Name: expression of recombinant cellulase cel5a from trichoderma reesei in tobacco plants
Uploaded: 2014-06-13T15:00:00
Description: Watch this Scientific Journal Video about Expression of Recombinant Cellulase Cel5A from Trichoderma reesei in Tobacco Plants at JoVE.com

This work was supported by the BMBF Forschungsinitiative &#8220;BioEnergie 2021 &#8211; Forschung f&#252;r die Nutzung von Biomasse&#8221; and the Cluster of Excellence &#8220;Tailor-made Fuels from Biomass&#8221;, which is funded through the Excellence Initiative by the German federal and state governments to promote science and research at German universities.

1. Growth of Wild Type N. tabacum&#160;Plants
<ol>
	<li>To grow N. tabacum L. cv. Petit Havana SR1 plants on soil, place tobacco seeds on appropriate pots filled with normal potting soil for germination. After 2 weeks, transfer seedlings to individual pots. Incubate plants in a greenhouse with constant 22 &#176;C (dark period) or 25 &#176;C (light period) and 70% relative air humidity. Provide illumination in a 16/8&#160;hr light/dark cycle (e.g. Philips IP65 400 W lamps; 180 &#956;m...

<ol>
	<li>Garvey, M., Klose, H., Fischer, R., Lambertz, C., Commandeur, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellulases+for+biomass+degradation:+comparing+recombinant+cellulase+expression+platforms.">Cellulases for biomass degradation: comparing recombinant cellulase expression platforms.</a> Trends in Biotechnology. 31, 581-593 (2013).</li><li>Klose, H., G&#252;nl, M., Usadel, B., Fischer, R., Commandeur, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethanol+inducible+expression+of+a+mesophilic+cellulase+avoids+adverse+effects+on+plant+development.">Ethanol inducible expression of a mesophilic cellulase avoids adverse effects on plant development.</a> Biotechnology for Biofuels. 6, 53 (2013).</li><li>Klose, H., R&#246;der, J., Girfoglio, M., Fischer, R., Commandeur, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperthermophilic+endoglucanase+for+in+planta+lignocellulose+conversion.">Hyperthermophilic endoglucanase for in planta lignocellulose conversion.</a> Biotechnology for Biofuels. 5, 63 (2012).</li><li>Sharma, A. K., Sharma, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plants+as+bioreactors:+recent+developments+and+emerging+opportunities.">Plants as bioreactors: recent developments and emerging opportunities.</a> Biotechnology Advances. 27 (6), 811-832 (2009).</li><li>Tremblay, R., Wang, D., Jevnikar, A. M., Ma, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tobacco,+a+highly+efficient+green+bioreactor+for+production+of+therapeutic+proteins.">Tobacco, a highly efficient green bioreactor for production of therapeutic proteins.</a> Biotechnology Advances. 28 (2), 214-221 (2010).</li><li>Lee, T. M., Farrow, M. F., Arnold, F. H., Mayo, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+structural+study+of+Hypocrea+jecorina+Cel5A.">A structural study of Hypocrea jecorina Cel5A.</a> Protein Science. 20, 1935-1940 (2011).</li><li>Saloheimo, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EGIII,+a+new+endoglucanase+from+Trichoderma+reesei:+the+characterization+of+both+gene+and+enzyme.">EGIII, a new endoglucanase from Trichoderma reesei: the characterization of both gene and enzyme.</a> Gene. 63, 11-21 (1988).</li><li>Davidson, M. W., Campbell, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineered+fluorescent+proteins:+innovations+and+applications.">Engineered fluorescent proteins: innovations and applications.</a> Nature Methods. 6, 713-717 (2009).</li><li>Pelham, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+retention+signal+for+soluble+proteins+of+the+endoplasmic+reticulum.">The retention signal for soluble proteins of the endoplasmic reticulum.</a> Trends in Biochemical Sciences. 15, 483-486 (1990).</li><li>B&#233;guin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+cellulase+activity+in+polyacrylamide+gels+using+Congo+red-stained+agar+replicas.">Detection of cellulase activity in polyacrylamide gels using Congo red-stained agar replicas.</a> Analytical Biochemistry. 131, 333-336 (1983).</li><li>J&#248;rgensen, H., M&#248;rkeberg, A., Krogh, K. B. R., Olsson, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+and+enzyme+production+by+three+Penicillium+species+on+monosaccharides.">Growth and enzyme production by three Penicillium species on monosaccharides.</a> Journal of Biotechnology. 109, 295-299 (2004).</li><li>Lever, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+reaction+for+colorimetric+determination+of+carbohydrates.">A new reaction for colorimetric determination of carbohydrates.