Name: the plant infection test: spray and wound-mediated inoculation with the plant pathogen magnaporthe grisea
Uploaded: 2018-08-04T13:30:00
Description: Watch this Scientific Journal Video about The Plant Infection Test: Spray and Wound-Mediated Inoculation with the Plant Pathogen Magnaporthe Grisea at JoVE.com

This work was supported by the Special Scientific Research Project of the Beijing Agriculture University (YQ201603) and the Scientific Project of the Beijing Educational Committee (KM201610020005).

1. Spray Inoculation with a Suspension of M. grisea Conidia
<ol>
	<li>Fungal culture for M.grisea
	<ol>
		<li>Prepare the oatmeal tomato agar (OTA) culture medium for fungal strains.</li>
		<li>Weigh 30 - 50 g of oatmeal, add this to 800 mL of distilled/deionized water (ddH2O) and boil the mixture for 30 min in the electric pot.</li>
		<li>Filter the boiled oatmeal juice into the beaker through a piece of gauze.</li>
		<li>Add 150 mL of tomato juice and 20 g of agar to the ...

<ol>
	<li>Li, W. T., 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+natural+allele+of+a+transcription+factor+in+rice+confers+broad-spectrum+blast+resistance.">A natural allele of a transcription factor in rice confers broad-spectrum blast resistance.</a> Cell. 170 (1), 114-126 (2017).</li><li>Chi, M. H., Park, S. Y., Kim, S., Lee, Y. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+pathogenicity+gene+is+required+in+the+rice+blast+fungus+to+suppress+the+basal+defenses+of+the+host.">A novel pathogenicity gene is required in the rice blast fungus to suppress the basal defenses of the host.</a> PLoS Pathogens. 5 (4), 1000401 (2009).</li><li>Jia, Y., Valent, B., Lee, F. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+host+responses+to+Magnaporthe+grisea.on+detached+rice+leaves+using+a+spot+inoculation+method.">Determination of host responses to Magnaporthe grisea.on detached rice leaves using a spot inoculation method.</a> Plant Disease. 87 (2), 129-133 (2003).</li><li>Ebbole, 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=Magnaporthe+as+a+model+for+understanding+host-pathogen+interactions.">Magnaporthe as a model for understanding host-pathogen interactions.</a> Annual Review of Phytopathology. 45, 437-456 (2007).</li><li>Hamer, J. E., Talbot, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Infection-related+development+in+the+rice+blast+fungus+Magnaporthe+grisea.">Infection-related development in the rice blast fungus Magnaporthe grisea.</a> Current Opinion in Microbiology. 1 (6), 693-697 (1998).</li><li>Howard, R. J., Valent, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Breaking+and+entering:+host+penetration+by+the+fungal+rice+blast+pathogen+Magnaporthe+grisea.">Breaking and entering: host penetration by the fungal rice blast pathogen Magnaporthe grisea.</a> Annual Review of Microbiology. 50, 491-512 (1996).</li><li>Chen, X. L., 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=N-Glycosylation+of+Effector+Proteins+by+an+&#945;-1,3-+Mannosyltransferase+Is+Required+for+the+Rice+Blast+Fungus+to+Evade+Host+Innate+Immunity.">N-Glycosylation of Effector Proteins by an &#945;-1,3- Mannosyltransferase Is Required for the Rice Blast Fungus to Evade Host Innate Immunity.</a> The Plant Cell. 26 (3), 1360-1376 (2014).</li><li>Zhang, Y., 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=M.ARG1,+MoARG5,6+and+MoARG7+involved+in+arginine+biosynthesis+are+essential+for+growth,+conidiogenesis,+sexual+reproduction,+and+pathogenicity+in+Magnaporthe+oryzae.">M.ARG1, MoARG5,6 and MoARG7 involved in arginine biosynthesis are essential for growth, conidiogenesis, sexual reproduction, and pathogenicity in Magnaporthe oryzae.</a> Microbiological Research. 180, 11-22 (2015).