L.V. is supported by NSF (IOS 1002837)

1. Making the Protoplasts
<ol>
<li>Add 9 mL of 8% mannitol to a Petri dish.</li>
<li>Using a spatula, put 7 day old moss from 2-3 PPNH4 plates of 5- in the Petri dish containing mannitol.</li>
<li>Add 3 mL of 2% Driselase (Sigma D9515-25G) to the Petri dish.</li>
<li>Incubate the Petri dish at room temperature with gentle shaking for 1 hour.</li>
<li>Filter the protoplast suspension through a 100 &mu;m mesh (BD Falcon 352350).</li>
<li>Spin the filtered suspension at 250 g for 5 minutes. Remove the supernatant.</li>
<li>Re-suspend the protoplasts very gently with 500 &mu;L of 8% mannitol.</li>
<li>Add 9.5 mL 8% mannitol in the culture tube. Make sure protoplasts are fully suspended.</li>
<li>Repeat the filtration and re-suspension steps (1.6, 1.7 and 1.8) two more times.</li>
<li>Take 10 &mu;L of the protoplast solution and count the protoplasts in a hemocytometer.</li>
<li>Multiply the number of protoplast in a 16 square area by 10,000 to obtain the number of protoplasts per mL (See Figure 1).</li>
</ol>
2. Transformation
<ol>
<li>Spin the protoplast suspension at 250 g for 5 minutes. Remove the supernatant.</li>
<li>Re-suspend protoplasts in MMg solution at the concentration of 1.6 million protoplasts / mL.</li>
<li>Incubate the protoplast suspension at room temperature for 20 minutes.</li>
<li>Add 600 &mu;L of protoplast suspension into a culture tube containing 60 &mu;g DNA. Swirl the tube gently.</li>
<li>Add 700 &mu;L of PEG/Ca solution into the protoplast / DNA mixture. Swirl the tube gently until whole mixture is homogeneous.</li>
<li>Incubate the mixture at room temperature for 30 minutes.</li>
<li>During this waiting period, cover PRM-B plates with cellophane (80 mm diameter circles, A.A. Packaging Limited, UK); allow cellophane to hydrate on the plate surface for at least 5 min.</li>
<li>With a spatula, remove any air bubbles trapped between the cellophane and the plate.</li>
<li>Dilute the mixture with 3 mL of W5 solution.</li>
<li>Spin the mixture at 250 g for 5 minutes. Remove the supernatant.</li>
<li>Re-suspend protoplasts in melted 2 mL of PRM-T (before adding it to the protoplasts this solution can be kept liquid at 42&deg;C). Plate 1 mL of re-suspend protoplasts per PRM-B plate covered by cellophane. Wrap the plates with Micropore (3M, Health Care). Keep the plates at 25&deg;C in a growth chamber.</li>
<li>Alternatively, protoplasts can be re-suspended in 1 mL of liquid plating medium and plated 0.5 mL on a PRM-B plate covered with cellophane. This allows faster regeneration, but the number of regenerating plants is lower.</li>
<li>Growth chamber is set for a 16 hr. light and 8 hr. dark cycle.</li>
<li>Move the cellophane onto to a fresh selection plate 4 days after transformation.</li>
</ol>
3. Representative Results:
An example of transformation is shown in Figure 2. The DNA used in this example was a supercoiled 7.8 kb plasmid carrying a hygromycin resistant cassette. The amount of protoplasts plated was reduced to 50% for photography. The pictures were taken two weeks after the plants were moved to the selection plates. The transformation efficiency is not affected by the DNA concentration up to 60 &mu;g. Higher concentrations of DNA are detrimental to the efficiency of transformation. The data showed that this method delivers consistent result over a wide range of DNA amounts. This method can also generate stable transformants effectively as shown in Table 1; we can get about 4 stable transformants per microgram of linearized DNA, which is much higher than what was reported previously14.
We also tested the effect of heat shock on transformation efficiency by transforming a supercoiled plasmid carrying a gene for a fluorescent protein as a marker. The heat shock was carried out 10 minutes after room temperature incubation (within Step 2.6) by incubating the mixture in a 45&deg;C water bath for 3 minutes. The mixture was incubated in a room temperature water bath immediately after heat shock for 17 min. Results were recorded 22 hours after transformation. The ratios of transformants obtained with and without heat shock were very similar (~25%), but we observed an adverse effect of heat shock on the viability of the protoplasts (data not shown).
<img src="/files/ftp_upload/2560/2560fig1.jpg" alt="Figure 1" /> 
Figure 1. View of protoplasts in hemocytometer. The section needed for protoplast counting is indicated by a red square. Note the 16 squares required for counting protoplasts (see 1.11); the image shows a count of 24 protoplasts (240,000 cells/ mL).
<img src="/files/ftp_upload/2560/2560fig2.jpg" alt="Figure 2" /> 
Figure 2. Pictures of 18 day old transient transformants. Protoplasts were transformed with the indicated amount of supercoiled plasmid. A: 15&mu;g; B: 30&mu;g; C: 60&mu;g; D: 120&mu;g.
<table border="1">
<tbody>
 <tr>
 <td>Amount of DNA (&mu;g)</td>
 <td>Efficiency (tranformants/&mu;g DNA)</td>
 </tr>
 <tr>
 <td>15, supercoiled plasmid</td>
 <td>120&plusmn;24</td>
 </tr>
 <tr>
 <td>30, supercoiled plasmid</td>
 <td>145&plusmn;54</td>
 </tr>
 <tr>
 <td>60, supercoiled plasmid</td>
 <td>121&plusmn;60</td>
 </tr>
 <tr>
 <td>120, supercoiled plasmid</td>
 <td>71&plusmn;38</td>
 </tr>
 <tr>
 <td>60, linearized plasmid</td>
 <td>4&plusmn;1</td>
 </tr>
 </tbody>
</table>
Table 1. Transformation efficiency at various DNA amounts.

