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Stabilized Double-Stranded RNA Strategy Improves Cotton Resistance to CBW ( Anthonomus grandis). Int J Mol Sci 2022; 23:ijms232213713. [PMID: 36430188 PMCID: PMC9691246 DOI: 10.3390/ijms232213713] [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: 06/30/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 11/11/2022] Open
Abstract
Cotton is the most important crop for fiber production worldwide. However, the cotton boll weevil (CBW) is an insect pest that causes significant economic losses in infested areas. Current control methods are costly, inefficient, and environmentally hazardous. Herein, we generated transgenic cotton lines expressing double-stranded RNA (dsRNA) molecules to trigger RNA interference-mediated gene silencing in CBW. Thus, we targeted three essential genes coding for chitin synthase 2, vitellogenin, and ecdysis-triggering hormone receptor. The stability of expressed dsRNAs was improved by designing a structured RNA based on a viroid genome architecture. We transformed cotton embryos by inserting a promoter-driven expression cassette that overexpressed the dsRNA into flower buds. The transgenic cotton plants were characterized, and positive PCR transformed events were detected with an average heritability of 80%. Expression of dsRNAs was confirmed in floral buds by RT-qPCR, and the T1 cotton plant generation was challenged with fertilized CBW females. After 30 days, data showed high mortality (around 70%) in oviposited yolks. In adult insects fed on transgenic lines, chitin synthase II and vitellogenin showed reduced expression in larvae and adults, respectively. Developmental delays and abnormalities were also observed in these individuals. Our data remark on the potential of transgenic cotton based on a viroid-structured dsRNA to control CBW.
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Cai YM, Dudley QM, Patron NJ. Measurement of Transgene Copy Number in Plants Using Droplet Digital PCR. Bio Protoc 2021; 11:e4075. [PMID: 34327272 PMCID: PMC8292117 DOI: 10.21769/bioprotoc.4075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/25/2021] [Accepted: 03/30/2021] [Indexed: 11/02/2022] Open
Abstract
Transgenic plants are produced both to investigate gene function and to confer desirable traits into crops. Transgene copy number is known to influence expression levels, and consequently, phenotypes. Similarly, knowledge of transgene zygosity is desirable for making quantitative assessments of phenotype and tracking the inheritance of transgenes in progeny generations. Since the first transgenic plants were produced, several methods for determining copy number have been applied, including Southern blotting, quantitative real-time PCR, and more recently, sequencing methods; however, each method has specific disadvantages, compromising throughput, accuracy, or expense. Digital PCR (dPCR) divides reactions into partitions, converting the exponential, analogue nature of PCR into a linear, digital signal that allows the frequency of occurrence of specific sequences to be accurately estimated. Confidence increases with the number of partitions; therefore, the availability of emulsion technologies that enable reactions to be divided into tens of thousands of nanodroplets allows accurate determination of copy number in what has become known as digital droplet PCR (ddPCR). ddPCR offers similar benefits of low costs and scalability as other PCR techniques but with superior accuracy and reliability. Graphic abstract: Digital PCR (dPCR) divides reactions into partitions, converting the exponential, analogue nature of PCR into a linear, digital signal that allows the frequency of transgene copy number to be accurately assessed.
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Affiliation(s)
- Yao-Min Cai
- Earlham Institute, Norwich Research Park, Colney lane, Norwich, UK
| | | | - Nicola J. Patron
- Earlham Institute, Norwich Research Park, Colney lane, Norwich, UK
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Paes de Melo B, Lourenço-Tessutti IT, Morgante CV, Santos NC, Pinheiro LB, de Jesus Lins CB, Silva MCM, Macedo LLP, Fontes EPB, Grossi-de-Sa MF. Soybean Embryonic Axis Transformation: Combining Biolistic and Agrobacterium-Mediated Protocols to Overcome Typical Complications of In Vitro Plant Regeneration. FRONTIERS IN PLANT SCIENCE 2020; 11:1228. [PMID: 32903423 PMCID: PMC7434976 DOI: 10.3389/fpls.2020.01228] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 07/27/2020] [Indexed: 05/09/2023]
Abstract
The first successful attempt to generate genetically modified plants expressing a transgene was preformed via T-DNA-based gene transfer employing Agrobacterium tumefaciens-mediated genetic transformation. Limitations over infectivity and in vitro tissue culture led to the development of other DNA delivery systems, such as the biolistic method. Herein, we developed a new one-step protocol for transgenic soybean recovery by combining the two different transformation methods. This protocol comprises the following steps: agrobacterial preparation, seed sterilization, soybean embryo excision, shoot-cell injury by tungsten-microparticle bombardment, A. tumefaciens-mediated transformation, embryo co-cultivation in vitro, and selection of transgenic plants. This protocol can be completed in approximately 30-40 weeks. The average efficiency of producing transgenic soybean germlines using this protocol was 9.84%, similar to other previously described protocols. However, we introduced a more cost-effective, more straightforward and shorter methodology for transgenic plant recovery, which allows co-cultivation and plant regeneration in a single step, decreasing the chances of contamination and making the manipulation easier. Finally, as a hallmark, our protocol does not generate plant chimeras, in contrast to traditional plant regeneration protocols applied in other Agrobacterium-mediated transformation methods. Therefore, this new approach of plant transformation is applicable for studies of gene function and the production of transgenic cultivars carrying different traits for precision-breeding programs.