</li><li>Du, Y. X., 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+serine/threonine-protein+phosphatase+PP2A+catalytic+subunit+is+essential+for+asexual+development+and+plant+infection+in+Magnaporthe+oryzae.">A serine/threonine-protein phosphatase PP2A catalytic subunit is essential for asexual development and plant infection in Magnaporthe oryzae.</a> Current Genetics. 59 (1-2), 33-41 (2013).</li><li>Yang, 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=A+novel+protein+com1+is+required+for+normal+conidium+morphology+and+full+virulence+in+Magnaporthe+oryzae.">A novel protein com1 is required for normal conidium morphology and full virulence in Magnaporthe oryzae.</a> Molecular Plant-Microbe Interactions. 23 (1), 112-123 (2010).</li><li>Cao, Z. 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=An+ash1-like+protein+MoKMT2H+null+mutant+is+delayed+for+conidium+germination+and+pathogenesis+in+Magnaporthe+oryzae.">An ash1-like protein MoKMT2H null mutant is delayed for conidium germination and pathogenesis in Magnaporthe oryzae.</a> BioMed Research International. 2016, 1575430 (2016).</li><li>Bryan, G. T., 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+single+amino+acid+difference+distinguishes+resistant+and+susceptible+alleles+of+the+rice+blast+resistance+gene+Pi-ta.">A single amino acid difference distinguishes resistant and susceptible alleles of the rice blast resistance gene Pi-ta.</a> The Plant Cell. 12 (11), 2033-2045 (2000).</li><li>Zhou, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plant+pathology:+a+life+and+death+struggle+in+rice+blast+disease.">Plant pathology: a life and death struggle in rice blast disease.</a> Current Biology. 26 (18), 843-845 (2016).</li><li>Guo, 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=MoGrr1,+a+novel+F-box+protein,+is+involved+in+conidiogenesis+and+cell+wall+integrity+and+is+critical+for+the+full+virulence+of+Magnaporthe+oryzae.">MoGrr1, a novel F-box protein, is involved in conidiogenesis and cell wall integrity and is critical for the full virulence of Magnaporthe oryzae.</a> Applied Microbiology and Biotechnology. 99 (19), 8075-8088 (2015).</li><li>Talbot, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+trail+of+a+cereal+killer:+Exploring+the+biology+of+Magnaporthe+grisea.">On the trail of a cereal killer: Exploring the biology of Magnaporthe grisea.</a> Annual Review of Microbiology. 57, 177-202 (2009).</li><li>Wilson, R. A., Talbot, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Under+pressure:+investigating+the+biology+of+plant+infection+by+Magnaporthe+oryzae.">Under pressure: investigating the biology of plant infection by Magnaporthe oryzae.</a> Nature Reviews Microbiology. 7, 185-195 (2009).</li><li>Jia, Y. L., Lee, F. N., McClung, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+Resistance+Spectra+of+the+Pi-ta+and+Pi-k+Genes+to+U.S.+Races+of+Magnaporthe+oryzae+Causing+Rice+Blast+in+a+Recombinant+Inbred+Line+Population.">Determination of Resistance Spectra of the Pi-ta and Pi-k Genes to U.S. Races of Magnaporthe oryzae Causing Rice Blast in a Recombinant Inbred Line Population.</a> Plant Disease. 93, 639-644 (2009).</li><li>Peng, Y. L., Shishiyama, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+sequence+of+cytological+events+in+rice+leaves+infected+with+Pyricularia+oryzae.">Temporal sequence of cytological events in rice leaves infected with Pyricularia oryzae.</a> Canadian Journal of Botany. 66 (4), 730-735 (1988).</li></ol>

Plant disease resistance genes play an essential role in preventing infections by pathogens, including fungal pathogens1,12. Rice blast has been used as a model to understand the nature of pathogen population structures and to identify plant resistance genes4. Therefore, it is necessary to examine the disease resistance genotype and avirulence genotypes of the main varieties of agricultural plants on a large scale to identify disease-resis...