<ol>
	<li>Abel, S., Theologis, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transient+transformation+of+Arabidopsis+leaf+protoplasts:+a+versatile+experimental+system+to+study+gene+expression.">Transient transformation of Arabidopsis leaf protoplasts: a versatile experimental system to study gene expression.</a> Plant J. 5, 421-427 (1994).</li><li>Wood, A. J., Oliver, M. J., Cove, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bryophytes+as+model+systems.">Bryophytes as model systems.</a> Bryologist. 103, 128-133 (2000).</li><li>Schaefer, D. G., Zr&#255;d, J. -. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+gene+targeting+in+the+moss+Physcomitrella+patens.">Efficient gene targeting in the moss Physcomitrella patens.</a> Plant J. 11, 1195-1206 (1997).</li><li>Schaefer, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+targeting+in+Physcomitrella+patens.">Gene targeting in Physcomitrella patens.</a> Curr. Opin. Plant Biol. 4, 143-150 (2001).</li><li>Kamisugi, Y., Cuming, A. C., Cove, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parameters+determining+the+efficiency+of+gene+targeting+in+the+moss+Physcomitrella+patens.">Parameters determining the efficiency of gene targeting in the moss Physcomitrella patens.</a> Nucleic Acids Res. 33, e173-e173 (2005).</li><li>Cove, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+moss+Physcomitrella+patens.">The moss Physcomitrella patens.</a> Annu. Rev. 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W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+bryophyte+Physcomitrella+patens+replicates+extrachromosomal+transgenic+elements.">The bryophyte Physcomitrella patens replicates extrachromosomal transgenic elements.</a> New Phytol. 146, 391-402 (2000).</li><li>Hohe, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+and+highly+standardized+transformation+procedure+allows+efficient+production+of+single+and+multiple+targeted+gene-knockouts+in+a+moss,+Physcomitrella+patens.">An improved and highly standardized transformation procedure allows efficient production of single and multiple targeted gene-knockouts in a moss, Physcomitrella patens.</a> Curr. 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No conflicts of interest declared.

