Name: detection of phytophthora capsici in irrigation water using loop-mediated isothermal amplification
Uploaded: 2020-06-25T13:00:00
Description: Watch this Scientific Journal Video about Detection of Phytophthora capsici in Irrigation Water using Loop-Mediated Isothermal Amplification at JoVE.com

This work received the financial support of Georgia Commodity Commission for Vegetables project ID# FP00016659. The authors thank Dr. Pingsheng Ji, University of Georgia and Dr. Anne Dorrance, Ohio State University for providing pure cultures of Phytophthora spp. We also thank Li Wang and Deloris Veney for their technical assistance throughout the study.

1. On-site detection of Phytophthora capsici from irrigation water using portable loop-mediated isothermal amplification
<ol>
	<li>Setting up the pump and filter
	<ol>
		<li>Attach a filtering flask to a tube that is connected to a hand pump so that when the pump is activated, air will be pulled in through the mouth of the filtering flask.</li>
		<li>Fit the Buchner funnel into the rubber stopper to the mouth of the filtering flask and fit the appropriately sized piece of filter paper into the Buchner funnel s...

<ol>
	<li>Hong, C., Moorman, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plant+pathogens+in+irrigation+water:+challenges+and+opportunities.">Plant pathogens in irrigation water: challenges and opportunities.</a> Critical Reviews in Plant Sciences. 24 (3), 189-208 (2005).</li><li>Malkawi, H. I., Mohammad, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiology,+Genetics,+Morphology,+&amp;+Microorganisms,+E.+o.+Survival+and+accumulation+of+microorganisms+in+soils+irrigated+with+secondary+treated+wastewater.">Physiology, Genetics, Morphology, &amp; Microorganisms, E. o. Survival and accumulation of microorganisms in soils irrigated with secondary treated wastewater.</a> Journal of Basic Microbiology. 43 (1), 47-55 (2003).</li><li>Bush, E. A., Hong, C., Stromberg, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluctuations+of+Phytophthora+and+Pythium+spp.+in+components+of+a+recycling+irrigation+system.">Fluctuations of Phytophthora and Pythium spp. in components of a recycling irrigation system.</a> Plant Disease. 87 (12), 1500-1506 (2003).</li><li>Ghimire, S. R., 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=Distribution+and+diversity+of+Phytophthora+species+in+nursery+irrigation+reservoir+adopting+water+recycling+system+during+winter+months.">Distribution and diversity of Phytophthora species in nursery irrigation reservoir adopting water recycling system during winter months.</a> Journal of Phytopathology. 159 (11-12), 713-719 (2011).</li><li>Hausbeck, M. K., Lamour, K. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phytophthora+capsici+on+vegetable+crops:+research+progress+and+management+challenges.">Phytophthora capsici on vegetable crops: research progress and management challenges.</a> Plant Disease. 88 (12), 1292-1303 (2004).</li><li>Gevens, A., Donahoo, R., Lamour, K., Hausbeck, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+Phytophthora+capsici+from+Michigan+surface+irrigation+water.">Characterization of Phytophthora capsici from Michigan surface irrigation water.</a> Phytopathology. 97 (4), 421-428 (2007).</li><li>Thomson, S., Allen, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Occurrence+of+Phytophthora+species+and+other+potential+plant+pathogens+in+recycled+irrigation+water.">Occurrence of Phytophthora species and other potential plant pathogens in recycled irrigation water.</a> Plant Disease Reporter. 58 (10), 945-949 (1974).</li><li>Lamour, K. H., Stam, R., Jupe, J., Huitema, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+oomycete+broad-host-range+pathogen+Phytophthora+capsici.">The oomycete broad-host-range pathogen Phytophthora capsici.</a> Journal of Molecular Plant Pathology. 13 (4), 329-337 (2012).