Name: using ustilago maydis as a trojan horse for in situ delivery of maize proteins
Uploaded: 2019-02-08T13:00:00
Description: Watch this Scientific Journal Video about Using Ustilago maydis as a Trojan Horse for In Situ Delivery of Maize Proteins at JoVE.com

The authors would like to thank Thomas Dresselhaus, Martin Parniske, Noureddine Djella, and Armin Hildebrand for providing lab space and plant material. The original work on the Trojan horse method was supported by a Leopoldina postdoc fellowship and NSF project IOS13-39229. The work presented in this article was supported by SFB924 (projects A14 and B14) of the DFG.

1. Construction of an U. maydis Trojan Horse
NOTE: See Figure 1.
<ol>
	<li>Amplify a gene of interest from maize cDNA using gene-specific primers and a proofreading DNA polymerase. Clone the primary PCR product and transform the construct into E. coli following the plasmid vendor&#39;s instructions. Verify the correct gene of interest sequence by Sanger sequencing prior to use for the next cloning steps. 
	<strong...

<ol>
	<li>K&#228;mper, 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=Insights+from+the+genome+of+the+biotrophic+fungal+plant+pathogen+Ustilago+maydis.">Insights from the genome of the biotrophic fungal plant pathogen Ustilago maydis.</a> Nature. 444, 97-101 (2006).</li><li>Doehlemann, G., 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=Establishment+of+compatibility+in+the+Ustilago+maydis/maize+pathosystem.">Establishment of compatibility in the Ustilago maydis/maize pathosystem.</a> Journal of Plant Physiology. 165, 29-40 (2008).</li><li>Matei, A., 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=How+to+make+a+tumour:+cell+type+specific+dissection+of+Ustilago+maydis-induced+tumour+development+in+maize+leaves.">How to make a tumour: cell type specific dissection of Ustilago maydis-induced tumour development in maize leaves.</a> New Phytologist. , (2018).</li><li>Doehlemann, G., 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=Reprogramming+a+maize+plant:+transcriptional+and+metabolic+changes+induced+by+the+fungal+biotroph+Ustilago+maydis.">Reprogramming a maize plant: transcriptional and metabolic changes induced by the fungal biotroph Ustilago maydis.</a> The Plant Journal. 56, 181-195 (2008).</li><li>Doehlemann, G., 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=Pep1,+a+secreted+effector+protein+of+Ustilago+maydis.,+is+required+for+successful+invasion+of+plant+cells.">Pep1, a secreted effector protein of Ustilago maydis., is required for successful invasion of plant cells.</a> PLOS Pathogens. 5, e1000290 (2009).</li><li>Redkar, A., 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=A+secreted+effector+protein+of+Ustilago+maydis+guides+maize+leaf+cells+to+form+tumors.">A secreted effector protein of Ustilago maydis guides maize leaf cells to form tumors.</a> The Plant Cell. 27, 1332-1351 (2015).</li><li>Djamei, A., 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=Metabolic+priming+by+a+secreted+fungal+effector.">Metabolic priming by a secreted fungal effector.</a> Nature. 478, 395-398 (2011).</li><li>Tanaka, S., 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=A+secreted+Ustilago+maydis+effector+promotes+virulence+by+targeting+anthocyanin+biosynthesis+in+maize.">A secreted Ustilago maydis effector promotes virulence by targeting anthocyanin biosynthesis in maize.</a> eLife. 3, e01355 (2014).</li><li>Mueller, A. N., Ziemann, S., Treitschke, S., Assmann, D., Doehlemann, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Compatibility+in+the+Ustilago+maydis-maize+interaction+requires+inhibition+of+host+cysteine+proteases+by+the+fungal+effector+Pit2.">Compatibility in the Ustilago maydis-maize interaction requires inhibition of host cysteine proteases by the fungal effector Pit2.</a> PLOS Pathogens. 9, e1003177 (2013).</li><li>Ziemann, S., 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=An+apoplastic+peptide+activates+salicylic+acid+signalling+in+maize.">An apoplastic peptide activates salicylic acid signalling in maize.</a> Nature Plants. 4, 172-180 (2018).</li><li>Ju&#225;rez-Montiel, 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=The+corn+smut+('Huitlacoche')+as+a+new+platform+for+oral+vaccines.">The corn smut ('Huitlacoche') as a new platform for oral vaccines.</a> PLoS One. 10, e0133535 (2015).