The method presented here enables a straightforward and consistent DNA transformation into Physcomitrella patens protoplasts. This method was originally developed for Arabidopsis1, but here we demonstrated that it performs well with protoplasts of Physcomitrella patens, a simpler and different plant. Therefore, this method can be applied to other plant species with minor modifications. Possible modifications for optimization include protoplast concentration in MMg, incubation time in MMg and PEG/Ca solution. We choose to use 60 &mu;g DNA in our routine experiments because the number of transformants increases linearly with the DNA concentration until this point (Table 1). We could get approximately 7000 transient transformants or 200 stable transformants on a single 60 &mu;g DNA transformation, which allows for further screening and analysis of a large population of plants.
The transformed protoplasts can be either spread with liquid plating medium or PRM-T. Although the regeneration efficiency is lower when liquid plating medium is used, we choose this method when the protoplasts were transformed with supercoiled plasmids. As showed in Table 1, transformations done with supercoiled plasmid DNA generate many more transformants and thus, we can still obtain large numbers of plants with liquid plating medium. Furthermore, spreading protoplasts with liquid plating medium allows faster regeneration, which is important for experiments involving transient phenotypes, such as RNAi knock down experiments9,15. In addition the absence of top agar allows for easy plant isolation for immunostaining and RT-PCR9,15.

<table border="1">
<tbody>
 <tr>
 <td>Name of the reagent</td>
 <td>Ingredient</td>
 </tr>
 <tr>
 <td>PPNH4</td>
 <td>1.84 mM KH2PO4 
 3.4 mM Ca(NO3)2 
 1 mM MgSO4 
 2.72 mM Diammonium tartrate 
 54 &mu;M FeSO4.7H2O 
 9.93 &mu;M H3BO3 
 1.97 &mu;M MnCl2.4H2O 
 0.23 &mu;M CoCl2.6H2O 
 0.19 &mu;M ZnSO4. 7H2O 
 0.22 &mu;M CuSO4. 5H2O 
 0.10 &mu;M Na2MoO4.2H2O 
 0.168 &mu;M KI 
 Add 0.7% agar for solid medium.</td>
 </tr>
 <tr>
 <td>PRM-B</td>
 <td>PPNH4 with 6% mannitol and 0.8% agar. Add 10 mL 1M CaCl2 to 1 L before pouring plates. </td>
 </tr>
 <tr>
 <td>PRM-T</td>
 <td>PPNH4 with 6% mannitol and 0.6% agar. Add 0.5 mL 1M CaCl2 to 50 mL before use.</td>
 </tr>
 <tr>
 <td>Liquid Plating Medium</td>
 <td>PPNH4 with 8.5% mannitol without agar. Add 0.5 mL 1M CaCl2 to 50 mL before use.</td>
 </tr>
 <tr>
 <td>2% Driselase</td>
 <td>Add 4 g of Driselase (Sigma D9515-25G) to 200 mL of 8% mannitol. Stir gently for 30 min. at room temperature, incubate 30 min. at 4&deg;C, and stir gently for 5 min. at room temperature. Spin 2,500 g for 10 min, discard pellet. Filter with 0.22 &mu;m, and store frozen as 10 mL aliquots. Thaw in a room temperature water bath before use.</td>
 </tr>
 <tr>
 <td>MMg</td>
 <td>0.4 M mannitol 
 15 mM MgCl2 
 4 mM MES (pH 5.7)</td>
 </tr>
 <tr>
 <td>PEG/Ca</td>
 <td>4 g PEG4000 
 3 mL H2O 
 2.5 mL 0.8 M mannitol 
 1 mL 1M CaCl2</td>
 </tr>
 <tr>
 <td>W5</td>
 <td>154 mM NaCl 
 125 mM CaCl2 
 5 mM KCl 
 2 mM MES (pH 5.7) </td>
 </tr>
</tbody>
</table>

efficient polyethylene glycol (peg) mediated transformation of the moss physcomitrella patens