Rice blast, caused by M. grisea, is one of the most serious diseases for rice varieties worldwide1,2. The process by which M. grisea infects host plants includes a conidia production and surface attachment, a conidia germination and appressorium formation, a formation of the penetration peg and infectious hypha differentiation, and a disease spread3. All these stages are common in many other plant pathogenic fungi, and, indeed, a blockade of any single stage prevents the infection of host plants. Owing to its economic importance and genetic tractability, M. grisea has emerged as a model organism for studying the mechanisms of plant-fungal pathogen interactions1,4. Therefore, studying the molecular basis of these developmental stages in M. grisea will help to elucidate the molecular mechanisms underlying fungal pathogenicity and the identification of candidate target genes for screening and designing novel fungicides5.
Recent reports concerning M. grisea infection have focused on the molecular mechanisms of the pre-penetration stages, especially the conidiation, the appressorium formation, the penetration pegs, and the infectious growth3,6. Therefore, it is essential to develop a detailed protocol to test M. grisea infection. Herein, we present a detailed method for an infection test that utilizes spray-mediated infection assays with a conidial suspension and the inoculation of wounds with mycelial plugs of M. grisea. In this report, the protocol focuses on the culture of strains, the preparation of the conidiation solution for spraying, and the mycelial plug-mediated inoculation of plants with M. grisea. These steps are described in detail below, and a schematic view showing the entire workflow of the method and a typical lesion are shown in Figures 1 and 2, respectively.

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	<tbody>
		<tr height="77">
			<td height="77" style="height:77px;width:216px;">&#160;Agar</td>
			<td style="width:177px;">AOBOX Biotechnology&#65288;China&#65289;</td>
			<td style="width:207px;">01-023</td>
			<td style="width:197px;"></td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;">Filter paper</td>
			<td style="width:177px;">GE Healthcare brand(Sweden)&#160;&#160;</td>
			<td>10311387</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">50-mL tube</td>
			<td style="width:177px;">CORNING(Amercia)</td>
			<td style="width:207px;">430290</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">Centrifuge</td>
			<td style="width:177px;">Eppendorf(Amercia)</td>
			<td style="width:207px;">5804R</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;">Tween-20</td>
			<td style="width:177px;">Coolaber&#65288;China&#65289;</td>
			<td style="width:207px;">CT11551-100ml</td>
			<td></td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:216px;">Culture dish</td>
			<td style="width:177px;">Thermofisher(Amercia)</td>
			<td>150326</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">0.5-5 mL pipette</td>
			<td>Eppendorf</td>
			<td style="width:207px;">&#160;4920000105</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">100-1000uL pipette</td>
			<td>Eppendorf</td>
			<td>4920000083</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">Vacuum pump</td>
			<td style="width:177px;">Leybold</td>
			<td style="width:207px;">D25B</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">Dissection needle</td>
			<td style="width:177px;">FST</td>
			<td style="width:207px;">26000-35</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">Incubator</td>
			<td style="width:177px;">MEMMERT</td>
			<td style="width:207px;">PYX313</td>
			<td></td>
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		<tr height="25">
			<td height="25" style="height:25px;width:216px;">Inoculation ring</td>
			<td style="width:177px;">Greiner Bio One</td>
			<td style="width:207px;">731175</td>
			<td></td>
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the plant infection test: spray and wound-mediated inoculation with the plant pathogen magnaporthe grisea

Plants possess a powerful system to defend themselves against potential threats by pathogenic fungi. For agriculturally important plants, however, current measures to combat such pathogens have proved too conservative and, thus, not sufficiently effective, and they can potentially pose environmental risks. Therefore, it is extremely necessary to identify host-resistance factors to assist in controlling plant diseases naturally through the identification of resistant germplasm, the isolation and characterization of resistance genes, and the molecular breeding of resistant cultivars. In this regard, there is need to establish an accurate, rapid, and large-scale inoculation method to breed and develop plant resistance genes. The rice blast fungal pathogen Magnaporthe grisea causes severe disease symptoms and yield losses. Recently, M. grisea has emerged as a model organism for studying the mechanisms of plant-fungal pathogen interactions. Hence, we report the development of a plant virulence test method that is specific for M. grisea. This method provides for both spray inoculation with a conidial suspension and wounding inoculation with mycelium cubes or droplets of conidial suspension. The key step of the wounding inoculation method for detached rice leaves is to make wounds on plant leaves, which avoids any interference caused by host penetration resistance. This spray/wounding protocol contributes to the rapid, accurate, and large-scale screening of the pathotypes of M. grisea isolates. This integrated and systematic plant infection method will serve as an excellent starting point for gaining a broad perspective of issues in plant pathology.