</li><li>Sarkari, P., Feldbr&#252;gge, M., Schipper, K., Schmoll, M., Dattenb&#246;ck, 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> Gene Expression Systems in Fungi: Advancements and Applications. , 183-200 (2016).</li><li>Monreal-Escalante, E., 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=The+corn+smut-made+cholera+oral+vaccine+is+thermostable+and+induces+long-lasting+immunity+in+mouse.">The corn smut-made cholera oral vaccine is thermostable and induces long-lasting immunity in mouse.</a> Journal of Biotechnology. 234, 1-6 (2016).</li><li>Stock, 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=Applying+unconventional+secretion+of+the+endochitinase+Cts1+to+export+heterologous+proteins+in+Ustilago+maydis.">Applying unconventional secretion of the endochitinase Cts1 to export heterologous proteins in Ustilago maydis.</a> Journal of Biotechnology. 161, 80-91 (2012).</li><li>van der Linde, K., 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=Pathogen+Trojan+horse+delivers+bioactive+host+protein+to+alter+maize+(Zea+mays)+anther+cell+behavior+in+situ.">Pathogen Trojan horse delivers bioactive host protein to alter maize (Zea mays) anther cell behavior in situ.</a> The Plant Cell. 30, 528-542 (2018).</li><li>B&#246;sch, K., 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=Genetic+manipulation+of+the+plant+pathogen+Ustilago+maydis+to+study+fungal+biology+and+plant+microbe+interactions.">Genetic manipulation of the plant pathogen Ustilago maydis to study fungal biology and plant microbe interactions.</a> Journal of Visualized Experiments. , e54522 (2016).</li><li>Chavan, S., Smith, S. 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+rapid+and+efficient+method+for+assessing+pathogenicity+of+Ustilago+maydis+on+maize+and+teosinte+lines.">A rapid and efficient method for assessing pathogenicity of Ustilago maydis on maize and teosinte lines.</a> Journal of Visualized Experiments. 50712, (2014).</li><li>Kelliher, T., Walbot, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emergence+and+patterning+of+the+five+cell+types+of+the+Zea+mays+anther+locule.">Emergence and patterning of the five cell types of the Zea mays anther locule.</a> Developmental Biology. 350, 32-49 (2011).</li><li>Egger, R. L., Walbot, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantifying+Zea+mays.+tassel+development+and+correlation+with+anther+developmental+stages+as+a+guide+for+experimental+studies.">Quantifying Zea mays. tassel development and correlation with anther developmental stages as a guide for experimental studies.</a> Maydica. 60, M34 (2015).</li><li>Holliday, R., King, R. 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> Bacteria, Bacteriophages, and Fungi: Volume 1. , 575-595 (1974).</li><li>Doehlemann, G., Reissmann, S., A&#223;mann, D., Fleckenstein, M., Kahmann, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two+linked+genes+encoding+a+secreted+effector+and+a+membrane+protein+are+essential+for+Ustilago+maydis-induced+tumour+formation.">Two linked genes encoding a secreted effector and a membrane protein are essential for Ustilago maydis-induced tumour formation.</a> Molecular Microbiology. 81, 751-766 (2011).</li><li>Banuett, F., Herskowitz, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Different+a+alleles+of+Ustilago+maydis+are+necessary+for+maintenance+of+filamentous+growth+but+not+for+meiosis.">Different a alleles of Ustilago maydis are necessary for maintenance of filamentous growth but not for meiosis.</a> Proceedings of the National Academy of Sciences. 86, 5878-5882 (1989).</li><li>Bortfeld, M., Auffarth, K., Kahmann, R., Basse, C. 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+Ustilago+maydis+a2+mating-type+locus+genes+lga2+and+rga2+compromise+pathogenicity+in+the+absence+of+the+mitochondrial+p32+family+protein+Mrb1.">The Ustilago maydis a2 mating-type locus genes lga2 and rga2 compromise pathogenicity in the absence of the mitochondrial p32 family protein Mrb1.</a> The Plant Cell. 16, 2233-2248 (2004).</li></ol>

Modern crop research demands protocols for molecular analysis on genetic and protein levels. Genetic accessibility via transformation is not available or inefficient and time-consuming for most crop species such as maize. Moreover, reliable genetic tools such as promoter reporter systems are scarce, which makes it difficult to study in situ protein function with high spatiotemporal resolution at distinct tissue sites. Apoplastic proteins can be studied by infiltration of heterologously expressed and purified pro...

