitro plantlets, which will solve the worldwide scarcity of coconut planting material.
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Affiliation(s)
- Hannes Wilms
- Laboratory of Tropical Crop Improvement, Biosystems, KU Leuven, Leuven, Belgium
| | - Dries De Bièvre
- Laboratory of Tropical Crop Improvement, Biosystems, KU Leuven, Leuven, Belgium
| | - Kevin Longin
- Laboratory of Tropical Crop Improvement, Biosystems, KU Leuven, Leuven, Belgium
| | - Rony Swennen
- Laboratory of Tropical Crop Improvement, Biosystems, KU Leuven, Leuven, Belgium
- International Institute of Tropical Agriculture, Plot 15B Naguru East Road, Upper Naguru, Box 7878, Kampala, Uganda
| | - Juhee Rhee
- National Agrobiodiversity Center, RDA, Jeonju, Korea
| | - Bart Panis
- Laboratory of Tropical Crop Improvement, Biosystems, KU Leuven, Leuven, Belgium.
- Bioversity International, Belgian Office at KU Leuven, Leuven, Belgium.
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Das Bhowmik SS, Cheng AY, Long H, Tan GZH, Hoang TML, Karbaschi MR, Williams B, Higgins TJV, Mundree SG. Robust Genetic Transformation System to Obtain Non-chimeric Transgenic Chickpea. FRONTIERS IN PLANT SCIENCE 2019; 10:524. [PMID: 31105725 PMCID: PMC6498970 DOI: 10.3389/fpls.2019.00524] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Accepted: 04/04/2019] [Indexed: 05/30/2023]
Abstract
Chickpea transformation is an important component for the genetic improvement of this crop, achieved through modern biotechnological approaches. However, recalcitrant tissue cultures and occasional chimerism, encountered during transformation, hinder the efficient generation of transgenic chickpeas. Two key parameters, namely micro-injury and light emitting diode (LED)-based lighting were used to increase transformation efficiency. Early PCR confirmation of positive in vitro transgenic shoots, together with efficient grafting and an extended acclimatization procedure contributed to the rapid generation of transgenic plants. High intensity LED light facilitate chickpea plants to complete their life cycle within 9 weeks thus enabling up to two generations of stable transgenic chickpea lines within 8 months. The method was validated with several genes from different sources, either as single or multi-gene cassettes. Stable transgenic chickpea lines containing GUS (uidA), stress tolerance (AtBAG4 and TlBAG), as well as Fe-biofortification (OsNAS2 and CaNAS2) genes have successfully been produced.
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Affiliation(s)
| | - Alam Yen Cheng
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Hao Long
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Grace Zi Hao Tan
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Thi My Linh Hoang
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Mohammad Reza Karbaschi
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Brett Williams
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Thomas Joseph V. Higgins
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
- CSIRO Agriculture and Food, Canberra, ACT, Australia
| | - Sagadevan G. Mundree
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
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Das Bhowmik SS, Cheng AY, Long H, Tan GZH, Hoang TML, Karbaschi MR, Williams B, Higgins TJV, Mundree SG. Robust Genetic Transformation System to Obtain Non-chimeric Transgenic Chickpea. FRONTIERS IN PLANT SCIENCE 2019; 10:524. [PMID: 31105725 DOI: 10.3389/fpls.2019.00524/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Accepted: 04/04/2019] [Indexed: 05/20/2023]
Abstract
Chickpea transformation is an important component for the genetic improvement of this crop, achieved through modern biotechnological approaches. However, recalcitrant tissue cultures and occasional chimerism, encountered during transformation, hinder the efficient generation of transgenic chickpeas. Two key parameters, namely micro-injury and light emitting diode (LED)-based lighting were used to increase transformation efficiency. Early PCR confirmation of positive in vitro transgenic shoots, together with efficient grafting and an extended acclimatization procedure contributed to the rapid generation of transgenic plants. High intensity LED light facilitate chickpea plants to complete their life cycle within 9 weeks thus enabling up to two generations of stable transgenic chickpea lines within 8 months. The method was validated with several genes from different sources, either as single or multi-gene cassettes. Stable transgenic chickpea lines containing GUS (uidA), stress tolerance (AtBAG4 and TlBAG), as well as Fe-biofortification (OsNAS2 and CaNAS2) genes have successfully been produced.