The entire workflow for the technique is shown in Figure 1. The plant infection assays were performed on 14-day-old susceptible rice seedlings (O. sativa cv CO-39) or susceptible 7-day-old barley leaves (H. vulgare cv Golden Promise)7,8,9. To test for an infection on the rice leaves, a conidial suspension (1.0 x 105 spores/mL) of the ...

Watch this Scientific Journal Video about The Plant Infection Test: Spray and Wound-Mediated Inoculation with the Plant Pathogen Magnaporthe Grisea at JoVE.com

The Plant Infection Test: Spray and Wound-Mediated Inoculation with the Plant Pathogen Magnaporthe Grisea

Here, we present a protocol to test plant virulence with the plant pathogen Magnaporthe grisea. This report will contribute to the large-scale screening of the pathotypes of fungi isolates and serve as an excellent starting point for understanding the resistant mechanisms of plants during molecular breeding.

The Plant Infection Test: Spray and Wound-Mediated Inoculation with the Plant Pathogen Magnaporthe Grisea

Plants possess a powerful system to defend themselves against potential threats by pathogenic fungi. For agriculturally important plants, however, current ...

This video can help instruct key methods in the plant infection field such as free and wanted mediated inoculation with the plant pathogen Magnaporthe grisea. The main advantage of this technique is that the spraying, wounding protocol contributes to the rapid, accurate, and large scale screening of the pathotypes of fungi isolates. The implications of this technique relates to the study of physiology to combat plant pathogens because it is very important for the prevention and control of large scale plant diseases.This method can provide insight into conservation pathogeny mechanism in fungi. It can also be applied to the main variety of agriculture plants such as rice or barley. Generally individuals new to this method will struggle because it is difficult to scrape conidia gently with the sterile cotton swabs.The demonstration of this method is critical as a collection of scrape wounds without penetrating the leaves as the main means of detached rice or barley leaves is difficult. To begin weigh out 30 to 50 grams of oatmeal. Add the oatmeal to 800 milliliters of distilled deionized water and boil the mixture for 30 minutes in an electric pot.Next filter the boiled oatmeal mixture through a piece of gauze into a beaker. Then add 150 milliliters of tomato juice and 20 grams of agar to the beaker. Add distilled deionized water to the beaker up to 1000 milliliters.Soak about 50 rice seeds in distilled deionized water for 3 days then wrap the seeds in moistened gauze and germinate them on moist filter paper in Petri dishes. Next plant the seedlings in pots with autoclaved potting soil. After watering the seedlings cover them with a layer of vermiculite.Place the seedlings in a glass house maintained at 25 degrees Celsius for one to two weeks. Next use sterile surgical scissors to cut three layers of filter paper into eight centimeter circles. Place the filter paper circles onto 100 millimeter sterile plastic plates.Add just enough distilled deionized water to each dish to soak the filter paper. Then place two sterile tooth picks two to three centimeters apart in each culture dish. Two weeks after sowing collect the leaves of the rice plants by cutting the lower part of the stem.Using a thermostatic incubator culture the M.grisea strains on OTA plates at 25 degrees Celsius for four days. Then use a pipette to add two milliliters of distilled deionized water to each plate. Using an inoculation loop scrape the mycelia from the wild type and mutant strains into the mycelia debris.Collect the mycelia debris and transfer it to a new OTA plate. Then dry the mycelia debris in a clean bench. Add two milliliters of distilled deionized water to the cultured mycelium dish and use a sterile cotton swab to gently scrape the conidia.Filter the conidia suspension through two layers of lens paper and transfer the suspension to a new 50 millimeter tube. Then centrifuge the tube for five minutes at 5000 times g. After centrifugation remove the supernatant and re-suspend the pellet with Tween-20 solution resulting in a concentration of 20 000 conidia per milliliter.Pour the suspension into a hand-held sprayer then spray approximately 10 milliliters of the conidial suspension onto the leaves from the two week old rice plants. Spray the leaves of the control plants with the Tween-20 solution. After this incubate the leaves in a dark humid box for 24 hours.Next transfer the leaves to a moist chamber with fluorescent light for 12 hours. Using an anatomical needle scrape three two-to-three-centimeter long wounds in the main veins of detached rice leaves. Place the scraped leaves on toothpicks and spray them with Tween-20 solution.Next cut a half-by-half-centimeter mycelial plug from the OTA plates containing each M.grisea strain. Place the plugs on the wounded leaves and incubate them in a humid chamber at 25 degrees Celsius for three to eight days. After the incubation period examine and evaluate the lesions according to the scoring system provided by the International Rice Research Institute.Finally photograph the diseased leaves to evaluate the infectiousness of the tested strains. In this protocol plant infection assays using M.grisea strains P131 and Com1 were performed on susceptible rice seedlings. The P131 inoculated wild type leaves displayed the typical robust lesions of rice blast.However the Com1 inoculated leaves showed obvious infection defects and did not elicit a full infection. To determine if M.grisea could infect host cells through wounds abraded leaves of wild type plants were inoculated with mycelial plugs or conidial droplets. The spray inoculated leaves showed no infection defects.In contrast the leaves inoculated via mycelial plugs displayed obvious defects. While attempting this procedure it is important to scrape three two-to-three-centimeter long wounds in the main veins of the detached rice leaves. Following this procedure other methods like pathogen inoculation can be performed in order to identify and analyze crop disease resistance.After its development this technique paves the way for researchers in the field of plant pathogens to explore rice blast disease in modern organisms. Don't forget that working with Magnaporthe grisea can be hazardous and precautions such as wearing gloves should always be taken when performing these procedures.