The biotrophic pathogen Ustilago maydis is the causative agent of the corn smut disease1. It infects all aerial parts of maize resulting in large tumors that contain melanized, black spores. On the global level, U. maydis is estimated to cause an annual loss of around 2% of corn yield, while tumors are appreciated as a gastronomical delicacy in Mexico. Plant infection is initiated by an appressorium that secretes cell-wall lysing enzymes to penetrate the first layer of maize epidermal cells. From a primary infection site, U. maydis grows intracellularly and intercellularly, invading one to two cell layers every day1,2. Successful infection results in plant hypertrophy that turns into visible tumors upon five days post infection1,3,4. During all infection stages, fungal hyphae invaginate the plant cytoplasm membrane without any direct contact to the host cytoplasm1,2. The tight apoplasmic space between the infecting hyphae and the plant plasma membrane is considered to be the host/pathogen interactive site, called the biotrophic interaction zone. In order to overcome the plant innate immune system, U. maydis secretes an array of effector proteins into the biotrophic interaction zone1. Some effectors are taken up by plant cells, while others remain in the biotrophic interaction zone5,6,7,8. One apoplastic effector is UmPit2, which interacts with apoplastic maize proteases to prevent the release of the signaling peptide ZmZIP1 from ZmPROZIP by apoplastic protease activity9,10.
Over the last decades, U. maydis became not only a model for fungal genetics in plant-pathogen interaction, but also a valuable tool in biotechnology due to a well-understood life cycle, easy genetic accessibility and heterologous expression of secreted proteins11,12,13. Signals for both conventional and unconventional protein secretion have been determined allowing the control of posttranslational modifications14. Recently, U. maydis was employed as a Trojan horse tool to study small, secreted maize proteins in situ15. The Trojan horse approach was successfully used to analyze the function of the small, secreted protein ZmMAC1 that is involved in anther development. ZmMAC1 induces the periclinal division of pluripotent cells and cell fate specification of the newly formed cells15. By the same method, the biological function of the maize damage-associated peptide ZmZIP1 was revealed. U. maydis secreting the maize ZmZIP1 resulted in impaired tumor formation10. Thus, the Trojan horse approach represents a valuable alternative route to protein in situ studies with high spatiotemporal resolution that does neither require generation of stable maize transformation lines nor tissue infiltration with heterologously expressed and purified proteins. In particular, the Trojan horse strategy enables the secretion of any heterologous protein into the maize apoplast and direct comparison of infected versus non-infected plant cells within the same tissue.
This protocol illustrates the major steps for generating an U. maydis Trojan horse strain to study a protein of interest. It further includes precise information on infection procedures of three different maize tissue types (adult leaves, tassels and ears) with U. maydis, which is a prerequisite for studying the spatiotemporal infection progression and protein function in these target tissues. No further specifications are given on maize gene amplification and microscopic imaging techniques, since these steps are target-specific and instrument-dependent. Thus, this protocol is addressed to experienced users of standard molecular biology techniques.