</li><li>Sanogo, S., Ji, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Water+management+in+relation+to+control+of+Phytophthora+capsici+in+vegetable+crops.">Water management in relation to control of Phytophthora capsici in vegetable crops.</a> Agricultural Water Management. 129, 113-119 (2013).</li><li>Zhang, Z., Li, Y., Fan, H., Wang, Y., Zheng, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+detection+of+Phytophthora+capsici+in+infected+plant+tissues,+soil+and+water.">Molecular detection of Phytophthora capsici in infected plant tissues, soil and water.</a> Plant Pathology. 55 (6), 770-775 (2006).</li><li>Trout, C., Ristaino, J., Madritch, M., Wangsomboondee, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+detection+of+Phytophthora+infestans+in+late+blight-infected+potato+and+tomato+using+PCR.">Rapid detection of Phytophthora infestans in late blight-infected potato and tomato using PCR.</a> Plant Disease. 81 (9), 1042-1048 (1997).</li><li>Sankaran, S., Mishra, A., Ehsani, R., Davis, 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+review+of+advanced+techniques+for+detecting+plant+diseases.">A review of advanced techniques for detecting plant diseases.</a> Commputers and Electronics in Agriculture. 72 (1), 1-13 (2010).</li><li>Wang, Z., 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=Development+of+an+improved+isolation+approach+and+simple+sequence+repeat+markers+to+characterize+Phytophthora+capsici+populations+in+irrigation+ponds+in+southern+Georgia.">Development of an improved isolation approach and simple sequence repeat markers to characterize Phytophthora capsici populations in irrigation ponds in southern Georgia.</a> Applied and Environmental Microbiology. 75 (17), 5467-5473 (2009).</li><li>Ali-Shtayeh, M., MacDonald, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Occurrence+of+Phytophthora+species+in+irrigation+water+in+the+Nablus+area+(West+Bank+of+Jordan).">Occurrence of Phytophthora species in irrigation water in the Nablus area (West Bank of Jordan).</a> Phytopathologia Mediterranea. , 143-150 (1991).</li><li>Pringsh, P. <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+serological+and+culture+plate+methods+for+detecting+species+of+Phytophthora,+Pythium,+and+Rhizoctonia+in+ornamental+plants.">Comparison of serological and culture plate methods for detecting species of Phytophthora, Pythium, and Rhizoctonia in ornamental plants.</a> Plant Disease. 74 (9), 655 (1990).</li><li>Stewart-Wade, 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=Plant+pathogens+in+recycled+irrigation+water+in+commercial+plant+nurseries+and+greenhouses:+their+detection+and+management.">Plant pathogens in recycled irrigation water in commercial plant nurseries and greenhouses: their detection and management.</a> Irrigation Science. 29 (4), 267-297 (2011).</li><li>Aragaki, M., Uchida, J. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphological+distinctions+between+Phytophthora+capsici+and+P.+tropicalis+sp.+nov.">Morphological distinctions between Phytophthora capsici and P. tropicalis sp. nov.</a> Mycologia. 93 (1), 137-145 (2001).</li><li>Tomlinson, J., Boonham, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Potential+of+LAMP+for+detection+of+plant+pathogens.">Potential of LAMP for detection of plant pathogens.</a> CAB Reviews Perspectives in Agriculture Veterinary Science Nutrition and Natural Resources. 3 (066), 1-7 (2008).</li><li>Li, P., 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+PCR-based+assay+for+distinguishing+between+A1+and+A2+mating+types+of+Phytophthora+capsici.">A PCR-based assay for distinguishing between A1 and A2 mating types of Phytophthora capsici.</a> Journal of the American Society for Horticultural Science. 142 (4), 260-264 (2017).</li><li>Dong, Z., 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=Loop-mediated+isothermal+amplification+assay+for+sensitive+and+rapid+detection+of+Phytophthora+capsici.">Loop-mediated isothermal amplification assay for sensitive and rapid detection of Phytophthora capsici.