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Environment

Methods for Performing Crosses in Setaria viridis, a New Model System for the Grasses

Setaria viridis is an emerging model system for C4 grasses. It is closely related to the bioenergy feed stock switchgrass and the grain crop foxtail millet. Recently, the 510 Mb genome of foxtail millet, S. italica, has been sequenced 1,2 and a 25x coverage genome sequence of the weedy relative S. viridis is in progress. S. viridis has a number of characteristics that make it a potentially excellent model genetic system including a rapid generation time, small stature, simple growth requirements, prolific seed production 3 and developed systems for both transient and stable transformation 4. However, the genetics of S. viridis is largely unexplored, in part, due to the lack of detailed methods for performing crosses. To date, no standard protocol has been adopted that will permit rapid production of seeds from controlled crosses.
The protocol presented here is optimized for performing genetic crosses in S. viridis, accession A10.1. We have employed a simple heat treatment with warm water for emasculation after pruning the panicle to retain 20-30 florets and labeling of flowers to eliminate seeds resulting from newly developed flowers after emasculation. After testing a series of heat treatments at permissive temperatures and varying the duration of dipping, we have established an optimum temperature and time range of 48 &deg;C for 3-6 min. By using this method, a minimum of 15 crosses can be performed by a single worker per day and an average of 3-5 outcross progeny per panicle can be recovered. Therefore, an average of 45-75 outcross progeny can be produced by one person in a single day. Broad implementation of this technique will facilitate the development of recombinant inbred line populations of S. viridis X S. viridis or S. viridis X S. italica, mapping mutations through bulk segregant analysis and creating higher order mutants for genetic analysis.

Methods for Performing Crosses in Setaria viridis, a New Model System for the Grasses

We have developed a methodology for performing crosses in Setaria viridis (S. viridis). The method involves pruning the panicle prior to a hot water treatment to kill viable pollen. Crosses are performed following a well-controlled growth regime and typically result in the recovery of 1 to 7 cross-pollinated seed/s per panicle.

Setaria viridis is an emerging model system for C4 grasses. It is closely related to the bioenergy feed stock switchgrass and the grain crop foxtail ...

A Rapid and Efficient Method for Assessing Pathogenicity of Ustilago maydis on Maize and Teosinte Lines