</a> Analytical Biochemistry. 47, 273-279 (1972).</li><li>Maclean, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+human+papillomavirus+type+16+(HPV-16)+L1+expression+in+plants:+comparison+of+the+suitability+of+different+HPV-16+L1+gene+variants+and+different+cell-compartment+localization.">Optimization of human papillomavirus type 16 (HPV-16) L1 expression in plants: comparison of the suitability of different HPV-16 L1 gene variants and different cell-compartment localization.</a> Journal of General Virology. 88, 1460-1469 (2007).</li><li>Munro, S., Pelham, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+C-terminal+signal+prevents+secretion+of+luminal+ER+proteins.">A C-terminal signal prevents secretion of luminal ER proteins.</a> Cell. 48, 899-907 (1987).</li><li>Laemmli, U. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cleavage+of+structural+proteins+during+the+assembly+of+the+head+of+bacteriophage+T4.">Cleavage of structural proteins during the assembly of the head of bacteriophage T4.</a> Nature. 227, 680-685 (1970).</li><li>Burnette, W. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=&#8220;Western+Blotting&#8221;:+Electrophoretic+transfer+of+proteins+from+sodium+dodecyl+sulfate-polyacrylamide+gels+to+unmodified+nitrocellulose+and+radiographic+detection+with+antibody+and+radioiodinated+protein+A.">&#8220;Western Blotting&#8221;: Electrophoretic transfer of proteins from sodium dodecyl sulfate-polyacrylamide gels to unmodified nitrocellulose and radiographic detection with antibody and radioiodinated protein A.</a> Analytical Biochemistry. 112, 195-203 (1981).</li><li>Towbin, H., Staehelin, T., Gordon, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elelctrophoretic+transfer+of+proteins+from+polyacrylamide+gels+to+nitrocellulose+sheets+-+procedure+and+some+applications.">Elelctrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets - procedure and some applications.</a> Proceedings of the National Academy of Sciences of the United States of America. 76, 4350-4354 (1979).</li><li>Blake, M. S., Johnston, K. H., Russell-Jones, G. J., Gotschlich, E. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+rapid,+sensitive+method+for+detection+of+alkaline+phosphatase-conjugated+anti-antibody+on+Western+blots.">A rapid, sensitive method for detection of alkaline phosphatase-conjugated anti-antibody on Western blots.</a> Analytical Biochemistry. 136, 175-179 (1984).</li><li>Yamamoto, E., Yamaguchi, S., Nagamune, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+&#946;-cyclodextrin+on+the+renaturation+of+enzymes+after+sodium+dodecyl+sulfate&#8211;polyacrylamide+gel+electrophoresis.">Effect of &#946;-cyclodextrin on the renaturation of enzymes after sodium dodecyl sulfate&#8211;polyacrylamide gel electrophoresis.</a> Analytical Biochemistry. 381, 273-275 (2008).</li><li>Fischer, R., Vaquero-Martin, C., Sack, M., Drossard, J., Emans, N., Commandeur, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Towards+molecular+farming+in+the+future:+transient+protein+expression+in+plants.">Towards molecular farming in the future: transient protein expression in plants.</a> Biotechnology and Applied Biochemistry. 30 (2), 113-116 (1999).</li><li>Sammond, D. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellulase+linkers+are+optimized+based+on+domain+type+and+function:+Insights+from+sequence+analysis,+biophysical+measurements,+and+molecular+simulation.">Cellulase linkers are optimized based on domain type and function: Insights from sequence analysis, biophysical measurements, and molecular simulation.</a> PLoS One. 7, (2012).</li><li>Boonvitthya, N., Bozonnet, S., Burapatana, V., O'Donohue, M. J., Chulalaksananukul, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+the+heterologous+expression+of+Trichoderma+reesei+endoglucanase+II+and+cellobiohydrolase+II+in+the+yeasts+Pichia+pastoris+and+Yarrowia+lipolytica.">Comparison of the heterologous expression of Trichoderma reesei endoglucanase II and cellobiohydrolase II in the yeasts Pichia pastoris and Yarrowia lipolytica.</a> Molecular Biotechnology. 54, 158-169 (2013).</li></ol>

Recombinant expression of cellulases is a field of great interest, due to the desire for more efficient biofuel production systems1. Plants offer many possibilities for successful cellulase production, with features such as economic harvesting techniques and autohydrolysis methods being very desirable properties for large-scale biofuel production. Further, the use of different localizations for producing proteins allow, if required, posttranslational modifications20. Altering plants to enable consti...