</a> Canadian Journal of Plant Pathology. 37 (4), 485-494 (2015).</li><li>Khan, 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=Comparative+evaluation+of+the+LAMP+assay+and+PCR-based+assays+for+the+rapid+detection+of+Alternaria+solani.">Comparative evaluation of the LAMP assay and PCR-based assays for the rapid detection of Alternaria solani.</a> Frontiers in Microbiology. 9, 2089 (2018).</li><li>Sowmya, N., Thakur, M., Manonmani, H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+and+simple+DNA+extraction+method+for+the+detection+of+enterotoxigenic+Staphylococcus+aureus+directly+from+food+samples:+comparison+of+PCR+and+LAMP+methods.">Rapid and simple DNA extraction method for the detection of enterotoxigenic Staphylococcus aureus directly from food samples: comparison of PCR and LAMP methods.</a> Journal of Applied Microbiology. 113 (1), 106-113 (2012).</li><li>Waliullah, 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=Comparative+analysis+of+different+molecular+and+serological+methods+for+detection+of+Xylella+fastidiosa+in+blueberry.">Comparative analysis of different molecular and serological methods for detection of Xylella fastidiosa in blueberry.</a> PLOS ONE. 14 (9), 0221903 (2019).</li><li>B&#246;hm, 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=Real-time+quantitative+PCR:+DNA+determination+in+isolated+spores+of+the+mycorrhizal+fungus+Glomus+mosseae+and+monitoring+of+Phytophthora+infestans+and+Phytophthora+citricola+in+their+respective+host+plants.">Real-time quantitative PCR: DNA determination in isolated spores of the mycorrhizal fungus Glomus mosseae and monitoring of Phytophthora infestans and Phytophthora citricola in their respective host plants.</a> Journal of Phytopathology. 147, 409-416 (1999).</li><li>Klimczak, L., Prell, H. J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+characterization+of+mitochondrial+DNA+of+the+oomycetous+fungus+Phytophthora+infestans.">Isolation and characterization of mitochondrial DNA of the oomycetous fungus Phytophthora infestans.</a> Current Genetics. 8 (4), 323-326 (1984).</li><li>Ghimire, S. R., 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=Detection+of+Phytophthora+species+in+a+run-off+water+retention+basin+at+a+commercial+nursery+in+plant+hardiness+zones+7+b+of+Virginia+in+winter.">Detection of Phytophthora species in a run-off water retention basin at a commercial nursery in plant hardiness zones 7 b of Virginia in winter.</a> Phytopathology. 96 (6), (2006).</li><li>Feng, W., Hieno, A., Kusunoki, M., Suga, H., Kageyama, K. J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LAMP+detection+of+four+plant-pathogenic+oomycetes+and+its+application+in+lettuce+fields.">LAMP detection of four plant-pathogenic oomycetes and its application in lettuce fields.</a> Plant Disease. 103 (2), 298-307 (2019).</li><li>Aglietti, C., 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=Real-time+loop-mediated+isothermal+amplification:+an+early-warning+tool+for+quarantine+plant+pathogen+detection.">Real-time loop-mediated isothermal amplification: an early-warning tool for quarantine plant pathogen detection.</a> AMB Express. 9 (1), 50 (2019).</li><li>Almasi, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+colorimetric+loop-mediated+isothermal+amplification+assay+for+the+visual+detection+of+Fusarium+oxysporum+f.+sp.+melonis.">Development of a colorimetric loop-mediated isothermal amplification assay for the visual detection of Fusarium oxysporum f. sp. melonis.</a> Horticultural Plant Journal. 5 (3), 129-136 (2019).</li><li>Gill, 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=Pathogenic+Pythium+from+irrigation+ponds.">Pathogenic Pythium from irrigation ponds.</a> Plant Disease Reporter. 54 (12), 1077-1079 (1970).</li></ol>

