Name: transforming, genome editing and phenotyping the nitrogen-fixing tropical cannabaceae tree parasponia andersonii
Uploaded: 2019-08-18T13:00:00
Duration: 12 min 22 s
Description: Watch this Scientific Journal Video about Transforming, Genome Editing and Phenotyping the Nitrogen-fixing Tropical Cannabaceae Tree Parasponia andersonii at JoVE.com

The authors like to acknowledge Mark Youles, Sophien Kamoun and Sylvestre Marillonnet for making Golden Gate cloning parts available through the Addgene database. Additionally, we would like to thank E. James, P. Hadobas, and T. J. Higgens for P. andersonii seeds. This work was supported by The Netherlands Organization for Scientific Research (NWO-VICI grant 865.13.001; NWO-Open Competition grant 819.01.007) and The Ministry of Research, Technology and Higher Education of the Republic of Indonesia (RISET-PRO grant 8245-ID).

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The authors have nothing to disclose.

Legumes and the distantly-related Cannabaceae genus Parasponia represent the only two clades of plant species able to establish an endosymbiotic relationship with nitrogen-fixing rhizobia and form root nodules. Comparative studies between species of both clades are highly relevant to provide insights into the core genetic networks allowing this symbiosis. Currently, genetic studies are mainly done in legumes; especially the two model species M. truncatula and L. japonicus. To provide an additional experimental platform and facilitate comparative studies with a nodulating non-legume, we describe here a detailed protocol for stable transformation and reverse genetic analyses in P. andersonii. The presented protocol uses in vitro propagation of T0 transgenic P. andersonii lines, allowing phenotypic analysis to be initiated within 4 months after A. tumefaciens co-cultivation. This is substantially faster than current protocols that have been established for stable transformation of legumes33. This makes P. andersonii an attractive research model.
The protocol described here contains several critical steps. The first of which concerns seed germination. To prepare P. andersonii seeds for germination, seeds need to be isolated from the berries. This is done by rubbing the berries on a piece of tissue paper or against the inside of a tea sieve. This procedure needs to be performed gently in order to prevent damage to the seed coat. If the seed coat gets damaged, bleach could enter the seed during sterilization, which reduces seed viability. To break seed dormancy, seeds are subjected to a 10-day temperature cycle. However, despite this treatment, germination is not entirely synchronized. Generally, the first seeds show radicle emergence after 7 days, but others might take several days longer to germinate.
Critical points in the transformation procedure concern the choice of the starting material and the duration of the co-cultivation step. To reach efficient transformation, it is best to use healthy and young stems or petioles of non-sterile greenhouse-grown plants as the starting material. In order to induce the growth of young branches, it is advisable to trim Parasponia trees every 2-3 months and refresh trees once a year. Additionally, the co-cultivation step needs to be performed for 2 days only. Prolonged co-cultivation promotes over-colonization of tissue explants by A. tumefaciens and generally reduces transformation efficiency. To prevent over-colonization by A. tumefaciens it is also important to regularly refresh the plates on which the explants are cultivated. In case over-colonization does occur, tissue explants could be washed (see Section 3.8) to remove A. tumefaciens cells. We advise adding bleach to the SH-10 solution used for washing (final concentration: ~2% hypochlorite). It is important to note that this additional washing step might not work on heavily-infected explants (Figure 2B). In case a transformation with a CRISPR/Cas9 construct yields only a limited number of putatively-transformed shoots or if mutagenesis of a particular gene is expected to cause problems in regeneration, it is advisable to include an empty vector control construct as the positive control. Lastly, it is important to ensure that all transgenic lines that are selected are resulting from independent T-DNA integration events. Therefore, we instruct to take only a single putatively-transgenic shoot from each side of an explant. However, we realize that this reduces the potential number of independent lines. If many lines are required, researchers could decide to separate putatively-transformed calli from the original explants when these calli are &#8805;2 mm in size and culture these calli independently. In this way, multiple lines could be isolated from each explant, which raises the number of potential transgenic lines.