Degradation of lignocellulosic biomass and its conversion into liquid fuel has been envisioned as a method to reduce reliance on fossil fuels. One significant hurdle in establishing economically feasible biomass processing systems is in the enzymatic degradation of cellulose and hemicellulose1. Plant expression systems show great potential for the production of enzymes on an industrial scale. Agricultural systems to harvest plants economically and in volume are already established, as they have been for thousands of years. The production of cellulases in plants is desirable due to factors like the ease of autohydrolysis2, and the potential for maximizing the use of lower enzyme levels by increasing the digestibility of plant cell walls1. Finally, plant systems allow the targeting of recombinant proteins to specific areas of plant cells and are able to posttranslationally modify enzymes where required3.

Nicotiana tabacum (tobacco) is very commonly used as a model organism for heterologous protein expression studies in plants, due to its rapid growth and biomass accumulation features4. Transient expression of recombinant proteins is a technique which enables protein production in short time periods5, while maintaining flexibility as to the localization and thus posttranslational modifications of the selected proteins, i.e. cellulases. This enables the production of the cellulase(s) for basic analysis, while also laying the groundwork for further expression strategies in plants. Using such a transient expression strategy, an endoglucanase from glycosyl hydrolase family 5, Cel5A, derived from the fungal host Trichoderma reesei (Hypocrea jecorina)6 is produced (hereafter referred to as TrCel5A). TrCel5A is a 42 kDa protein which is natively glycosylated and is highly active in hydroylzing cellulose chains7.

The transient expression technique described here is based on a relatively commonly used system, infiltrating the plant leaves with Agrobacteria carrying the gene of interest in an appropriate expression vector. To allow for rapid analysis of successful in planta expression, TrCel5A can also be expressed as a fusion protein with mCherry, a monomeric fluorescent protein originally derived from Discosoma sp. protein DsRed8, with an additional six Histidine residues (His-tag) fused to the C-terminus (TrCel5A-mCherry). Expression of the heterologous fusion protein, TrCel5A-mCherry, can thus be monitored within the growing plant by using green light to examine mCherry dispersal. If desired, thin sections of the plant material can be examined under green light microscopically to establish the specific localization of the protein. For this work, signal and transit peptides were incorporated in the construct, to localize the heterologous protein export to the endoplasmic reticulum9.

To analyze the activity of plant expressed cellulases, including TrCel5A, a number of cellulase activity tests can be run. After the extraction of the total soluble plant proteins, TrCel5A can be partially purified using a thermal incubation technique. Protein size is established using SDS-PAGE followed by Western blotting. Zymography can be used to analyze activity against substrates, e.g. cellulose which has been carboxy-methylated (making carboxymethyl cellulose: CMC) for solubility10. Cellulase and glucosidase activity can be monitored using the fluorophore 4-methylumbelliferyl (4-MU) associated with &#946;-D-cellobioside (combined: 4-MUC). Another method to assess endoglucanase activity involves the spectrometric analysis of CMC&#160;which has been associated with an azo-dye (Remazolbrilliant Blue R)11. In addition, protein activity of both endoglucanases and a range of cellulases can be monitored by the use of a sugar analysis test, such as the p-hydroxy benzoic acid hydrazide (PAHBAH) assay12. These techniques can be used to elucidate and quantify the activity of the expressed cellulase of interest.