The testing of irrigation water for phytopathogens is a crucial step for growers using irrigation ponds and recycled water27. Irrigation ponds provide a reservoir and breeding ground for a number of phytopathogens as excess irrigation water is directed from the field to the pond carrying with it any pathogens that may have been present16,27. The traditional method for detection of a plant pathogens in a large water source is to set a bait ...

Recycling water in farms and nurseries is becoming increasingly popular due to the increase in water costs and environmental concerns behind water usage. Many irrigation methods have been developed for growers to reduce the spread and occurrence of plant disease. Regardless of the source of the water (irrigation or precipitation), runoff is generated, and many vegetable and nursery growers have a pond to collect and recycle runoff1. This creates a reservoir for possible pathogen accumulation favoring the spread of pathogens when the recycled water is used to irrigate crops2,3,4. Oomycete plant pathogens particularly benefit from this practice as zoospores will accumulate in water and the primary dispersive spore is self-motile but requires surface water5,6,7. Phytophthora capsici is an oomycete pathogen that affects a significant number of solanaceous and cucurbit crops in different ways8. Often, the symptoms are damping-off of seedlings, root and crown rot; however, in crops such as cucumber, squash, melon, pumpkin, watermelon, eggplant and pepper, entire harvests may be lost due to fruit rot9. Although there are known methods of detecting this plant pathogen, most require an infection to have already taken place which is too late for any preventative fungicides to have a significant effect10.
The traditional method to test irrigation water for the detection and diagnosis of targeted microorganisms is an antiquated approach when speed and sensitivity are crucial to success and profitable crop production11,12. Plant tissue susceptible to the targeted pathogen (e.g., eggplant for P. capsici) is attached to a modified trap that is suspended in an irrigation pond for extended period before being removed and inspected for infection. Samples from the plant tissue are then plated on semi-selective media (PARPH) and incubated for culture growth, then morphological identification is performed using a compound microscope13. There are other similar detection methods for other plant pathogens using selective media and plating small amounts of contaminated water before sub-culturing14,15. These methods require anywhere from 2 to 6 weeks, several rounds of sub-culturing to isolate the organism, and experience on Phytophthora diagnostics to be able to recognize the key morphological characters of each species. These traditional methods do not work well for detection of irrigation water contaminated by P. capsici due to factors such as interference by other microorganisms that are also present in the water sources. Some fast-growing microorganisms like Pythium spp. and water-borne bacteria can overgrow on the plate making P. capsici undetectable16,17.
The purpose of this study was to develop a sensitive and specific molecular method that can be used in both field and laboratory settings to detect P. capsici zoospores in irrigation water. The protocol includes the development of a novel loop-mediated isothermal amplification (LAMP) primer set able to specifically amplify P. capsici, based on a 1121-base pair (bp) fragment of P. capsici18,19. A previously developed LAMP primer from Dong et al. (2015) was used in comparison to the assay that was developed for this study20.
The LAMP assay is a relatively new form of molecular detection that has been demonstrated to be more rapid, sensitive, and specific than conventional polymerase chain reaction (PCR)21. In general, conventional PCR assays cannot detect under 500 copies (1.25 pg/&#181;L); in contrast, previous studies have shown that the sensitivity of LAMP can be 10 to 1,000 times higher than conventional PCR and can easily detect even 1 fg/&#181;L of genomic DNA22,23. Additionally, the assay can be carried out rapidly (often in 30 min) and on-site (in the field) by using a portable heating block for amplification and a colorimetric dye that changes color for a positive sample (removing the need for electrophoresis). In this study, we compared the sensitivity of PCR and LAMP assays using a filter extraction method. The proposed detection method allows researchers and extension agents to easily detect the presence of P. capsici spores from different water sources in less than two hours. The assay is proven to be more sensitive than conventional PCR and was validated in situ by detecting the presence of the pathogen in the irrigation water used by a grower. This detection method will allow growers to estimate the presence and population density of the pathogen in various water sources that are being used for irrigation, preventing devastating outbreaks and economic losses.