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Affiliation(s)
| | - Alam Yen Cheng
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Hao Long
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Grace Zi Hao Tan
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Thi My Linh Hoang
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Mohammad Reza Karbaschi
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Brett Williams
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Thomas Joseph V Higgins
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
- CSIRO Agriculture and Food, Canberra, ACT, Australia
| | - Sagadevan G Mundree
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
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McCormick S. Altered phenotypes via graft-transmitted siRNAs. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:3-4. [PMID: 30240544 DOI: 10.1111/tpj.14082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
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Yu N, Cao L, Yuan L, Zhi X, Chen Y, Gan S, Chen L. Maintenance of grafting-induced epigenetic variations in the asexual progeny of Brassica oleracea and B. juncea chimera. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:22-38. [PMID: 30086201 DOI: 10.1111/tpj.14058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/23/2018] [Accepted: 07/31/2018] [Indexed: 05/19/2023]
Abstract
Grafting-induced variations have been observed in many plant species, but the heritability of variation in progeny is not well understood. In our study, adventitious shoots from the C cell lineage of shoot apical meristem (SAM) grafting chimera TCC (where the origin of the outmost, middle and innermost cell layers, respectively, of SAM is designated by 'T' for tuber mustard and 'C' for red cabbage) were induced and identified as r-CCC (r = regenerated). To investigate the maintenance of grafting variations during cell propagation and regeneration, different generations of asexual progeny (r-CCCn, n = generation) were established through successive regeneration of axillary shoots from r-CCC. The fourth generation of r-CCC (r-CCC4) was selected to perform whole genome bisulfite sequencing for comparative analysis of hetero-grafting-induced global methylation changes relative to r-s-CCC4 (s = self-grafting). Increased CHH methylation levels and proportions were observed in r-CCC4, with substantial changes occurring in the repeat elements. Small RNA sequencing revealed 1135 specific small interfering RNA (siRNA) tags that were typically expressed in r-CCC, r-CCC2 and r-CCC4. Notably, 65% of these specific siRNAs were associated with repeat elements, termed RE siRNAs. Subsequent analysis revealed that the CHH methylation of RE siRNA-overlapping regions was mainly hypermethylation in r-CCC4, indicating that they were responsible for directing and maintaining grafting-induced CHH methylation. Moreover, the expression of 13 differentially methylated genes (DMGs) correlated with the phenotypic variation, showing differential expression levels between r-CCC4 and r-s-CCC4. These DMGs were predominantly CG hypermethylated, their methylation modifications corresponded to the transcription of relative methyltransferase.
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Affiliation(s)
- Ningning Yu
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Liwen Cao
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Lu Yuan
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Xiao Zhi
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Yiqian Chen
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Susheng Gan
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Liping Chen
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
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Li J, Wang Y, Zhang L, Liu B, Cao L, Qi Z, Chen L. Heritable variation and small RNAs in the progeny of chimeras of Brassica juncea and Brassica oleracea. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:4851-62. [PMID: 24006424 PMCID: PMC3830474 DOI: 10.1093/jxb/ert266] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Chimeras have been used to study the transmission of genetic material and the resulting genetic variation. In this study, two chimeras, TCC and TTC (where the origin of the outer, middle, and inner cell layers, respectively, of the shoot apical meristem is designated by a 'T' for tuber mustard and 'C' for red cabbage), as well as their asexual and sexual progeny, were used to analyse the mechanism and the inheritance of the variation induced by grafting. Asexual TCC progeny were obtained by adventitious shoot regeneration, while TTC sexual progeny were produced by self-crossing. This study observed similar morphological variations in both the asexual and sexual progeny, including changes in leaf shape and the pattern of shoot apical meristem termination. The leaf shape variation was stable, while the rate of shoot apical meristem termination in the TTC progenies decreased from 74.52% to 3.01% after three successive rounds of self-crossing. Specific red cabbage small RNAs were found in the asexually regenerated plants (rTTT) that were not present in TTT, indicating that small RNAs might be transmitted from red cabbage to tuber mustard during grafting. Moreover, in parallel with the variations in phenotype observed in the progeny, some conserved miRNAs were differentially expressed in rTTT and TTT, which correlated with changes in expression of their target genes. These results suggest that the change in small RNA expression induced by grafting may be an important factor for introducing graft-induced genetic variations, providing a basis for further investigating the mechanism of graft-induced genetic variation through epigenetics.