A simple and efficient method to transform Physcomitrella pantens protoplasts is described. This method is adapted from protocols for Physocmitrella protonemal protoplast and Arabidopsis mesophyll protoplast transformation1. Due to its capacity to undergo efficient mitotic homologous recombination, Physcomitrella patens has emerged as an important model system in recent years2. This capacity allows high frequencies of gene targeting3-9, which is not seen in other model plants such as Arabidopsis. To take full advantage of this system, we need an effective and easy method to deliver DNA into moss cells. The most common ways to transform this moss are particle bombardment10 and PEG-mediated DNA uptake11. Although particle bombardment can produce a high transformation efficiency12, gene guns are not readily available to many laboratories and the protocol is difficult to standardize. On the other hand, PEG mediated transformation does not require specialized equipments, and can be performed in any laboratory with a sterile hood. Here, we show a simple and highly efficient method for transformation of moss protoplasts. This method can generate more than 120 transient transformants per microgram of DNA, which is an improvement from the most efficient protocol previously reported13. Because of its simplicity, efficiency, and reproducibility, this method can be applied to projects requiring large number of transformants as well as for routine transformation.

Watch this Scientific Journal Video about Efficient Polyethylene Glycol PEG Mediated Transformation of the Moss Physcomitrella patens at JoVE.com

Efficient Polyethylene Glycol PEG Mediated Transformation of the Moss Physcomitrella patens

A simple and efficient method to transform Physcomitrella pantens protoplasts is described. This method is adapted from protocols for Physocmitrella protonemal protoplast and Arabidopsis mesophyll protoplast transformation1.

Efficient Polyethylene Glycol (PEG) Mediated Transformation of the Moss Physcomitrella patens

A simple and efficient method to transform Physcomitrella pantens protoplasts is described. This method is adapted from protocols for Physocmitrella ...

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40.5K 조회수.  Worcester Polytechnic Institute- WPI. 변환하는 간단하고 효율적인 방법 Physcomitrella pantens protoplasts이 설명되어 있습니다. 이 방법은을 위해 프로토콜에서 적응됩니다 Physocmitrella protonemal 원형질과 Arabidopsis mesophyll의 원형질 변환 1.

비디오: Efficient Polyethylene Glycol PEG Mediated Transformation of the Moss Physcomitrella patens

Environmentally Induced Heritable Changes in Flax

Some flax varieties respond to nutrient stress by modifying their genome and these modifications can be inherited through many generations. Also associated with these genomic changes are heritable phenotypic variations 1,2. The flax variety Stormont Cirrus (Pl) when grown under three different nutrient conditions can either remain inducible (under the control conditions), or become stably modified to either the large or small genotroph by growth under high or low nutrient conditions respectively. The lines resulting from the initial growth under each of these conditions appear to grow better when grown under the same conditions in subsequent generations, notably the Pl line grows best under the control treatment indicating that the plants growing under both the high and low nutrients are under stress. One of the genomic changes that are associated with the induction of heritable changes is the appearance of an insertion element (LIS-1) 3, 4 while the plants are growing under the nutrient stress. With respect to this insertion event, the flax variety Stormont Cirrus (Pl) when grown under three different nutrient conditions can either remain unchanged (under the control conditions), have the insertion appear in all the plants (under low nutrients) and have this transmitted to the next generation, or have the insertion (or parts of it) appear but not be transmitted through generations (under high nutrients) 4. The frequency of the appearance of this insertion indicates that it is under positive selection, which is also consistent with the growth response in subsequent generations. Leaves or meristems harvested at various stages of growth are used for DNA and RNA isolation. The RNA is used to identify variation in expression associated with the various growth environments and/or t he presence/absence of LIS-1. The isolated DNA is used to identify those plants in which the insertion has occurred.

Growing some flax varieties under nutrient stress results in genomic variation within a subset of the genome and phenotypic variation. A complex insertion at a specific site is associated with growth under various nutrient regimes and with changes in gene expression around this site.

Some flax varieties respond to nutrient stress by modifying their genome and these modifications can be inherited through many generations. Also ...