<table>
	<tbody>
		<tr>
			<td>Agarose gel powder</td>
			<td>Thomas Scientific</td>
			<td>C997J85</td>
			<td></td>
		</tr>
		<tr>
			<td>Buchner funnel</td>
			<td>Southern Labware</td>
			<td>JBF003</td>
			<td></td>
		</tr>
		<tr>
			<td>Bullet Blender</td>
			<td>Next Advance</td>
			<td>BBX24</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge 5430</td>
			<td>Eppendorf</td>
			<td>22620509</td>
			<td></td>
		</tr>
		<tr>
			<td>Chloroform</td>
			<td>Fischer Scientific</td>
			<td>C298-500</td>
			<td></td>
		</tr>
		<tr>
			<td>CTAB solution</td>
			<td>Biosciences</td>
			<td>786-565</td>
			<td></td>
		</tr>
		<tr>
			<td>Dneasy Extraction Kit</td>
			<td>Qiagen</td>
			<td>69104</td>
			<td></td>
		</tr>
		<tr>
			<td>Filter Flask</td>
			<td>United</td>
			<td>FHFL1000</td>
			<td></td>
		</tr>
		<tr>
			<td>Filter Paper</td>
			<td>United Scientific Supplies</td>
			<td>FPR009</td>
			<td></td>
		</tr>
		<tr>
			<td>Gel Green 10000X</td>
			<td>Thomas Scientific</td>
			<td>B003B68 (1/EA)</td>
			<td></td>
		</tr>
		<tr>
			<td>Genie III</td>
			<td>OptiGene</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hand pump</td>
			<td>Thomas Scientific</td>
			<td>1163B06</td>
			<td></td>
		</tr>
		<tr>
			<td>Iso-amyl Alcohol</td>
			<td>Fischer Scientific</td>
			<td>BP1150-500</td>
			<td></td>
		</tr>
		<tr>
			<td>LAVA LAMP master mix</td>
			<td>Lucigen</td>
			<td>30086-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic bead DNA extraction</td>
			<td>Genesig</td>
			<td>genesigEASY-EK</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic Separator</td>
			<td>Genesig</td>
			<td>genesigEASY-MR</td>
			<td></td>
		</tr>
		<tr>
			<td>polyvinylpyrrolidone</td>
			<td>Sigma Aldrich</td>
			<td>PVP40-500G</td>
			<td></td>
		</tr>
		<tr>
			<td>Primers</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Prism Mini Centrifuge</td>
			<td>Labnet</td>
			<td>C1801</td>
			<td></td>
		</tr>
		<tr>
			<td>T100 Thermal Cycler</td>
			<td>Bio-Rad</td>
			<td>1861096</td>
			<td></td>
		</tr>
		<tr>
			<td>UV Gel Doc</td>
			<td>Analytik Jena</td>
			<td>849-00502-2</td>
			<td></td>
		</tr>
		<tr>
			<td>Warmstart Colorimetric Dye</td>
			<td>Lucigen</td>
			<td>E1800m</td>
			<td></td>
		</tr>
		<tr>
			<td>Wide Mini ReadySub-Cell GT Cell</td>
			<td>Bio-Rad</td>
			<td>1704489EDU</td>
			<td></td>
		</tr>
		<tr>
			<td>70% isopropanol</td>
			<td>Fischer Scientific</td>
			<td>A451-1</td>
			<td></td>
		</tr>
	</tbody>
</table>

detection of phytophthora capsici in irrigation water using loop-mediated isothermal amplification

Phytophthora capsici is a devastating oomycete pathogen that affects many important solanaceous and cucurbit crops causing significant economic losses in vegetable production annually. Phytophthora capsici is soil-borne and a persistent problem in vegetable fields due to its long-lived survival structures (oospores and chlamydospores) that resist weathering and degradation. The main method of dispersal is through the production of zoospores, which are single-celled, flagellated spores that can swim through thin films of water present on surfaces or in water-filled soil pores and can accumulate in puddles and ponds. Therefore, irrigation ponds can be a source of the pathogen and initial points of disease outbreaks. Detection of P. capsici in irrigation water is difficult using traditional culture-based methods because other microorganisms present in the environment, such as Pythium spp., usually overgrow P. capsici making it undetectable. To determine the presence of P. capsici spores in water sources (irrigation water, runoff, etc.), we developed a hand pump-based filter paper (8-10 &#181;m) method that captures the pathogen&#8217;s spores (zoospores) and is later used to amplify the pathogen&#8217;s DNA through a novel loop-mediated isothermal amplification (LAMP) assay designed for the specific amplification of P. capsici. This method can amplify and detect DNA from a concentration as low as 1.2 x 102 zoospores/mL, which is 40 times more sensitive than conventional PCR. No cross-amplification was obtained when testing closely related species. LAMP was also performed using a colorimetric LAMP master mix dye, displaying results that could be read with the naked eye for on-site rapid detection. This protocol could be adapted to other pathogens that reside, accumulate, or are dispersed via contaminated irrigation systems.