<table border="0" cellpadding="0" cellspacing="0" width="823">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:308px;">4-methylumbelliferyl &#946;-D-cellobioside</td>
			<td style="width:127px;">SIGMA-ALDRICH</td>
			<td style="width:156px;">M6018</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Acetic acid</td>
			<td>ROTH</td>
			<td>3738</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Acetosyringon (concentrated)</td>
			<td>ROTH</td>
			<td>6003</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Antibiotic - kanamycin</td>
			<td>ROTH</td>
			<td>T832</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Antibiotic - rifampicin</td>
			<td>ROTH</td>
			<td>4163</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Antibiotic - carbenicillin</td>
			<td>ROTH</td>
			<td>6344</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Antibody - rabbit anti His(6) pAb</td>
			<td>ROCKLAND</td>
			<td>600-401-382</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Antibody - goat anti rabbit AP, FC pAb</td>
			<td>DIANOVA</td>
			<td>111-055-008</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Azo-carboxymethyl cellulose</td>
			<td>MEGAZYME</td>
			<td>S-ACMC</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">&#946;-cyclodextrin</td>
			<td>SIGMA-ALDRICH</td>
			<td>C4805</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Calcium chloride dihydrate</td>
			<td>SIGMA-ALDRICH</td>
			<td>C5080</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Carboxymethyl cellulose</td>
			<td>ROTH</td>
			<td>3333.1</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Cellulase from Trichoderma reesei ATCC 26921</td>
			<td>SIGMA-ALDRICH</td>
			<td>C2730</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Congo red</td>
			<td>SIGMA-ALDRICH</td>
			<td>75768</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Coomasie brilliant blue G 250</td>
			<td>ROTH</td>
			<td>9598.2</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">D(+)-glucose</td>
			<td>ROTH</td>
			<td>8337</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Ethanol</td>
			<td>ROTH</td>
			<td>K928</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Filter paper - Rotilabo blotting paper</td>
			<td>ROTH</td>
			<td>CL67</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">NBT/BCIP</td>
			<td>SIGMA-ALDRICH</td>
			<td>72091</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">MES buffer</td>
			<td>ROTH</td>
			<td>4256</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Methanol</td>
			<td>ROTH</td>
			<td>8388</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sodium citrate</td>
			<td>ROTH</td>
			<td>3580</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sodium dodecylsulfate</td>
			<td>SERVA</td>
			<td>20765</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sodium hydroxide</td>
			<td>ROTH</td>
			<td>6771</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Soil, Einheitserde classic&#160;</td>
			<td>PATZER GMBH</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Spectrometer - Infinite M200</td>
			<td>TECAN</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sucrose</td>
			<td>SIGMA-ALDRICH</td>
			<td>S-5390</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">4-Hydroxy benzhydrazide&#160;</td>
			<td>SIGMA-ALDRICH</td>
			<td>H9882</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Phosphate buffered saline</td>
			<td>ROTH</td>
			<td>1058</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">UV light source - BLAK RAY</td>
			<td>UVP</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Vibratome - VT1000S</td>
			<td>Leica</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

expression of recombinant cellulase cel5a from trichoderma reesei in tobacco plants

Cellulose degrading enzymes, cellulases, are targets of both research and industrial interests. The preponderance of these enzymes in difficult-to-culture organisms, such as hyphae-building fungi and anaerobic bacteria, has hastened the use of recombinant technologies in this field. Plant expression methods are a desirable system for large-scale production of enzymes and other industrially useful proteins. Herein, methods for the transient expression of a fungal endoglucanase, Trichoderma reesei Cel5A, in Nicotiana tabacum are demonstrated. Successful protein expression is shown, monitored by fluorescence using an mCherry-enzyme fusion protein. Additionally, a set of basic tests are used to examine the activity of transiently expressed T. reesei Cel5A, including SDS-PAGE, Western blotting, zymography, as well as&#160;fluorescence and dye-based substrate degradation assays. The system described here can be used to produce an active cellulase in a short time period, so as to assess the potential for further production in plants through constitutive or inducible expression systems.

TrCel5A and TrCel5A-mCherry were expressed successfully in tobacco plants using the transient expression system (Figures 1A and 1B). Examination of the expression pattern of the TrCel5A-mCherry fusion protein revealed healthy leaves (Figure 1C), which showed widespread protein expression under green light (Figure 1D).
Extraction of the total soluble proteins was performed on tobacco plants which had leaves that contained the t...

Watch this Scientific Journal Video about Expression of Recombinant Cellulase Cel5A from Trichoderma reesei in Tobacco Plants at JoVE.com

Expression of Recombinant Cellulase Cel5A from Trichoderma reesei in Tobacco Plants

Tobacco plants were used to produce a fungal cellulase, TrCel5A, via a transient expression system. The expression could be monitored using a fluorescent fusion protein, and the protein activity was characterized post-expression.

