We would like to thank Michelle Moon (Vanderbilt University) for assistance with photography. Vanderbilt University provided support to PA and SSLB is supported by DGE-1445197.

1. Plant Cultures
<ol>
	<li>Purchase seeds from any commercial vendor or collect from mature plants in the field. 
	NOTE: This protocol is suitable for most commercially available milkweed species (e.g., Asclepias incarnata, A. syriaca, A. curassavica, Gomphocarpus physocarpus). Some seeds may need to be cold-stratified, and instructions from the seed supplier should be checked.</li>
	<li>Plant seeds in a fine germinating soil (60&#8211;70% fine peat moss, perlite, vermi...

<ol>
	<li>Brisson, J. A., Stern, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+pea+aphid,+Acyrthosiphon+pisum.:+an+emerging+genomic+model+system+for+ecological,+developmental+and+evolutionary+studies.">The pea aphid, Acyrthosiphon pisum.: an emerging genomic model system for ecological, developmental and evolutionary studies.</a> BioEssays. 28, 747-755 (2006).</li><li>Dixon, A. F. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Aphid Ecology: An Optimization Approach. , (1985).</li><li>Consortium, T. I. A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome+Sequence+of+the+Pea+Aphid+Acyrthosiphon+pisum.">Genome Sequence of the Pea Aphid Acyrthosiphon pisum.</a> PLoS Biology. , 1000313 (2010).</li><li>Srinivasan, D. G., Brisson, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aphids:+A+Model+for+Polyphenism+and+Epigenetics.">Aphids: A Model for Polyphenism and Epigenetics.</a> Genetics Research International. 2012, 1-12 (2012).</li><li>Wenger, J. 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=Whole+genome+sequence+of+the+soybean+aphid,+Aphis+glycines.">Whole genome sequence of the soybean aphid, Aphis glycines.</a> Insect Biochememistry and Molecular Biology. , 1-10 (2017).</li><li>Li, Z. -. Q., 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=Ecological+adaption+analysis+of+the+cotton+aphid+(Aphis+gossypii)+in+different+phenotypes+by+transcriptome+comparison.">Ecological adaption analysis of the cotton aphid (Aphis gossypii) in different phenotypes by transcriptome comparison.</a> PLoS ONE. 8, 83180 (2013).</li><li>Wang, D., Liu, Q., Jones, H. D., Bruce, T., Xia, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+transcriptomic+analyses+revealed+divergences+of+two+agriculturally+important+aphid+species.">Comparative transcriptomic analyses revealed divergences of two agriculturally important aphid species.</a> BMC Genomics. 15 (1), 1023-1024 (2014).</li><li>Wu, 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=De+novo+characterization+of+the+pine+aphid+Cinara+pinitabulaeformis+Zhang+et+Zhang+transcriptome+and+analysis+of+genes+relevant+to+pesticides.">De novo characterization of the pine aphid Cinara pinitabulaeformis Zhang et Zhang transcriptome and analysis of genes relevant to pesticides.</a> PLoS ONE. 12, 0178496-0178517 (2017).</li><li>Birnbaum, S. S. L., Rinker, D. C., Gerardo, N. M., Abbot, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcriptional+profile+and+differential+fitness+in+a+specialist+milkweed+insect+across+host+plants+varying+in+toxicity.">Transcriptional profile and differential fitness in a specialist milkweed insect across host plants varying in toxicity.</a> Molecular Ecology. , (2017).</li><li>Dixon, A. F. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Insect Herbivore-Host Dynamics. , (2005).</li><li>Goggin, F. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plant-aphid+interactions:+molecular+and+ecological+perspectives.">Plant-aphid interactions: molecular and ecological perspectives.</a> Current Opinion in Plant Biology. 10, 399-408 (2007).</li><li>Will, T., Furch, A., Zimmermann, M. 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G., Rasmann, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toxic+cardenolides:+chemical+ecology+and+coevolution+of+specialized+plant-herbivore+interactions.">Toxic cardenolides: chemical ecology and coevolution of specialized plant-herbivore interactions.</a> New Phytologist. 194, 28-45 (2012).</li><li>Dobler, S., Petschenka, G., Pankoke, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coping+with+toxic+plant+compounds-+the+insect's+perspective+on+iridoid+glycosides+and+cardenolides.">Coping with toxic plant compounds- the insect's perspective on iridoid glycosides and cardenolides.</a> Phytochemistry. 72, 1593-1604 (2011).</li><li>Opitz, S. E. W., M&#252;ller, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plant+chemistry+and+insect+sequestration.">Plant chemistry and insect sequestration.</a> Chemoecology. 19, 117-154 (2009).</li><li>Birnbaum, S. S. L., Abbot, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insect+adaptations+toward+plant+toxins+in+milkweed-herbivores+systems+-+a+review.">Insect adaptations toward plant toxins in milkweed-herbivores systems - a review.</a> Entomologia Experimentalis et Applicata. 58, 579-610 (2018).