In the current protocol, transgenic lines of P. andersonii are propagated vegetatively through in vitro propagation. The advantage of this is that many transgenic plantlets can be generated in a relatively short time period. However, this method also has several limitations. Firstly, the maintenance of T0 transgenic lines through in vitro propagation is labor intensive and could result in unwanted genetic or epigenetic alterations34,35. Secondly, T0 lines still contain a copy of the T-DNA, including the antibiotic resistance cassette. This limits the number of possible re-transformations, as different selection markers are required for each re-transformation. Currently, we have only tested transformation using kanamycin or hygromycin selection (data not shown). Furthermore, the presence of the Cas9-encoding sequence and sgRNAs in the T0 transgenic lines complicates complementation studies. Complementation assays are possible but require the sgRNA target site(s) to be mutated as such that gene-editing of the complementation construct is prevented. Thirdly, a disadvantage of working with T0 lines is that CRISPR/Cas9 mutants might be chimeric. To prevent phenotypic analysis of chimeric mutant lines, we recommend repeating the genotyping analysis after in vitro propagation on at least 3 different shoots. Although, the number of chimeric mutants obtained using the protocol described here is limited, they are occasionally observed10. To overcome the limitations of working with T0 lines, P. andersonii mutant lines could be propagated generatively. P. andersonii trees are dioecious and wind-pollinated2. This means that each transgenic line needs to be manipulated as such that male and female flowers are produced on a single individual, and subsequently grown as such that cross pollination does not occur. As P. andersonii is a fast-growing tree it requires a substantial amount of space in a tropical greenhouse (28 &#176;C, ~85% relative humidity). Therefore, although technically possible, generative propagation of P. andersonii transgenic lines is logistically challenging.
In the protocol section, we described 3 methods for nodulation of P. andersonii. The advantage of the plate and pouch systems is that the roots are easily accessible, which may allow spot-inoculation of bacteria and following nodule formation over time. However, the plate system is quite labor intensive, which makes it less suited for large-scale nodulation experiments. A disadvantage of the pouch system is that it is difficult to prevent fungal contamination. Pouches are not sterile, and therefore fungal growth is often observed on the top half of the pouch. However, this does not affect P. andersonii growth, and therefore does not interfere with nodulation assays. Additionally, the pouch system is only suitable for seedlings. Despite several attempts, we have been unable to grow plantlets obtained through in vitro propagation in pouches.
The P. andersonii reverse genetics pipeline described here offers a substantial improvement compared to the existing A. rhizogenes-based root transformation method11. Using the described procedures, stable transgenic lines can be generated efficiently and can be maintained via in vitro propagation. In contrast, A. rhizogenes transformation is transient and only results in the formation of transgenic roots. Because each transgenic root results from an independent transformation, A. rhizogenes&#173; transformation-based assays suffer from substantial phenotypic variation. This variation is much less in case of stable lines, although in vitro propagation also creates some level of variation. Because of this reduced variation and the fact that multiple plantlets could be phenotyped for each stable line, stable lines are more suited for quantitative assays compared to A. rhizogenes-transformed roots. Additionally, the stable transformation does not depend on the introduction of the A. rhizogenes root inducing locus (rol) that affects the endogenous hormone balance15. Therefore, stable lines are better suited for reverse genetic analysis of genes involved in hormone homeostasis compared to A. rhizogenes-transformed roots. A more general advantage of P. andersonii as research model is that it did not experience a recent whole genome duplication (WGD). The legume Papilionoideae subfamily, which includes the model legumes M. truncatula and L. japonicus, as well as the Salicaceae (order Malpighiales) that includes the model tree Populus trichocarpa experienced WGDs ~65 million years ago36,37. Many paralogous gene copies resulting from these WGDs are retained in the genomes of M. truncatula, L. japonicus and P. trichocarpa37,38,39, which creates redundancy that might complicate reverse genetic analyses. As P. andersonii did not experience a recent WGD, reverse genetic analyses on P. andersonii might be less affected by redundant functioning of paralogous gene copies.
Taken together, we provide a detailed protocol for reverse genetic analysis in P. andersonii. Using this protocol, single mutant lines can be efficiently generated in a timeframe of 2-3 months10. This protocol can be extended to create higher order mutants through multiplexing of sgRNAs targeting different genes simultaneously, as shown for other plant species40,41,42. Additionally, the stable transformation procedure described here is not limited to CRISPR/Cas9 gene-targeting but could also be used to introduce other types of constructs (e.g., for promoter-reporter assays, ectopic expression or trans-complementation). We established P. andersonii as a comparative research model to study mutualistic symbioses with nitrogen-fixing rhizobia or endomycorrhizal fungi. However, the protocols described here also provide tools to study other aspects of the biology of this tropical tree, such as wood formation, the development of bi-sexual flowers or the biosynthesis of Cannabaceae-specific secondary metabolites.