Expression of Recombinant Cellulase Cel5A from Trichoderma reesei in Tobacco Plants

Cellulose degrading enzymes, cellulases, are targets of both research and industrial interests. The preponderance of these enzymes in difficult-to-culture ...

expression-recombinant-cellulase-cel5a-from-trichoderma-reesei

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Transient Gene Expression in Tobacco using Gibson Assembly and the Gene Gun

In order to target a single protein to multiple subcellular organelles, plants typically duplicate the relevant genes, and express each gene separately using complex regulatory strategies including differential promoters and/or signal sequences. Metabolic engineers and synthetic biologists interested in targeting enzymes to a particular organelle are faced with a challenge: For a protein that is to be localized to more than one organelle, the engineer must clone the same gene multiple times. This work presents a solution to this strategy: harnessing alternative splicing of mRNA. This technology takes advantage of established chloroplast and peroxisome targeting sequences and combines them into a single mRNA that is alternatively spliced. Some splice variants are sent to the chloroplast, some to the peroxisome, and some to the cytosol. Here the system is designed for multiple-organelle targeting with alternative splicing. In this work, GFP was expected to be expressed in the chloroplast, cytosol, and peroxisome by a series of rationally designed 5&#8217; mRNA tags. These tags have the potential to reduce the amount of cloning required when heterologous genes need to be expressed in multiple subcellular organelles. The constructs were designed in previous work11, and were cloned using Gibson assembly, a ligation independent cloning method that does not require restriction enzymes. The resultant plasmids were introduced into Nicotiana benthamiana epidermal leaf cells with a modified Gene Gun protocol. Finally, transformed leaves were observed with confocal microscopy.

This work describes a novel method for selectively targeting subcellular organelles in plants, assayed using the BioRad Gene Gun.

In order to target a single protein to multiple subcellular organelles, plants typically duplicate the relevant genes, and express each gene separately ...

Transcript and Metabolite Profiling for the Evaluation of Tobacco Tree and Poplar as Feedstock for the Bio-based Industry

The global demand for food, feed, energy, and water poses extraordinary challenges for future generations. It is evident that robust platforms for the exploration of renewable resources are necessary to overcome these challenges. Within the multinational framework MultiBioPro we are developing biorefinery pipelines to maximize the use of plant biomass. More specifically, we use poplar and tobacco tree (Nicotiana glauca) as target crop species for improving saccharification, isoprenoid, long chain hydrocarbon contents, fiber quality, and suberin and lignin contents. The methods used to obtain these outputs include GC-MS, LC-MS and RNA sequencing platforms. The metabolite pipelines are well established tools to generate these types of data, but also have the limitations in that only well characterized metabolites can be used. The deep sequencing will allow us to include all transcripts present during the developmental stages of the tobacco tree leaf, but has to be mapped back to the sequence of Nicotiana tabacum. With these set-ups, we aim at a basic understanding for underlying processes and at establishing an industrial framework to exploit the outcomes. In a more long term perspective, we believe that data generated here will provide means for a sustainable biorefinery process using poplar and tobacco tree as raw material. To date the basal level of metabolites in the samples have been analyzed and the protocols utilized are provided in this article.

Plant biomass offers a renewable resource for multiple products, including fuel, feed, food, and a variety of materials. In this paper we investigate the properties of tobacco tree (Nicotiana glauca) and poplar as suitable sources for a biorefinery pipeline.

The global demand for food, feed, energy, and water poses extraordinary challenges for future generations. It is evident that robust platforms for the ...

Measuring Fluxes of Mineral Nutrients and Toxicants in Plants with Radioactive Tracers

Unidirectional influx and efflux of nutrients and toxicants, and their resultant net fluxes, are central to the nutrition and toxicology of plants. Radioisotope tracing is a major technique used to measure such fluxes, both within plants, and between plants and their environments. Flux data obtained with radiotracer protocols can help elucidate the capacity, mechanism, regulation, and energetics of transport systems for specific mineral nutrients or toxicants, and can provide insight into compartmentation and turnover rates of subcellular mineral and metabolite pools. Here, we describe two major radioisotope protocols used in plant biology: direct influx (DI) and compartmental analysis by tracer efflux (CATE). We focus on flux measurement of potassium (K+) as a nutrient, and ammonia/ammonium (NH3/NH4+) as a toxicant, in intact seedlings of the model species barley (Hordeum vulgare L.). These protocols can be readily adapted to other experimental systems (e.g., different species, excised plant material, and other nutrients/toxicants). Advantages and limitations of these protocols are discussed.