</li><li>Rothschild, M., von Euw, J., Reichstein, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+glycosides+in+the+oleander+aphid,+Aphis+nerii.">Cardiac glycosides in the oleander aphid, Aphis nerii.</a> Journal of Insect Physiology. 16, 1141-1145 (1970).</li><li>Harrison, J. S., Mondor, E. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+for+an+invasive+aphid+'superclone':+extremely+low+genetic+diversity+in+oleander+aphid+(Aphis+nerii)+populations+in+the+southern+United+States.">Evidence for an invasive aphid 'superclone': extremely low genetic diversity in oleander aphid (Aphis nerii) populations in the southern United States.</a> PLoS ONE. 6, 17524 (2011).</li><li>Mooney, K. A., Halitschke, R., Kessler, A., Agrawal, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolutionary+trade-offs+in+plants+mediate+the+strength+of+trophic+cascades.">Evolutionary trade-offs in plants mediate the strength of trophic cascades.</a> Science. 327, 1642-1644 (2010).</li><li>Grabherr, M. 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=Full-length+transcriptome+assembly+from+RNA-Seq+data+without+a+reference+genome.">Full-length transcriptome assembly from RNA-Seq data without a reference genome.</a> Nature Biotechnology. 29, 644-652 (2011).</li><li>Haas, B. 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=De+novo+transcript+sequence+reconstruction+from+RNA-seq+using+the+Trinity+platform+for+reference+generation+and+analysis.">De novo transcript sequence reconstruction from RNA-seq using the Trinity platform for reference generation and analysis.</a> Nature Protocols. 8, 1494-1512 (2013).</li><li>Finn, R. D., 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+Pfam+protein+families+database:+towards+a+more+sustainable+future.">The Pfam protein families database: towards a more sustainable future.</a> Nucleic Acids Research. 44, 279-285 (2016).</li><li>The UniProt Consortium. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=UniProt:+the+universal+protein+knowledgebase.">UniProt: the universal protein knowledgebase.</a> Nucleic Acids Research. 45, 158-169 (2017).</li><li>Johnson, 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=NCBI+BLAST:+a+better+web+interface.">NCBI BLAST: a better web interface.</a> Nucleic Acids Research. 1 (36), 5-9 (2008).</li><li>Fu, L., Niu, B., Zhu, Z., Wu, S., Li, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CD-HIT:+accelerated+for+clustering+the+next+generation+sequencing+data.">CD-HIT: accelerated for clustering the next generation sequencing data.</a> Bioinformatics. 28 (23), 3150-3152 (2012).</li><li>Sim&#227;o, F. A., Waterhouse, R. M., Ioannidis, P., Kriventseva, E. V., Zdobnov, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BUSCO:+assessing+genome+assembly+and+annotation+completeness+with+single-copy+orthologs.">BUSCO: assessing genome assembly and annotation completeness with single-copy orthologs.</a> Bioinformatics. 31, 3210-3212 (2015).</li><li>Bolger, A. M., Lohse, M., Usadel, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trimmomatic:+a+flexible+trimmer+for+Illumina+sequence+data.">Trimmomatic: a flexible trimmer for Illumina sequence data.</a> Bioinformatics. 30, 2114-2120 (2014).</li><li>Langmead, B., Salzberg, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+gapped-read+alignment+with+Bowtie+2.">Fast gapped-read alignment with Bowtie 2.</a> Nature Methods. 9, 357-359 (2012).</li><li>Li, H., 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+Sequence+Alignment/Map+format+and+SAMtools.">The Sequence Alignment/Map format and SAMtools.</a> Bioinformatics. 25, 2078-2079 (2009).</li><li>Love, M. I., Huber, W., Anders, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moderated+estimation+of+fold+change+and+dispersion+for+RNA-seq+data+with+DESeq2.">Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2.</a> Genome Biology. 15, 31 (2014).</li><li>Rieu, I., Powers, S. J. <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+RT-PCR:+design,+calculations,+and+statistics.">Real-time quantitative RT-PCR: design, calculations, and statistics.</a> Plant Cell. 21, 1031-1033 (2009).</li><li>Malcolm, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+defence+in+chewing+and+sucking+insect+herbivores:+plant-derived+cardenolides+in+the+monarch+butterfly+and+oleander+aphid.">Chemical defence in chewing and sucking insect herbivores: plant-derived cardenolides in the monarch butterfly and oleander aphid.</a> Chemoecology. 1, 12-21 (1990).</li><li>Agrawal, A. A., Underwood, N., Stinchcombe, J. 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It has long been recognized that the aposematic A. nerii can provide insights into the patterns and mechanisms of resistance to plant defenses and particularly chemical sequestration18,37. A number of genomic resources have recently emerged for A. nerii10, offering new opportunities for ecological and functional genomic studies that use A. nerii as a model. We outline basic protocols in aphid and plant culture, a...