Cryopreservation of Mouse Embryos by Ethylene Glycol-Based Vitrification

Cryopreservation of mouse embryos is a technological basis that supports biomedical sciences, because many strains of mice have been produced by genetic modifications and the number is consistently increasing year by year. Its technical development started with slow freezing methods in the 1970s1, then followed by vitrification methods developed in the late 1980s2. Generally, the latter technique is advantageous in its quickness, simplicity, and high survivability of recovered embryos. However, the cryoprotectants contained are highly toxic and may affect subsequent embryo development. Therefore, the technique was not applicable to certain strains of mice, even when the solutions are cooled to 4&deg;C to mitigate the toxic effect during embryo handling. At the RIKEN BioResource Center, more than 5000 mouse strains with different genetic backgrounds and phenotypes are maintained3, and therefore we have optimized a vitrification technique with which we can cryopreserve embryos from many different strains of mice, with the benefits of high embryo survival after vitrifying and thawing (or liquefying, more precisely) at the ambient temperature4.
Here, we present a vitrification method for mouse embryos that has been successfully used at our center. The cryopreservation solution contains ethylene glycol instead of DMSO to minimize the toxicity to embryos5. It also contains Ficoll and sucrose for prevention of devitrification and osmotic adjustment, respectively. Embryos can be handled at room temperature and transferred into liquid nitrogen within 5 min. Because the original method was optimized for plastic straws as containers, we have slightly modified the protocol for cryotubes, which are more easily accessible in laboratories and more resistant to physical damages. We also describe the procedure of thawing vitrified embryos in detail because it is a critical step for efficient recovery of live mice. These methodologies would be helpful to researchers and technicians who need preservation of mouse strains for later use in a safe and cost-effective manner.

An ethylene glycol-based vitrification method for mouse embryos is described. It is advantageous to other methods in its simplicity and low embryonic toxicity, and therefore can be broadly applicable to many strains of mice, including inbred and gene-modified mice.

Cryopreservation of mouse embryos is a technological basis that supports biomedical sciences, because many strains of mice have been produced by genetic ...

Genomic Transformation of the Picoeukaryote Ostreococcus tauri

Common problems hindering rapid progress in Plant Sciences include cellular, tissue and whole organism complexity, and notably the high level of genomic redundancy affecting simple genetics in higher plants. The novel model organism Ostreococcus tauri is the smallest free-living eukaryote known to date, and possesses a greatly reduced genome size and cellular complexity1,2, manifested by the presence of just one of most organelles (mitochondrion, chloroplast, golgi stack) per cell, and a genome containing only ~8000 genes. Furthermore, the combination of unicellularity and easy culture provides a platform amenable to chemical biology approaches. Recently, Ostreococcus has been successfully employed to study basic mechanisms underlying circadian timekeeping3-6. Results from this model organism have impacted not only plant science, but also mammalian biology7. This example highlights how rapid experimentation in a simple eukaryote from the green lineage can accelerate research in more complex organisms by generating testable hypotheses using methods technically feasible only in this background of reduced complexity. Knowledge of a genome and the possibility to modify genes are essential tools in any model species. Genomic1, Transcriptomic8, and Proteomic9 information for this species is freely available, whereas the previously reported methods6,10 to genetically transform Ostreococcus are known to few laboratories worldwide.
In this article, the experimental methods to genetically transform this novel model organism with an overexpression construct by means of electroporation are outlined in detail, as well as the method of inclusion of transformed cells in low percentage agarose to allow selection of transformed lines originating from a single transformed cell. Following the successful application of Ostreococcus to circadian research, growing interest in Ostreococcus can be expected from diverse research areas within and outside plant sciences, including biotechnological areas. Researchers from a broad range of biological and medical sciences that work on conserved biochemical pathways may consider pursuing research in Ostreococcus, free from the genomic and organismal complexity of larger model species.

Genomic Transformation of the Picoeukaryote Ostreococcus tauri

This article describes genetic transformation of the unicellular marine alga Ostreococcus tauri by electroporation. This eukaryotic organism is an effective model platform for higher plants, possesing greatly reduced genomic and cellular complexity and being readily amenable to both cell culture and chemical biology.