Maize is a major cereal crop worldwide. However, susceptibility to biotrophic pathogens is the primary constraint to increasing productivity. U. maydis is a biotrophic fungal pathogen and the causal agent of corn smut on maize. This disease is responsible for significant yield losses of approximately $1.0 billion annually in the U.S.1 Several methods including crop rotation, fungicide application and seed treatments are currently used to control corn smut2. However, host resistance is the only practical method for managing corn smut. Identification of crop plants including maize, wheat, and rice that are resistant to various biotrophic pathogens has significantly decreased yield losses annually3-5. Therefore, the use of a pathogen inoculation method that efficiently and reproducibly delivers the pathogen in between the plant leaves, would facilitate the rapid identification of maize lines that are resistant to U. maydis. As, a first step toward indentifying maize lines that are resistant to U. maydis, a needle injection inoculation method and a resistance reaction screening method was utilized to inoculate maize, teosinte, and maize x teosinte introgression lines with a U. maydis strain and to select resistant plants.
Maize, teosinte and maize x teosinte introgression lines, consisting of about 700 plants, were planted, inoculated with a strain of U. maydis, and screened for resistance. The inoculation and screening methods successfully identified three teosinte lines resistant to U. maydis. Here a detailed needle injection inoculation and resistance reaction screening protocol for maize, teosinte, and maize x teosinte introgression lines is presented. This study demonstrates that needle injection inoculation is an invaluable tool in agriculture that can efficiently deliver U. maydis in between the plant leaves and has provided plant lines that are resistant to U. maydis that can now be combined and tested in breeding programs for improved disease resistance.

A Rapid and Efficient Method for Assessing Pathogenicity of Ustilago maydis on Maize and Teosinte Lines

The use of a needle injection method to inoculate maize and teosinte plants with the biotrophic pathogen Ustilago maydis is described. The needle injection inoculation method facilitates the controlled delivery of the fungal pathogen in between the plant leaves where the pathogen enters the plant through the formation of appresoria. This method is highly efficient, enabling reproducible inoculations with U. maydis.

Maize is a major cereal crop worldwide. However, susceptibility to biotrophic pathogens is the primary constraint to increasing productivity. U. maydis is ...

Single-plant, Sterile Microcosms for Nodulation and Growth of the Legume Plant Medicago truncatula with the Rhizobial Symbiont Sinorhizobium meliloti

Rhizobial bacteria form symbiotic, nitrogen-fixing nodules on the roots of compatible host legume plants. One of the most well-developed model systems for studying these interactions is the plant Medicago truncatula cv. Jemalong A17 and the rhizobial bacterium Sinorhizobium meliloti 1021. Repeated imaging of plant roots and scoring of symbiotic phenotypes requires methods that are non-destructive to either plants or bacteria. The symbiotic phenotypes of some plant and bacterial mutants become apparent after relatively short periods of growth, and do not require long-term observation of the host/symbiont interaction. However, subtle differences in symbiotic efficiency and nodule senescence phenotypes that are not apparent in the early stages of the nodulation process require relatively long growth periods before they can be scored. Several methods have been developed for long-term growth and observation of this host/symbiont pair. However, many of these methods require repeated watering, which increases the possibility of contamination by other microbes. Other methods require a relatively large space for growth of large numbers of plants. The method described here, symbiotic growth of M. truncatula/S. meliloti in sterile, single-plant microcosms, has several advantages. Plants in these microcosms have sufficient moisture and nutrients to ensure that watering is not required for up to 9 weeks, preventing cross-contamination during watering. This allows phenotypes to be quantified that might be missed in short-term growth systems, such as subtle delays in nodule development and early nodule senescence. Also, the roots and nodules in the microcosm are easily viewed through the plate lid, so up-rooting of the plants for observation is not required.

Single-plant, Sterile Microcosms for Nodulation and Growth of the Legume Plant Medicago truncatula with the Rhizobial Symbiont Sinorhizobium meliloti

Growth of Medicago truncatula plants in symbiosis with the nitrogen-fixing bacteria Sinorhizobium meliloti in individual, sterile microcosms made from standard laboratory plates permits frequent examination of root systems and nodules without compromising sterility. Plants can be maintained in these growth chambers for up to 9 weeks.

Rhizobial  bacteria form symbiotic, nitrogen-fixing nodules on the roots of compatible host  legume plants.  One  of the most well-developed model systems ...

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 ...