Parasponia andersonii is a tropical tree belonging to the Cannabis family (Cannabaceae) and is native to Papua New Guinea and several Pacific Islands1,2,3. Together with 4 additional Parasponia species, it represents the only non-legume lineage that can establish a nitrogen-fixing nodule symbiosis with rhizobia. This symbiosis is well studied in the legume (Fabaceae) models Medicago truncatula and Lotus japonicus, which has resulted in acquiring detailed knowledge of the molecular genetic nature of nodule formation and functioning4. Additionally, it was demonstrated that the root nodule symbiosis in legumes is founded on the much older, and widespread arbuscular mycorrhizal symbiosis5. Phylogenomic comparisons suggest that the nitrogen-fixing nodule symbioses of legumes, Parasponia, as well as, the so-called actinorhizal plant species that host diazotrophic Frankia bacteria, have a shared evolutionary origin6,7,8. To determine whether the genes identified to be involved in the legume nodule formation are the part of a conserved genetic basis, studies on non-legume species are essential. To this end, we propose to use P. andersonii as a comparative research model, alongside legumes, to identify the core genetic networks underlying root nodule formation and functioning.
P. andersonii is a pioneer that can be found on the slopes of volcanic hills. It can meet growth speeds of 45 cm per month and reach lengths of up to 10 meters9. P. andersonii trees are wind-pollinated, which is facilitated by the formation of separate male and female flowers3,10. We recently sequenced and annotated the diploid genome (2n = 20; 560 Mb/1C) of P. andersonii, and assembled draft genome sequences of 2 additional Parasponia species; P. rigida and P. rugosa6. This revealed ~35,000 P. andersonii gene models that can be clustered in &#62;20,000 orthogroups together with genes from M. truncatula, soybean (Glycine max), Arabidopsis thaliana, woodland strawberry (Fragaria vesca), Trema orientalis, black cotton poplar (Populus trichocarpa) and eucalypt (Eucalyptus grandis)6. Additionally, transcriptome comparisons between M. truncatula and P. andersonii identified a set of 290 putative orthologues that display a nodule-enhanced expression pattern in both species6. This provides an excellent resource for comparative studies.
To study the gene function in P. andersonii roots and nodules, a protocol for Agrobacterium rhizogenes-mediated root transformation has been established11. Using this protocol, compound plants bearing transgenic roots can be generated in a relatively short time frame. This method is, also, widely applied in the legume-symbiosis research12,13,14. However, the disadvantage of this method is that only roots are transformed and that each transgenic root represents an independent transformation event, resulting in substantial variation. Also, the transformation is transient and transgenic lines cannot be maintained. This makes A. rhizogenes-based root transformation less suited for CRISPR/Cas9-mediated genome editing. Additionally, A. rhizogenes transfers its root inducing locus (rol) genes to the plant genome, which once expressed interfere with hormone homeostasis15. This makes studying the role of plant hormones in A. rhizogenes-transformed roots challenging. To overcome these limitations, we recently developed a protocol for Agrobacterium tumefaciens-based transformation and CRISPR/Cas9-mediated mutagenesis of P. andersonii10.
Here, we provide a detailed description of the A. tumefaciens-based transformation procedure and reverse genetics pipeline developed for P. andersonii. Additionally, we provide protocols for the downstream handling of transgenic plantlets, including assays to study symbiotic interactions. Using the protocol described here, multiple transgenic lines can be generated in a 2-3 months period. In combination with CRISPR/Cas9-mediated mutagenesis, this allows efficient generation of knockout mutant lines. These mutant lines can be vegetatively propagated in vitro10,16,17, which allows sufficient material to be generated to start phenotypic characterization at 4 months after the transformation procedure has been initiated10. Together, this set of procedures should allow any lab to adopt P. andersonii as a research model for studies aimed at understanding rhizobial and mycorrhizal associations, as well as potentially other aspects of the biology of this tropical tree.