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	<tbody>
		<tr height="22">
			<td height="22" style="height:22px;width:307px;">2 mL syringe&#160;</td>
			<td style="width:119px;">B. Braun</td>
			<td style="width:89px;">4606027V</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">23G x 1 1/4 hypodermic needle</td>
			<td style="width:119px;">B. Braun</td>
			<td>4657640</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bacto Peptone&#160;</td>
			<td style="width:119px;">BD</td>
			<td>211677</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:307px;">cDNA from maize</td>
			<td style="width:119px;"></td>
			<td style="width:89px;"></td>
			<td style="width:311px;">from maize tissue expressing the gene of interrest</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Charcoal</td>
			<td>Sigma-Aldrich</td>
			<td style="width:89px;">05105</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Confocal laser scanning microscope</td>
			<td style="width:119px;"></td>
			<td style="width:89px;"></td>
			<td style="width:311px;">use locally available equipment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:307px;">Cuvette (10 x 4 x 45 mm)</td>
			<td style="width:119px;">Sarstedt</td>
			<td style="width:89px;">67742</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Incubator-shaker set to 28 &#176;C, 200 rpm</td>
			<td style="width:119px;"></td>
			<td style="width:89px;"></td>
			<td style="width:311px;">use locally available equipment</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:307px;">Light microscope with 400-fold magnification</td>
			<td style="width:119px;"></td>
			<td style="width:89px;"></td>
			<td style="width:311px;">use locally available equipment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:307px;">Nco I</td>
			<td style="width:119px;">NEB</td>
			<td style="width:89px;">R0193</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="49">
			<td height="49" style="height:49px;">p123-PUmpit2-SpUmpit2-Zmmac1-mCherry-Ha</td>
			<td style="width:119px;"></td>
			<td style="width:89px;"></td>
			<td style="width:311px;">please contact the corresponding author&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:307px;">Pasteur pipet (glass, long tip)</td>
			<td style="width:119px;">VWR</td>
			<td>14673-043</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:307px;">pCR-Blunt-II-TOPO</td>
			<td style="width:119px;">Thermo Fisher Scientific</td>
			<td>K280002</td>
			<td style="width:311px;">can be exchanged for other basic cloning vectors like pENTR or pJET</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Potato Dextrose Agar&#160;</td>
			<td style="width:119px;">VWR</td>
			<td style="width:89px;">90000-745</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:23px;width:307px;">Sharpie pen</td>
			<td style="width:119px;"></td>
			<td style="width:89px;"></td>
			<td style="width:311px;">use locally available equipment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:307px;">Spectrophotometer</td>
			<td style="width:119px;"></td>
			<td style="width:89px;"></td>
			<td style="width:311px;">use locally available equipment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:307px;">Ssp I</td>
			<td style="width:119px;">NEB</td>
			<td style="width:89px;">R0132</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sucrose</td>
			<td>Sigma-Aldrich</td>
			<td style="width:89px;">S0389</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:307px;">T4 DNA ligase</td>
			<td style="width:119px;">NEB</td>
			<td style="width:89px;">M0202</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:307px;">TRIS</td>
			<td>Sigma-Aldrich</td>
			<td style="width:89px;">TRIS-RO</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:307px;">Xba I</td>
			<td style="width:119px;">NEB</td>
			<td style="width:89px;">R0145</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Yeast extract&#160;</td>
			<td style="width:119px;">BD</td>
			<td>212750</td>
			<td style="width:311px;"></td>
		</tr>
	</tbody>
</table>

using ustilago maydis as a trojan horse for in situ delivery of maize proteins

Inspired by Homer&#180;s Trojan horse myth, we engineered the maize pathogen Ustilago maydis to deliver secreted proteins into the maize apoplast permitting in vivo phenotypic analysis. This method does not rely on maize transformation but exploits microbial genetics and secretory capabilities of pathogens. Herein, it allows inspection of in vivo delivered secreted proteins with high spatiotemporal resolution at different kinds of infection sites and tissues. The Trojan horse strategy can be utilized to transiently complement maize loss-of-function phenotypes, to functionally characterize protein domains, to analyze off-target protein effects, or to study onside protein overdosage, making it a powerful tool for protein studies in the maize crop system. This work contains a precise protocol on how to generate a Trojan horse strain followed by standardized infection protocols to apply this method to three different maize tissue types.

Constructs for U. maydis Trojan horse experiments are cloned into the plasmid p123-PUmpit2-SpUmpit2-gene of interest-mCherry-Ha. The maize gene of interest is fused to a mCherry fluorescence reporter and an epitope HA-tag. The expression of the fusion protein is under control of the U. maydis Umpit2 promoter which is specifically activated during infection<...

Watch this Scientific Journal Video about Using Ustilago maydis as a Trojan Horse for In Situ Delivery of Maize Proteins at JoVE.com

Using Ustilago maydis as a Trojan Horse for In Situ Delivery of Maize Proteins

This work describes the cloning of an Ustilago maydis Trojan horse strain for the in situ delivery of secreted maize proteins into three different types of maize tissues.

Using Ustilago maydis as a Trojan Horse for In Situ Delivery of Maize Proteins

Inspired by Homer&#180;s Trojan horse myth, we engineered the maize pathogen Ustilago maydis to deliver secreted proteins into the maize apoplast ...

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