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Affiliation(s)
- Junxing Li
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China
- Key Laboratory of Horticultural Plants Growth, Development and Biotechnology, Agricultural Ministry of China, Hangzhou 310058, PR China
- * These authors contributed equally to this manuscript
| | - Yan Wang
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China
- Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, PR China
- * These authors contributed equally to this manuscript
| | - Langlang Zhang
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China
- Key Laboratory of Horticultural Plants Growth, Development and Biotechnology, Agricultural Ministry of China, Hangzhou 310058, PR China
| | - Bin Liu
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China
- Key Laboratory of Horticultural Plants Growth, Development and Biotechnology, Agricultural Ministry of China, Hangzhou 310058, PR China
| | - Liwen Cao
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China
- Key Laboratory of Horticultural Plants Growth, Development and Biotechnology, Agricultural Ministry of China, Hangzhou 310058, PR China
| | - Zhenyu Qi
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China
- Agriculture Experiment Station, Zhejiang University, Hangzhou 310058, PR China
| | - Liping Chen
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China
- Key Laboratory of Horticultural Plants Growth, Development and Biotechnology, Agricultural Ministry of China, Hangzhou 310058, PR China
- To whom correspondence should be addressed. E-mail:
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Faize M, Faize L, Burgos L. Using quantitative real-time PCR to detect chimeras in transgenic tobacco and apricot and to monitor their dissociation. BMC Biotechnol 2010; 10:53. [PMID: 20637070 PMCID: PMC2912785 DOI: 10.1186/1472-6750-10-53] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 07/16/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The routine generation of transgenic plants involves analysis of transgene integration into the host genome by means of Southern blotting. However, this technique cannot distinguish between uniformly transformed tissues and the presence of a mixture of transgenic and non-transgenic cells in the same tissue. On the other hand, the use of reporter genes often fails to accurately detect chimerical tissues because their expression can be affected by several factors, including gene silencing and plant development. So, new approaches based on the quantification of the amount of the transgene are needed urgently. RESULTS We show here that chimeras are a very frequent phenomenon observed after regenerating transgenic plants. Spatial and temporal analyses of transformed tobacco and apricot plants with a quantitative, real-time PCR amplification of the neomycin phosphotransferase (nptII) transgene as well as of an internal control (beta-actin), used to normalise the amount of target DNA at each reaction, allowed detection of chimeras at unexpected rates. The amount of the nptII transgene differed greatly along with the sub-cultivation period of these plants and was dependent on the localisation of the analysed leaves; being higher in roots and basal leaves, while in the apical leaves it remained at lower levels. These data demonstrate that, unlike the use of the gus marker gene, real-time PCR is a powerful tool for detection of chimeras. Although some authors have proposed a consistent, positive Southern analysis as an alternative methodology for monitoring the dissociation of chimeras, our data show that it does not provide enough proof of uniform transformation. In this work, however, real-time PCR was applied successfully to monitor the dissociation of chimeras in tobacco plants and apricot callus. CONCLUSIONS We have developed a rapid and reliable method to detect and estimate the level of chimeras in transgenic tobacco and apricot plants. This method can be extended to monitor the dissociation of chimeras and the recovery of uniformly-transformed plants.
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Affiliation(s)
- Mohamed Faize
- Laboratoire de Biologie et Biotechnologie Végétales. Faculté des Sciences, Université Chouaib Doukkali, 24000 El Jadida, Morocco
| | - Lydia Faize
- Grupo de Biotecnología, Departamento de Mejora de Frutales. CEBAS-CSIC, P.O. Box 164, 30.100 Murcia, Spain
| | - Lorenzo Burgos
- Grupo de Biotecnología, Departamento de Mejora de Frutales. CEBAS-CSIC, P.O. Box 164, 30.100 Murcia, Spain
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