Common problems hindering rapid progress in Plant Sciences include cellular, tissue and whole organism complexity, and notably the high level of genomic ...

Efficient Agroinfiltration of Plants for High-level Transient Expression of Recombinant Proteins

Mammalian cell culture is the major platform for commercial production of human vaccines and therapeutic proteins. However, it cannot meet the increasing worldwide demand for pharmaceuticals due to its limited scalability and high cost. Plants have shown to be one of the most promising alternative pharmaceutical production platforms that are robust, scalable, low-cost and safe. The recent development of virus-based vectors has allowed rapid and high-level transient expression of recombinant proteins in plants. To further optimize the utility of the transient expression system, we demonstrate a simple, efficient and scalable methodology to introduce target-gene containing Agrobacterium into plant tissue in this study. Our results indicate that agroinfiltration with both syringe and vacuum methods have resulted in the efficient introduction of Agrobacterium into leaves and robust production of two fluorescent proteins; GFP and DsRed. Furthermore, we demonstrate the unique advantages offered by both methods. Syringe infiltration is simple and does not need expensive equipment. It also allows the flexibility to either infiltrate the entire leave with one target gene, or to introduce genes of multiple targets on one leaf. Thus, it can be used for laboratory scale expression of recombinant proteins as well as for comparing different proteins or vectors for yield or expression kinetics. The simplicity of syringe infiltration also suggests its utility in high school and college education for the subject of biotechnology. In contrast, vacuum infiltration is more robust and can be scaled-up for commercial manufacture of pharmaceutical proteins. It also offers the advantage of being able to agroinfiltrate plant species that are not amenable for syringe infiltration such as lettuce and Arabidopsis. Overall, the combination of syringe and vacuum agroinfiltration provides researchers and educators a simple, efficient, and robust methodology for transient protein expression. It will greatly facilitate the development of pharmaceutical proteins and promote science education.

Plants offer a novel system for the production of pharmaceutical proteins on a commercial scale that is more scalable, cost-efficient and safe than current expression paradigms. In this study, we report a simple and convenient, yet scalable approach to introduce target-gene containing Agrobacterium tumefaciens into plants for protein transient expression.

Mammalian cell culture is the major platform for commercial production of human vaccines and therapeutic proteins. However, it cannot meet the increasing ...

Agrobacterium-Mediated Immature Embryo Transformation of Recalcitrant Maize Inbred Lines Using Morphogenic Genes

Demonstrated here is a detailed protocol for Agrobacterium-mediated genetic transformation of maize inbred lines using morphogenic genes Baby boom (Bbm) and Wuschel2 (Wus2). Bbm is regulated by the maize phospholipid transferase gene (Pltp) promoter, and Wus2 is under the control of a maize auxin-inducible (Axig1) promoter. An Agrobacterium strain carrying these morphogenic genes on transfer DNA (T-DNA) and extra copies of Agrobacterium virulence (vir) genes are used to infect maize immature embryo explants. Somatic embryos form on the scutella of infected embryos and can be selected by herbicide resistance and germinated into plants. A heat-activated cre/loxP recombination system built into the DNA construct allows for removal of morphogenic genes from the maize genome during an early stage of the transformation process. Transformation frequencies of approximately 14%, 4%, and 4% (numbers of independent transgenic events per 100 infected embryos) can be achieved for W22, B73, and Mo17, respectively, using this protocol.

Agrobacterium-Mediated Immature Embryo Transformation of Recalcitrant Maize Inbred Lines Using Morphogenic Genes

Plant morphogenic genes can be used to improve genetic transformation of recalcitrant genotypes. Described here is an Agrobacterium-mediated genetic transformation (QuickCorn) protocol for three important public maize inbred lines.

Demonstrated here is a detailed protocol for Agrobacterium-mediated genetic transformation of maize inbred lines using morphogenic genes Baby boom (Bbm) ...