Optimization of LAMP method 
In this study, we detected the presence of Phytophthora capsici in irrigation water using a portable loop-mediated isothermal amplification (LAMP) assay. First, the proposed LAMP assay was optimized by testing different LAMP primer concentrations [F3, B3 (0.1&#8211;0.5 &#181;M each); LF, LB (0.5&#8211;1.0 &#181;M each) and FIP, BIP (0.8&#8211;2.4 &#181;M each)], durations (30&#8211;70 min), and temperatures (55&#8211;70 &#176;C). The final LAMP primer mix used i...

Watch this Scientific Journal Video about Detection of Phytophthora capsici in Irrigation Water using Loop-Mediated Isothermal Amplification at JoVE.com

Detection of Phytophthora capsici in Irrigation Water using Loop-Mediated Isothermal Amplification

We developed a method to detect Phytophthora capsici zoospores in water sources using a filter paper DNA extraction method coupled with a loop-mediated isothermal amplification (LAMP) assay that can be analyzed in the field or in the lab.

Detection of Phytophthora capsici in Irrigation Water using Loop-Mediated Isothermal Amplification

Phytophthora capsici is a devastating oomycete pathogen that affects many important solanaceous and cucurbit crops causing significant economic losses in ...

Research

JoVE Journal

Environment

Colorimetric Paper-based Detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from Large Volumes of Agricultural Water

Colorimetric Paper-based Detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from Large Volumes of Agricultural Water

This protocol describes rapid colorimetric detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from large volumes (10 L) of ...

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) ...

EPA Method 1615. Measurement of Enterovirus and Norovirus Occurrence in Water by Culture and RT-qPCR. I. Collection of Virus Samples

EPA Method 1615 was developed with a goal of providing a standard method for measuring enteroviruses and noroviruses in environmental and drinking waters. ...

A Small Volume Bioassay to Assess Bacterial/Phytoplankton Co-culture Using WATER-Pulse-Amplitude-Modulated (WATER-PAM) Fluorometry

A Small Volume Bioassay to Assess Bacterial/Phytoplankton Co-culture Using WATER-Pulse-Amplitude-Modulated WATER-PAM Fluorometry

Conventional methods for experimental manipulation of microalgae have employed large volumes of culture (20 ml to 5 L), so that the culture can be ...

EPA Method 1615. Measurement of Enterovirus and Norovirus Occurrence in Water by Culture and RT-qPCR. Part III. Virus Detection by RT-qPCR

EPA Method 1615 measures enteroviruses and noroviruses present in environmental and drinking waters. This method was developed with the goal of having a ...

A Duplex Digital PCR Assay for Simultaneous Quantification of the Enterococcus spp. and the Human Fecal-associated HF183 Marker in Waters

A Duplex Digital PCR Assay for Simultaneous Quantification of the Enterococcus spp. and the Human Fecal-associated HF183 Marker in Waters

This manuscript describes a duplex digital PCR assay (EntHF183 dPCR) for simultaneous quantification of Enterococcus spp. and the human fecal-associated ...

Screening for Endocrine Activity in Water Using Commercially-available In Vitro Transactivation Bioassays

Screening for Endocrine Activity in Water Using Commercially-available In Vitro Transactivation Bioassays

In vitro transactivation bioassays have shown promise as water quality monitoring tools, however their adoption and widespread application has been ...

A Simple Planting Technique for Re-establishing Trees Where Frequent Inundation Occurs

Many of the Everglades tree islands have lost elevation over the past century and most of their trees have died such that they are now covered with ...

Bioindication Testing of Stream Environment Suitability for Young Freshwater Pearl Mussels Using In Situ Exposure Methods

Bioindication Testing of Stream Environment Suitability for Young Freshwater Pearl Mussels Using In Situ Exposure Methods

Knowledge of habitat suitability for freshwater mussels is an important step in the conservation of this endangered species group. We describe a protocol ...

Optimized Procedure for Determining the Adsorption of Phosphonates onto Granular Ferric Hydroxide using a Miniaturized Phosphorus Determination Method

This paper introduces a procedure to investigate the adsorption of phosphonates onto iron-containing filter materials, particularly granular ferric ...