In planta measurement of nutrient and toxicant fluxes is essential to the study of plant nutrition and toxicity. Here, we cover radiotracer protocols for influx and efflux determination in intact plant roots, using potassium (K+) and ammonia/ammonium (NH3/NH4+) fluxes as examples. Advantages and limitations of such techniques are discussed.

Unidirectional influx and efflux of nutrients and toxicants, and their resultant net fluxes, are central to the nutrition and toxicology of plants. ...

The Use of High-resolution Infrared Thermography (HRIT) for the Study of Ice Nucleation and Ice Propagation in Plants

Freezing events that occur when plants are actively growing can be a lethal event, particularly if the plant has no freezing tolerance. Such frost events often have devastating effects on agricultural production and can also play an important role in shaping community structure in natural populations of plants, especially in alpine, sub-arctic, and arctic ecosystems. Therefore, a better understanding of the freezing process in plants can play an important role in the development of methods of frost protection and understanding mechanisms of freeze avoidance. Here, we describe a protocol to visualize the freezing process in plants using high-resolution infrared thermography (HRIT). The use of this technology allows one to determine the primary sites of ice formation in plants, how ice propagates, and the presence of ice barriers. Furthermore, it allows one to examine the role of extrinsic and intrinsic nucleators in determining the temperature at which plants freeze and evaluate the ability of various compounds to either affect the freezing process or increase freezing tolerance. The use of HRIT allows one to visualize the many adaptations that have evolved in plants, which directly or indirectly impact the freezing process and ultimately enables plants to survive frost events.

The Use of High-resolution Infrared Thermography HRIT for the Study of Ice Nucleation and Ice Propagation in Plants

Here we present a protocol that allows one to visualize sites of ice formation and avenues of ice propagation in plants utilizing high resolution infrared thermography (HRIT).

Freezing events that occur when plants are actively growing can be a lethal event, particularly if the plant has no freezing tolerance. Such frost events ...

RNAi-mediated Control of Aflatoxins in Peanut: Method to Analyze Mycotoxin Production and Transgene Expression in the Peanut/Aspergillus Pathosystem

The Food and Agriculture Organization of the United Nations estimates that 25% of the food crops in the world are contaminated with aflatoxins. That represents 100 million tons of food being destroyed or diverted to non-human consumption each year. Aflatoxins are powerful carcinogens normally accumulated by the fungi Aspergillus flavus and A. parasiticus in cereals, nuts, root crops and other agricultural products. Silencing of five aflatoxin-synthesis genes by RNA interference (RNAi) in peanut plants was used to control aflatoxin accumulation following inoculation with A. flavus. Previously, no method existed to analyze the effectiveness of RNAi in individual peanut transgenic events, as these usually produce few seeds, and traditional methods of large field experiments under aflatoxin-conducive conditions were not an option. In the field, the probability of finding naturally contaminated seeds is often 1/100 to 1/1,000. In addition, aflatoxin contamination is not uniformly distributed. Our method uses few seeds per transgenic event, with small pieces processed for real-time PCR (RT-PCR) or small RNA sequencing, and for analysis of aflatoxin accumulation by ultra-performance liquid chromatography (UPLC). RNAi-expressing peanut lines 288-72 and 288-74, showed up to 100% reduction (p&#8804;0.01) in aflatoxin B1 and B2 compared to the control that accumulated up to 14,000 ng.g-1 of aflatoxin B1 when inoculated with aflatoxigenic A. flavus. As reference, the maximum total of aflatoxins allowable for human consumption in the United States is 20 ng.g-1. This protocol describes the application of RNAi-mediated control of aflatoxins in transgenic peanut seeds and methods for its evaluation. We believe that its application in breeding of peanut and other crops will bring rapid advancement in this important area of science, medicine and human nutrition, and will significantly contribute to the international effort to control aflatoxins, and potentially other mycotoxins in major food crops.

RNAi-mediated Control of Aflatoxins in Peanut: Method to Analyze Mycotoxin Production and Transgene Expression in the Peanut/Aspergillus Pathosystem

We demonstrate a method for the analysis of aflatoxins and transgene expression in peanut seeds that contain RNA-interference signals for silencing aflatoxin-synthesis genes in the fungus Aspergillus flavus. RNAi-mediated control of mycotoxins in plants has not been reported previously.