Preparing and Injecting Embryos of Culex Mosquitoes to Generate Null Mutations using CRISPR/Cas9

Culex mosquitoes are the major vectors of several diseases that negatively impact human and animal health including West Nile virus and diseases caused by filarial nematodes such as canine heartworm and elephantasis. Recently, CRISPR/Cas9 genome editing has been used to induce site-directed mutations by injecting a Cas9 protein that has been complexed with a guide RNA (gRNA) into freshly laid embryos of several insect species, including mosquitoes that belong to the genera Anopheles and Aedes. Manipulating and injecting Culex mosquitoes is slightly more difficult as these mosquitoes lay their eggs upright in rafts rather than individually like other species of mosquitoes. Here we describe how to design gRNAs, complex them with Cas9 protein, induce female mosquitoes of Culex pipiens to lay eggs, and how to prepare and inject newly laid embryos for microinjection with Cas9/gRNA. We also describe how to rear and screen injected mosquitoes for the desired mutation. The representative results demonstrate that this technique can be used to induce site-directed mutations in the genome of Culex mosquitoes and, with slight modifications, can be used to generate null-mutants in other mosquito species as well.&#160;

Preparing and Injecting Embryos of Culex Mosquitoes to Generate Null Mutations using CRISPR/Cas9

CRISPR/Cas9 is increasingly used to characterize gene function in non-model organisms. This protocol describes how to generate knock-out lines of Culex pipiens, from preparing injection mixes, to obtaining and injecting mosquito embryos, as well as how to rear, cross, and screen injected mosquitoes and their progeny for desired mutations.

Culex mosquitoes are the major vectors of several diseases that negatively impact human and animal health including West Nile virus and diseases caused by ...

Agrobacterium-Mediated Genetic Transformation, Transgenic Production, and Its Application for the Study of Male Reproductive Development in Rice

Male sterility is an important agronomic trait for hybrid seed production that is usually characterized by functional defects in male reproductive organs/gametes. Recent advances in CRISPR-Cas9 genome editing technology allow for high editing efficacy and timesaving knockout mutations of endogenous candidate genes at specific sites. Additionally, Agrobacterium-mediated genetic transformation of rice is also a key method for gene modification, which has been widely adopted by many public and private laboratories. In this study, we applied CRISPR-Cas9 genome editing tools and successfully generated three male sterile mutant lines by targeted genome editing of OsABCG15 in a japonica cultivar. We used a modified Agrobacterium-mediated rice transformation method that could provide excellent means of genetic emasculation for hybrid seed production in rice. Transgenic plants can be obtained within 2&#8211;3 months and homozygous transformants were screened by genotyping using PCR amplification and Sanger sequencing. Basic phenotypic characterization of the male sterile homozygous line was performed by microscopic observation of the rice male reproductive organs, pollen viability analysis by iodine potassium iodide (I2-KI) staining semi-thin cross-sectioning of developing anthers.

Agrobacterium-Mediated Genetic Transformation, Transgenic Production, and Its Application for the Study of Male Reproductive Development in Rice

This work describes the use of CRISPR-Cas9 genome editing technology to knockout endogenous gene OsABCG15 followed by a modified Agrobacterium-mediated transformation protocol to produce a stable male-sterile line in rice.

Male sterility is an important agronomic trait for hybrid seed production that is usually characterized by functional defects in male reproductive ...

Hyperactive piggyBac Transposase-mediated Germline Transformation in the Fall Armyworm, Spodoptera frugiperda

Stable insertion of genetic cargo into insect genomes using transposable elements is a powerful tool for functional genomic studies and developing genetic pest management strategies. The most used transposable element in insect transformation is piggyBac, and piggyBac-based germline transformation has been successfully conducted in model insects. However, it is still challenging to employ this technology in non-model insects that include agricultural pests. This paper reports on germline transformation of a global agricultural pest, the fall armyworm (FAW), Spodoptera frugiperda, using the hyperactive piggyBac transposase (hyPBase).
In this work, the hyPBase mRNA was produced and used in place of helper plasmid in embryo microinjections. This change led to the successful generation of transgenic FAW. Furthermore, the methods of screening transgenic animals, PCR-based rapid detection of transgene insertion, and thermal asymmetric interlaced PCR (TAIL-PCR)-based determination of the integration site, are also described. Thus, this paper presents a protocol to produce transgenic FAW, which will facilitate piggyBac-based transgenesis in FAW and other lepidopteran insects.