Application of Two-spotted Spider Mite Tetranychus urticae for Plant-pest Interaction Studies

The two-spotted spider mite, Tetranychus urticae, is a ubiquitous polyphagous arthropod herbivore that feeds on a remarkably broad array of species, with more than 150 of economic value. It is a major pest of greenhouse crops, especially in Solanaceae and Cucurbitaceae (e.g., tomatoes, eggplants, peppers, cucumbers, zucchini) and greenhouse ornamentals (e.g., roses, chrysanthemum, carnations), annual field crops (such as maize, cotton, soybean, and sugar beet), and in perennial cultures (alfalfa, strawberries, grapes, citruses, and plums)1,2. In addition to the extreme polyphagy that makes it an important agricultural pest, T. urticae has a tendency to develop resistance to a wide array of insecticides and acaricides that are used for its control3-7.
T. urticae is an excellent experimental organism, as it has a rapid life cycle (7 days at 27 &#176;C) and can be easily maintained at high density in the laboratory. Methods to assay gene expression (including in situ hybridization and antibody staining) and to inactivate expression of spider mite endogenous genes using RNA interference have been developed8-10. Recently, the whole genome sequence of T. urticae has been reported, creating an opportunity to develop this pest herbivore as a model organism with equivalent genomic resources that already exist in some of its host plants (Arabidopsis thaliana and the&#160;tomato Solanum lycopersicum)11. Together, these&#160;model organisms could provide insights into molecular bases of plant-pest interactions.
Here, an efficient method for quick and easy collection of a large number of adult female mites, their application on an experimental plant host, and the assessment of the plant damage due to spider mite feeding are described. The presented protocol enables fast and efficient collection of hundreds of individuals at any developmental stage (eggs, larvae, nymphs, adult males, and females) that can be used for subsequent experimental application.

Application of Two-spotted Spider Mite Tetranychus urticae for Plant-pest Interaction Studies

Protocols for efficient preparation of homogenous samples of spider mites, infestation of experimental plants, and assessment of plant damage, as required for studies of plant-pest interaction were developed.

The two-spotted spider mite, Tetranychus urticae, is a ubiquitous polyphagous arthropod herbivore that feeds on a remarkably broad array of species, with ...

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 ...

A New Application of the Electrical Penetration Graph (EPG) for Acquiring and Measuring Electrical Signals in Phloem Sieve Elements

Electrophysiological properties of cells are often studied in vitro, after dissociating them from their native environments. However, the study of electrical transmission between distant cells in an organism requires in vivo, artifact-free recordings of cells embedded within their native environment. The transmission of electrical signals from wounded to unwounded areas in a plant has since long piqued the interest of botanists. The phloem, the living part of the plant vasculature that is spread throughout the plant, has been postulated as a major tissue in electrical transmission in plants. The lack of suitable electrophysiological methods poses many challenges for the study of the electrical properties of the phloem cells in vivo. Here we present a novel approach for intracellular electrophysiology of sieve elements (SEs) that uses living aphids, or other phloem-feeding hemipteran insects, integrated in the electrical penetration graph (EPG) circuit. The versatility, robustness, and accuracy of this method made it possible to record and study in detail the wound-induced electrical signals in SEs of central veins of the model plant Arabidopsis thaliana1. Here we show that EPG-electrodes can be easily implemented for intracellular electrophysiological recordings of SEs in marginal veins, as well as to study the capacity of SEs to respond with electrical signals to several external stimuli. The EPG approach applied to intracellular electrophysiology of SEs can be implemented to a wide variety of plant species, in a large number of plant/insect combinations, and for many research aims.

A New Application of the Electrical Penetration Graph EPG for Acquiring and Measuring Electrical Signals in Phloem Sieve Elements

Electrical Penetration Graph (EPG) is a well-established technique for studying the feeding behavior of stylet-bearing insects. Here we show a new application of EPG as a non-invasive tool for the acquisition of intracellular electrophysiology recordings of sieve elements (SEs), the cells that form the phloem vasculature in plants.

Electrophysiological properties of cells are often studied in vitro, after dissociating them from their native environments. However, the study of ...