The Food and Agriculture Organization of the United Nations estimates that 25% of the food crops in the world are contaminated with aflatoxins. That ...

Enhancement of the Initial Growth Rate of Agricultural Plants by Using Static Magnetic Fields

Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing seeds of Garden Balsam (Impatiens balsamina), Mizuna (Brassica rapa var. japonica), Komatsuna (Brassica rapa var. perviridis), and Mescluns (Lepidium sativum). We applied magnets under the culture dish. During the 4 days of application, we observed that the stem and root length increased. The group subjected to magnetic field treatment (n = 10) showed a 1.4 times faster rate of growth compared with the control group (n = 11) in a total of 8 days (p &#60;0.0005). This rate is 20% higher than that reported in previous studies. The tubulin complex lines did not have connecting points, but connecting points occur upon the application of magnets. This shows complete difference from the control, which means abnormal arrangements. However, the exact cause remains unclear. These results of growth enhancement of applying magnets suggest that it is possible to enhance the growth rate, increase productivity, or control the speed of germination of plants by applying static magnetic fields. Also, magnetic fields can cause physiological changes in plant cells and can induce growth. Therefore, stimulation with a magnetic field can have possible effects that are similar to those of chemical fertilizers, which means that the use of fertilizers can be avoided.

The goal of this protocol is to demonstrate the acceleration of the initial growth rate of plants by applying static magnetic fields with no external energy.

Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing ...

Assessment of Methane and Nitrous Oxide Fluxes from Paddy Field by Means of Static Closed Chambers Maintaining Plants Within Headspace

This protocol describes the measurement of greenhouse gas (GHG) emissions from paddy soils using the static closed chamber technique. This method is based on the diffusion theory. A known volume of air overlaying a defined soil area is enclosed within a parallelepiped cover (named &#34;chamber&#34;), for a defined period of time. During this enclosure period, gases (methane (CH4) and nitrous oxide (N2O)) move from soil pore air near their microbial source (i.e., methanogens, nitrifiers, denitrifiers) to the chamber headspace, following a natural concentration gradient. Fluxes are then estimated from chamber headspace concentration variations sampled at regular intervals throughout the enclosure and then analyzed with gas chromatography. Among the techniques available for GHG measurement, the static closed chamber method is suitable for plot experiments, as it does not require large homogenously treated soil areas. Furthermore, it is manageable with limited resources and can identify relationships among ecosystem properties, processes, and fluxes, especially when combined with GHG driving force measurements. Nevertheless, with respect to the micrometeorological method, it causes a minimal but still unavoidable soil disturbance, and allows a minor temporal resolution. Several phases are key to the method implementation: i) chamber design and deployment, ii) sample handling and analyses, and iii) flux estimation. Technique implementation success in paddy fields demands adjustments for field flooding during much of the cropping cycle, and for rice plant maintenance within the chamber headspace during measurements. Therefore, the additional elements to be considered with respect to the usual application of non-flooded agricultural soils consist of devices for: i) avoiding any unintended water disturbance that could overestimate fluxes, and ii) including rice plants within the chamber headspace to fully consider gases emitted through aerenchyma transportation.

The overall goal of this protocol is to measure greenhouse gas emissions from paddy fields using the static closed chamber technique. The measurement system needs specific adjustments due to the presence of both a permanent water layer in the field and of the plants within the chamber headspace.

This protocol describes the measurement of greenhouse gas (GHG) emissions from paddy soils using the static closed chamber technique. This method is based ...

Protocol for Producing Three-Dimensional Infrared Video of Freezing in Plants

Freezing in plants can be monitored using infrared (IR) thermography, because when water freezes, it gives off heat. However, problems with color contrast make 2-dimensions (2D) infrared images somewhat difficult to interpret. Viewing an IR image or the video of plants freezing in 3 dimensions (3D) would allow a more accurate identification of sites for ice nucleation as well as the progression of freezing. In this paper, we demonstrate a relatively simple means to produce a 3D infrared video of a strawberry plant freezing. Strawberry is an economically important crop that is subjected to unexpected spring freeze events in many areas of the world. An accurate understanding of the freezing in strawberry will provide both breeders and growers with more economical ways to prevent any damage to plants during freezing conditions.
The technique involves a positioning of two IR cameras at slightly different angles to film the strawberry freezing. The two video streams will be precisely synchronized using a screen capture software that records both cameras simultaneously. The recordings will then be imported into the imaging software and processed using an anaglyph technique. Using red-blue glasses, the 3D video will make it easier to determine the precise site of ice nucleation on leaf surfaces.