<table>
<tbody>
<tr>
<td>Sigma-Aldrich</td>
<td>N0640</td>
<td>NAA</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>M1503.0250</td>
<td>MES</td>
</tr>
<tr>
<td>Sigma-Aldrich</td>
<td>D134406</td>
<td>Acetosyringone</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>X1402.1000</td>
<td>X-Gal</td>
</tr>
<tr>
<td>Merck</td>
<td>101236</td>
<td>For nucleic acid electrophoresis gel</td>
</tr>
<tr>
<td>-</td>
<td>-</td>
<td>Pouches box material, hangers</td>
</tr>
<tr>
<td>Merck</td>
<td>101188</td>
<td>NH4NO3</td>
</tr>
<tr>
<td>Sigma-Aldrich</td>
<td>B3408-1G</td>
<td>BAP</td>
</tr>
<tr>
<td>Merck</td>
<td>100156</td>
<td>H3BO3</td>
</tr>
<tr>
<td>Thermo-Fisher</td>
<td>ER1011</td>
<td>Used as restriction enzyme in Golden Gate cloning assembly</td>
</tr>
<tr>
<td>Thermo-Fisher</td>
<td>15561020</td>
<td>Used in Golden Gate cloning assembly</td>
</tr>
<tr>
<td>Merck</td>
<td>137101</td>
<td>CaCl2&middot;2H2O</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>C0111.0025</td>
<td>C16H16N5O7S2Na</td>
</tr>
<tr>
<td>Thermo-Fisher</td>
<td>K1231</td>
<td>Used for cloning the blunt-ended PCR amplicons in genotyping procedure</td>
</tr>
<tr>
<td>Agronutrition</td>
<td>AP2011</td>
<td>Containing Rhizophagus irregularis DAOM 197198 (1,000 spores/mL), used for mychorrization assay</td>
</tr>
<tr>
<td>Merck</td>
<td>102790</td>
<td>CuSO4&middot;5H2O</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>D1004.1000</td>
<td>Used for plant tissue culture agar-based medium</td>
</tr>
<tr>
<td>Merck</td>
<td>105101</td>
<td>K2HPO4</td>
</tr>
<tr>
<td>VWR Chemicals</td>
<td>20302.293</td>
<td>Na2&middot;EDTA</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>M0803.1000</td>
<td>C6H14O6</td>
</tr>
<tr>
<td>Thermo-Fisher</td>
<td>ER0291</td>
<td>Used as restriction enzyme in Golden Gate cloning assembly</td>
</tr>
<tr>
<td>Merck</td>
<td>100983</td>
<td>C2H5OH</td>
</tr>
<tr>
<td>VWR Chemicals</td>
<td>BDH9232-500G</td>
<td>EDTA</td>
</tr>
<tr>
<td>Sigma-Aldrich</td>
<td>Z377600-1PAK</td>
<td>Cellophane membrane</td>
</tr>
<tr>
<td>Biomatters, Ltd.</td>
<td>R9 or higher</td>
<td>Bioinformatics software for in silico cloning and designing of sgRNAs</td>
</tr>
<tr>
<td>Mega International</td>
<td>-</td>
<td>Technical information at https://mega-international.com/tech-info/</td>
</tr>
<tr>
<td>Sigma-Aldrich</td>
<td>65882</td>
<td>Used for fixating nodule tissues</td>
</tr>
<tr>
<td>VWR Chemicals</td>
<td>24385.295</td>
<td>-</td>
</tr>
<tr>
<td>Vink</td>
<td>219341</td>
<td>Pouches box material, bottom part</td>
</tr>
<tr>
<td>Leica Biosystems</td>
<td>14702218311</td>
<td>Used as a template for plastic embedding</td>
</tr>
<tr>
<td>Merck</td>
<td>100317</td>
<td>HCl</td>
</tr>
<tr>
<td>Sigma-Aldrich</td>
<td>I5386-1G</td>
<td>IBA</td>
</tr>
<tr>
<td>Merck</td>
<td>103862</td>
<td>C6H5FeO7</td>
</tr>
<tr>
<td>Merck</td>
<td>103965</td>
<td>FeSO4O&middot;7H2O</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>I1401.0005</td>
<td>IPTG</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>K0126.0010</td>
<td>&nbsp;</td>
</tr>
<tr>
<td>Sigma-Aldrich</td>
<td>L2000</td>
<td>&nbsp;</td>
</tr>
<tr>
<td>Merck</td>
<td>105886</td>
<td>MgSO4O&middot;7H2O</td>
</tr>
<tr>
<td>Merck</td>
<td>105934</td>
<td>MnCl2&middot;4H2O</td>
</tr>
<tr>
<td>Merck</td>
<td>102786</td>
<td>MnSO4O</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>M1002.1000</td>
<td>Used for bacterial culture agar-based medium</td>
</tr>
<tr>
<td>Manutan</td>
<td>92007687</td>
<td>Pouches material</td>
</tr>
<tr>
<td>Paraxisdienst</td>
<td>130774</td>
<td>Elastic sealing foil</td>
</tr>
<tr>
<td>Pull Rhenen</td>
<td>Agra-Perlite No.3</td>