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Affiliation(s)
- Bruno Paes de Melo
- Biochemistry and Molecular Biology Department, Universidade Federal de Viçosa (UFV), Viçosa, Brazil
- Embrapa Genetic Resources and Biotechnology, Brasilia, Brazil
- National Institute of Science and Technology in Plant-Pest Interactions (INCTIPP), BIOAGRO, Viçosa, Brazil
- National Institute of Science and Technology, INCT PlantStress Biotech, EMBRAPA, Brasilia, Brazil
| | - Isabela Tristan Lourenço-Tessutti
- Embrapa Genetic Resources and Biotechnology, Brasilia, Brazil
- National Institute of Science and Technology, INCT PlantStress Biotech, EMBRAPA, Brasilia, Brazil
| | - Carolina Vianna Morgante
- Embrapa Genetic Resources and Biotechnology, Brasilia, Brazil
- National Institute of Science and Technology, INCT PlantStress Biotech, EMBRAPA, Brasilia, Brazil
| | - Naiara Cordeiro Santos
- Embrapa Genetic Resources and Biotechnology, Brasilia, Brazil
- National Institute of Science and Technology, INCT PlantStress Biotech, EMBRAPA, Brasilia, Brazil
| | - Luanna Bezerra Pinheiro
- Embrapa Genetic Resources and Biotechnology, Brasilia, Brazil
- National Institute of Science and Technology, INCT PlantStress Biotech, EMBRAPA, Brasilia, Brazil
- Genomic Sciences and Biotechnology PPG, Universidade Católica de Brasília (UCB), Brasilia, Brazil
| | - Camila Barrozo de Jesus Lins
- Embrapa Genetic Resources and Biotechnology, Brasilia, Brazil
- National Institute of Science and Technology, INCT PlantStress Biotech, EMBRAPA, Brasilia, Brazil
| | - Maria Cristina Matar Silva
- Embrapa Genetic Resources and Biotechnology, Brasilia, Brazil
- National Institute of Science and Technology, INCT PlantStress Biotech, EMBRAPA, Brasilia, Brazil
| | - Leonardo Lima Pepino Macedo
- Embrapa Genetic Resources and Biotechnology, Brasilia, Brazil
- National Institute of Science and Technology, INCT PlantStress Biotech, EMBRAPA, Brasilia, Brazil
| | - Elizabeth Pacheco Batista Fontes
- Biochemistry and Molecular Biology Department, Universidade Federal de Viçosa (UFV), Viçosa, Brazil
- National Institute of Science and Technology in Plant-Pest Interactions (INCTIPP), BIOAGRO, Viçosa, Brazil
| | - Maria Fatima Grossi-de-Sa
- Embrapa Genetic Resources and Biotechnology, Brasilia, Brazil
- National Institute of Science and Technology, INCT PlantStress Biotech, EMBRAPA, Brasilia, Brazil
- Genomic Sciences and Biotechnology PPG, Universidade Católica de Brasília (UCB), Brasilia, Brazil
- *Correspondence: Maria Fatima Grossi-de-Sa,
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Relative Expression Analysis of Target Genes by Using Reverse Transcription-Quantitative PCR. Methods Mol Biol 2019. [PMID: 31541438 DOI: 10.1007/978-1-4939-9865-4_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Real-time PCR is a powerful technique used for quantification of defined nucleic acid sequences. Numerous applications of this method have been described including: gene expression studies, diagnosis of pathogens, and detection of genetically modified organisms or mutations. Here, we describe a simple and efficient protocol to determine gene expression in cereals, based on real-time PCR using SYBR® Green dye. This technique provide an inexpensive alternative, since no probes are required, allowing for the quantification of a high number of genes with reduced cost.
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