Here, we present a protocol to image a strawberry plant freezing in 3 dimensions. Two infrared cameras positioned at slightly different angles are used to produce a red-blue anaglyph video to observe the freezing of the plant in 3 dimensions.

Freezing in plants can be monitored using infrared (IR) thermography, because when water freezes, it gives off heat. However, problems with color contrast ...

A Loop-mediated Isothermal Amplification (LAMP) Assay for Rapid Identification of Bemisia tabaci

The whitefly Bemisia tabaci (Gennadius) is an invasive pest of considerable importance, affecting the production of vegetable and ornamental crops in many countries around the world. Severe yield losses are caused by direct feeding, and even more importantly, also by the transmission of more than 100 harmful plant pathogenic viruses. As for other invasive pests, increased international trade facilitates the dispersal of B. tabaci to areas beyond its native range. Inspections of plant import products at points of entry such as seaports and airports are, therefore, seen as an important prevention measure. However, this last line of defense against pest invasions is only effective if rapid identification methods for suspicious insect specimens are readily available. Because the morphological differentiation between the regulated B. tabaci and close relatives without quarantine status is difficult for non-taxonomists, a rapid molecular identification assay based on the loop-mediated isothermal amplification (LAMP) technology has been developed. This publication reports the detailed protocol of the novel assay describing rapid DNA extraction, set-up of the LAMP reaction, as well as interpretation of its read-out, which allows identifying B. tabaci specimens within one hour. Compared to existing protocols for the detection of specific B. tabaci biotypes, the developed method targets the whole B. tabaci species complex in one assay. Moreover the assay is designed to be applied on-site by plant health inspectors with minimal laboratory training directly at points of entry. Thorough validation performed under laboratory and on-site conditions demonstrates that the reported LAMP assay is a rapid and reliable identification tool, improving the management of B. tabaci.

A Loop-mediated Isothermal Amplification LAMP Assay for Rapid Identification of Bemisia tabaci

This paper reports the protocol for a rapid identification assay for Bemisia tabaci based on loop-mediated isothermal amplification (LAMP) technology. The protocol requires minimal laboratory training and can, therefore, be implemented on-site at points of entry for plant imports such as seaports and airports.

The whitefly Bemisia tabaci (Gennadius) is an invasive pest of considerable importance, affecting the production of vegetable and ornamental crops in many ...

Detached Leaf Assays to Simplify Gene Expression Studies in Potato During Infestation by Chewing Insect Manduca sexta

The multitrophic nature of gene expression studies of insect herbivory demands large numbers of biological replicates, creating the need for simpler, more streamlined herbivory protocols. Perturbations of chewing insects are usually studied in whole plant systems. While this whole organism strategy is popular, it is not necessary if similar observations can be replicated in a single detached leaf. The assumption is that basic elements required for signal transduction are present within the leaf itself. In the case of early events in signal transduction, cells need only to receive the signal from the perturbation and transmit that signal to neighboring cells which are assayed for gene expression.
The proposed method simply changes the timing of the detachment. In whole plant experiments, larvae are confined to a single leaf which is eventually detached from the plant and assayed for gene expression. If the order of excision is reversed, from last in whole plant studies, to first in the detached study, the feeding experiment is simplified.
Solanum tuberosum var. Kennebec is propagated by nodal transfer in a simple tissue culture medium and transferred to soil for further growth if desired. Leaves are excised from the parent plant and relocated to Petri dishes where the feeding assay is conducted with the larval stages of M. sexta. Damaged leaf tissue is assayed for the expression of relatively early events in signal transduction. Gene expression analysis identified infestation-specific Cys2-His2 (C2H2) transcription factors, confirming the success of using detached leaves in early response studies. The method is easier to perform than whole plant infestations and uses less space.

The presented method creates natural herbivore damaged plant tissue through the application of Manduca sexta larvae to detached leaves of potato. The plant tissue is assayed for expression of six transcription factor homologs involved in early responses to insect herbivory.

The multitrophic nature of gene expression studies of insect herbivory demands large numbers of biological replicates, creating the need for simpler, more ...