<td>Used as growing substrate in pots for nodulation assay</td>
</tr>
<tr>
<td>VWR Chemicals</td>
<td>391-0581</td>
<td>Used as container for cellophane membranes</td>
</tr>
<tr>
<td>Thermo-Fisher</td>
<td>F130WH</td>
<td>For genotyping transgenic lines</td>
</tr>
<tr>
<td>Addgene </td>
<td>50337</td>
<td>Level 0 terminator, 3'UTR, 35s (Cauliflower Mosaic Virus)</td>
</tr>
<tr>
<td>Addgene </td>
<td>48017</td>
<td>End-link 2 for assembling 2 level one part into a level 2 acceptor</td>
</tr>
<tr>
<td>Addgene </td>
<td>48018</td>
<td>End-link 3 for assembling 3 level one part into a level 2 acceptor</td>
</tr>
<tr>
<td>Addgene </td>
<td>48001</td>
<td>Level 1 acceptor. Position 5. Forward orientation</td>
</tr>
<tr>
<td>Addgene </td>
<td>48007</td>
<td>Level 1 Acceptor. Position 1. Reverse orientation</td>
</tr>
<tr>
<td>Addgene </td>
<td>50268</td>
<td>Level 0 promoter (0.4 kb), 35s (Cauliflower Mosaic Virus) + 5'UTR, &Omega; (Tobacco Mosaic Virus)</td>
</tr>
<tr>
<td>Addgene </td>
<td>46966</td>
<td>Used for designing CRISPR/Cas9 module</td>
</tr>
<tr>
<td>Addgene </td>
<td>46968</td>
<td>Used for designing CRISPR/Cas9 module</td>
</tr>
<tr>
<td>Addgene </td>
<td>50334</td>
<td>Level 0 Kanamycin/Neomycin/Paromomycin resistance cassette</td>
</tr>
<tr>
<td>Topzeven</td>
<td>-</td>
<td>Used as filters for washing spore suspension</td>
</tr>
<tr>
<td>Sigma-Aldrich</td>
<td>8.17003</td>
<td>PEG400</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>E1674.0001</td>
<td>Pots to grow Parasponia plantlets/seedlings</td>
</tr>
<tr>
<td>Merck</td>
<td>104871</td>
<td>KH2PO4</td>
</tr>
<tr>
<td>Merck</td>
<td>105033</td>
<td>KOH</td>
</tr>
<tr>
<td>Merck</td>
<td>105153</td>
<td>K2SO4O</td>
</tr>
<tr>
<td>Van Leusden b.v.</td>
<td>-</td>
<td>Used as growing substrate for mychorrhization assay</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>S0225.0050</td>
<td>SH-basal salt medium</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>S0411.0250</td>
<td>SH-vitamin mixture</td>
</tr>
<tr>
<td>Lehle Seeds</td>
<td>VIS-02</td>
<td>Used as non-ionic surfactant in the washing step of stable transformation</td>
</tr>
<tr>
<td>Merck</td>
<td>137017</td>
<td>NaCl</td>
</tr>
<tr>
<td>VWR Chemicals</td>
<td>89230-072</td>
<td>C6H11NaO7</td>
</tr>
<tr>
<td>Merck</td>
<td>106521</td>
<td>Na2MoO4&middot;2H2O</td>
</tr>
<tr>
<td>Merck</td>
<td>106574</td>
<td>Na2HPO4&middot;7H2O</td>
</tr>
<tr>
<td>Merck</td>
<td>567549</td>
<td>NaH2PO4&middot;H2O</td>
</tr>
<tr>
<td>Sigma-Aldrich</td>
<td>239313</td>
<td>Na2SO4O</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>S0809.5000</td>
<td>C12H22O11</td>
</tr>
<tr>
<td>Thermo-Fisher</td>
<td>B69</td>
<td>Used in Golden Gate cloning assembly</td>
</tr>
<tr>
<td>Thermo-Fisher</td>
<td>EL0013</td>
<td>Used in Golden Gate cloning assembly</td>
</tr>
<tr>
<td>Kulzer-Mitsui Chemicals Group</td>
<td>64708806</td>
<td>Methyl methacrylate-based resin powder</td>
</tr>
<tr>
<td>Kulzer-Mitsui Chemicals Group</td>
<td>64709003</td>
<td>HEMA (2-hydroxyethyl methacrylate)-based resin solution</td>
</tr>
<tr>
<td>Kulzer-Mitsui Chemicals Group</td>
<td>66022678</td>
<td>Methyl methacrylate-based resin solution</td>
</tr>
<tr>
<td>Merck</td>
<td>1159300025</td>
<td>&nbsp;</td>
</tr>
<tr>
<td>Acros</td>
<td>189350250</td>
<td>&nbsp;</td>
</tr>
<tr>
<td>VWR Chemicals</td>
<td>663684B</td>
<td>Polysorbate 20</td>
</tr>
<tr>
<td>Stout Perspex</td>
<td>-</td>
<td>pouches box material, lid</td>
</tr>
<tr>
<td>Duchefa Biochemie</td>
<td>Y1333.1000</td>
<td>&nbsp;</td>
</tr>
<tr>
<td>Merck</td>
<td>108816</td>
<td>ZnCl2</td>
</tr>
<tr>
<td>Alfa Aesar</td>
<td>33399</td>
<td>ZnSO4O&middot;7H2O</td>
</tr>
</tbody>
</table>