Operation of a 25 KWth Calcium Looping Pilot-plant with High Oxygen Concentrations in the Calciner

Calcium looping (CaL) is a post-combustion CO2 capture technology that is suitable for retrofitting existing power plants. The CaL process uses limestone as a cheap and readily available CO2 sorbent. While the technology has been widely studied, there are a few available options that could be applied to make it more economically viable. One of these is to increase the oxygen concentration in the calciner to reduce or eliminate the amount of recycled gas (CO2, H2O and impurities); therefore, decreasing or removing the energy necessary to heat the recycled gas stream. Moreover, there is a resulting increase in the energy input due to the change in the combustion intensity; this energy is used to enable the endothermic calcination reaction to occur in the absence of recycled flue gases. This paper presents the operation and first results of a CaL pilot plant with 100% oxygen combustion of natural gas in the calciner. The gas coming into the carbonator was a simulated flue gas from a coal-fired power plant or cement industry. Several limestone particle size distributions are also tested to further explore the effect of this parameter on the overall performance of this operating mode. The configuration of the reactor system, the operating procedures, and the results are described in detail in this paper. The reactor showed good hydrodynamic stability and stable CO2 capture, with capture efficiencies of up to 70% with a gas mixture simulating the flue gas of a coal-fired power plant.

Operation of a 25 KWth Calcium Looping Pilot-plant with High Oxygen Concentrations in the Calciner

This manuscript describes a procedure for operating a calcium looping pilot-plant for post-combustion carbon capture with high oxygen concentrations in the calciner in order to reduce or eliminate the flue gas recycle.

Calcium looping (CaL) is a post-combustion CO2 capture technology that is suitable for retrofitting existing power plants. The CaL process uses limestone ...

Adherence of Bacteria to Plant Surfaces Measured in the Laboratory

This manuscript describes a method to measure bacterial binding to axenic plant surfaces in the light microscope and through the use of viable cell counts. Plant materials used include roots, sprouts, leaves, and cut fruits. The methods described are inexpensive, easy, and suitable for small sample sizes. Binding is measured in the laboratory and a variety of incubation media and conditions can be used. The effect of inhibitors can be determined. Situations that promote and inhibit binding can also be assessed. In some cases it is possible to distinguish whether various conditions alter binding primarily due to their effects on the plant or on the bacteria.

An easy method for measuring and characterizing bacterial adhesion to plants, particularly roots and sprouts, is described in this article.

This manuscript describes a method to measure bacterial binding to axenic plant surfaces in the light microscope and through the use of viable cell ...

Specific and Accurate Detection of the Citrus Greening Pathogen Candidatus liberibacter spp. Using Conventional PCR on Citrus Leaf Tissue Samples

Citrus greening, also known as huanglongbing, is a destructive citrus disease ravaging citrus farms globally. This disease causes asymmetrical yellow leaf mottling, vein yellowing, defoliation, root decay, and ultimately, the death of the citrus plant. When infected, the citrus plants have stunted growth and produce flowers out of season. These flowers rarely yield fruit, and those that do yield small, bitter, irregularly shaped citrus fruit that are not desirable. This disease is spread by the Asian citrus psyllid, Diaphorina citri, and by the grafting of infected citrus tissue. The pathogen has a long and variable incubation period within the citrus plant&#8212;sometimes years, before symptoms appear. Attempts to culture this pathogen in vitro have been unsuccessful, possibly due to the low and uneven concentration of the pathogen within infected citrus tissue, or because it is difficult to replicate the environmental conditions conducive to growth of the pathogen. It is very difficult to identify the disease before it has spread, due to its long incubation period and researchers&#39; inability to culture the pathogen. As a result, the disease only becomes apparent after suddenly destroying a citrus farmer&#39;s entire yield. Presented here is a method for the accurate and specific detection of the citrus greening pathogen, Candidatus liberibacter spp. using a genomic DNA extraction kit and PCR. This method is simple, efficient, cost effective, and adaptable for quantitative analysis. This method can be adapted for use on any citrus tissue; however, it is potentially limited by the amount of pathogen present in the tissue. Nevertheless, this method will allow citrus farmers to identify infected citrus plants earlier, and curb the spread of this destructive disease before it can further spread.

Specific and Accurate Detection of the Citrus Greening Pathogen Candidatus liberibacter  spp. Using Conventional PCR on Citrus Leaf Tissue Samples

Citrus Greening is a particularly destructive disease affecting citrus crops globally. Presented here is a simple method using PCR and genomic DNA extraction of citrus leaf tissue for the accurate and precise identification of the citrus greening pathogen, Candidatus liberibacter spp.

Citrus greening, also known as huanglongbing, is a destructive citrus disease ravaging citrus farms globally. This disease causes asymmetrical yellow leaf ...