Hyperactive piggyBac Transposase-mediated Germline Transformation in the Fall Armyworm, Spodoptera frugiperda

Successful germline transformation in the fall armyworm, Spodoptera frugiperda, was achieved using mRNA of hyperactive piggyBac transposase.

Stable insertion of genetic cargo into insect genomes using transposable elements is a powerful tool for functional genomic studies and developing genetic ...

Agrobacterium tumefaciens-Mediated Genetic Transformation of Narrowleaf Plantain

Species in the genus Plantago have several unique traits that have led to them being adapted as model plants in various fields of study. However, the lack of a genetic manipulation system prevents in-depth investigation of gene function, limiting the versatility of this genus as a model. Here, a transformation protocol is presented for Plantago lanceolata, the most commonly studied Plantago species. Using Agrobacterium tumefaciens-mediated transformation, 3 week-old roots of aseptically grown P. lanceolata plants were infected with bacteria, incubated for 2-3 days, and then transferred to a shoot induction medium with appropriate antibiotic selection. Shoots typically emerged from the medium after 1 month, and roots developed 1-4 weeks after the shoots were transferred to the root induction medium. The plants were then acclimated to a soil environment and tested for the presence of a transgene using the &#946;-glucuronidase (GUS) reporter assay. The transformation efficiency of the current method is ~20%, with two transgenic plants emerging per 10 root tissues transformed. Establishing a transformation protocol for narrowleaf plantain will facilitate the adoption of this plant as a new model species in various areas.

Agrobacterium tumefaciens-Mediated Genetic Transformation of Narrowleaf Plantain

Because of its versatile application as a model species in various fields of study, there is a need for a genetic transformation toolkit in narrowleaf plantain (Plantago lanceolata). Here, using Agrobacterium tumefaciens-mediated transformation, a protocol is presented that results in stable transgenic lines with a transformation efficiency of 20%.

Species in the genus Plantago have several unique traits that have led to them being adapted as model plants in various fields of study. However, the lack ...

One-Step Hairy Root Transformation Method for Advancing Root-Related Biology

An Efficient and Reproducible Method for Producing Composite Plants by Agrobacterium rhizogenes-Based Hairy Root Transformation

Producing composite plants with transgenic roots and nontransgenic stems and buds using Agrobacterium rhizogenes-mediated hairy root transformation is a powerful tool to study root-related biology. Hairy root transformation is established in a wide range of dicotyledons and in several monocotyledon species and is almost independent of the genotype. The traditional method of hypocotyl injection with A. rhizogenes to obtain composite plants is inefficient, time-consuming, laborious, and frequently causes the death of tender and tiny hypocotyl plants. A highly efficient, one-step hairy root transformation mediated by A. rhizogenes was established previously, which eliminates the need for transplanting after producing hairy roots. In this study, a partial hypocotyl and primary root were removed, the hypocotyl incision site was coated with A. rhizogenes, and&#160;then hypocotyls were planted in sterile vermiculite. After 12 days of cultivation, the hypocotyl incision expanded and new hairy roots were induced. This article provides the detailed protocol of a one-step transformation method mediated by A. rhizogenes, with its effectiveness demonstrated by producing composite plants of wild soybean, Solanum americanum, and pumpkin.

Author Spotlight: Streamlining Composite Plant Production via Agrobacterium rhizogenes-Mediated Hairy Root Transformation 

Here, we provide the detailed protocol of a one-step transformation method mediated by Agrobacterium tumefaciens to produce composite plants.

Producing composite plants with transgenic roots and nontransgenic stems and buds using Agrobacterium rhizogenes-mediated hairy root transformation is a ...