transforming, genome editing and phenotyping the nitrogen-fixing tropical cannabaceae tree parasponia andersonii

Parasponia andersonii is a fast-growing tropical tree that belongs to the Cannabis family (Cannabaceae). Together with 4 additional species, it forms the only known non-legume lineage able to establish a nitrogen-fixing nodule symbiosis with rhizobium. Comparative studies between legumes and P. andersonii could provide valuable insight into the genetic networks underlying root nodule formation. To facilitate comparative studies, we recently sequenced the P. andersonii genome and established Agrobacterium tumefaciens-mediated stable transformation and CRISPR/Cas9-based genome editing. Here, we provide a detailed description of the transformation and genome editing procedures developed for P. andersonii. In addition, we describe procedures for the seed germination and characterization of symbiotic phenotypes. Using this protocol, stable transgenic mutant lines can be generated in a period of 2-3 months. Vegetative in vitro propagation of T0 transgenic lines allows phenotyping experiments to be initiated at 4 months after A. tumefaciens co-cultivation. Therefore, this protocol takes only marginally longer than the transient Agrobacterium rhizogenes-based root transformation method available for P. andersonii, though offers several clear advantages. Together, the procedures described here permit P. andersonii to be used as a research model for studies aimed at understanding symbiotic associations as well as potentially other aspects of the biology of this tropical tree.

Watch this Scientific Journal Video about Transforming, Genome Editing and Phenotyping the Nitrogen-fixing Tropical Cannabaceae Tree Parasponia andersonii at JoVE.com

Transforming, Genome Editing and Phenotyping the Nitrogen-fixing Tropical Cannabaceae Tree Parasponia andersonii

Parasponia andersonii is a fast-growing tropical tree that belongs to the Cannabis family (Cannabaceae) and can form nitrogen-fixing root nodules in association with the rhizobium. Here, we describe a detailed protocol for reverse genetic analyses in P. andersonii based on Agrobacterium tumefaciens-mediated stable transformation and CRISPR/Cas9-based genome editing.

Transforming, Genome Editing and Phenotyping the Nitrogen-fixing Tropical Cannabaceae Tree Parasponia andersonii

Parasponia andersonii is a fast-growing tropical tree that belongs to the Cannabis family (Cannabaceae). Together with 4 additional species, it forms the ...

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