Aphids are small, hemimetabolous insects that colonize on diverse plant families worldwide. They are distinctive for several features, most notably their complex life cycles involving cyclical parthenogenesis and discrete polyphenisms, and their obligate nutritional symbioses with bacterial or yeast endosymbionts that supply nutrients missing from their diet of plant sap1. While most aphids are host plant specialists, some generalist species are important crop pests, inflicting considerable economic damage on crops either directly or via the pathogens and viruses they vector2. The publication of the first aphid genome in 2010, the pea aphid Acyrthosiphon pisum3, marked an important milestone in the study of aphid biology because it provided the genomic resources for addressing questions about the insect&#39;s adaptations to the herbivorous lifestyles, including those that might lead to a better control strategies4. Since that time, additional genomic resources have accumulated with the publication of an annotated genome for the soybean aphid Aphis glycines5, and publicly-available whole genome resources for another three-aphid species (Myzus cerasi (black cherry aphid), Myzus persicae (peach-potato aphid), Rhopalosiphum padi (bird cherry-oat aphid)6. Valuable de novo transcriptomic resources are available as well for a number of other aphid species (e.g.,Aphis gossypii (cotton aphid)7, Sitobion avenae (grain aphid)8, Cinara pinitabulaeformis (pine aphid)9, Aphis nerii (milkweed-oleander aphid)10).
Aphids have also made lasting contributions to our understanding of the plant-insect interactions and the ecology of the life on plants11. One area where aphids have made particularly important contributions is in our understanding of the chemical ecology of the host plant interactions. Herbivorous insects express diverse adaptations for overcoming plant defenses, and some even co-opt plant defenses for their own benefit12,13,14. For example, the milkweed-oleander aphid, Aphis nerii, is a bright yellow, invasive aphid found in temperate and tropical regions worldwide that colonizes on plants in the milkweed family (Apocynaceae). Plants in the family Apocynaceae have evolved diverse chemical defenses, including milky latex and cardiac glycosides known as cardenolides, that bind the cation carrier Na,K-ATPase and are effective deterrents to generalist herbivores15,16. Milkweed specialists express various modes of resistance to cardenolides, and some selectively or passively accumulate or modify cardenolides in their tissues as a means to deter predation or for other benefits17. A. nerii is thought to sequester cardenolides in this way, although the mechanisms and functional benefits remain unclear10,18.
Given the genomic resources at hand, A. nerii provides an excellent experimental model for the study of the molecular and genetic mechanisms involved in the chemo-ecological interactions between toxic host plants and their specialist herbivores. It is worth noting that, while some of the earliest studies of A. nerii focused on sequestration of cardenolides19, since that time, studies of A. nerii have provided insights into a broad set of evolutionary and ecological questions, including the genetic structure of invasive insects20 and the interplay between bottom-up and top-down regulation on the herbivore density21. A. nerii is thus a good candidate as an experimental model for an especially broad set of studies of the insect-plant interactions. Critical to the success of any study with A. nerii is the careful culture of aphid populations, which includes the culture of plants on which the aphids depend, as well as an efficient generation of high-quality -omic data. Our goal is to guide the reader through both. Outlined below are methods for the generation and maintenance of the plant and aphid cultures in the greenhouse and laboratory, DNA and RNA extractions, microsatellite analysis, de novo transcriptome assembly and annotation, transcriptome differential expression analysis, and qPCR verification of differentially expressed genes. While these methods are written for A. nerii, the general culturing, extraction, and analysis methods can extend to a variety of aphid species.

<table border="0" cellpadding="0" cellspacing="0" style="width:820px;" width="820">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="84">
			<td height="84" style="height:84px;width:64px;">Sun Gro Fafard Germination Mix</td>
			<td style="width:160px;">Hummert International</td>
			<td style="width:184px;">10-0952-2</td>
			<td style="width:412px;"></td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:64px;">Sun Gro Fafard 3B/ Metro Mix</td>
			<td>Hummert International</td>
			<td style="width:184px;">10-0951-2</td>
			<td></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:64px;">2x 4&#34; Round Standard Pot</td>
			<td>Anderson Pots</td>
			<td style="width:184px;">1503</td>
			<td></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:64px;">DreamTaq DNA Polymerase</td>
			<td>ThermoFisher Scientific</td>
			<td style="width:184px;">EP0701</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:64px;">Trizol</td>
			<td>ThermoFisher Scientific</td>
			<td style="width:184px;">15596026</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">SuperScript&#174; III First-Strand Synthesis kit</td>
			<td>ThermoFisher Scientific</td>
			<td style="width:184px;">18080051</td>
			<td></td>
		</tr>
		<tr height="126">
			<td height="126" style="height:126px;width:64px;">Power SYBR Green PCR Master Mix</td>
			<td>ThermoFisher Scientific</td>
			<td style="width:184px;">4367659</td>
			<td></td>
		</tr>
	</tbody>
</table>

maintaining biological cultures and measuring gene expression in aphis nerii: a non-model system for plant-insect interactions

Aphids are excellent experimental models for a variety of biological questions ranging from the evolution of symbioses and the development of polyphenisms to questions surrounding insect's interactions with their host plants. Genomic resources are available for several aphid species, and with advances in the next-generation sequencing, transcriptomic studies are being extended to non-model organisms that lack genomes. Furthermore, aphid cultures can be collected from the field and reared in the laboratory for the use in organismal and molecular experiments to bridge the gap between ecological and genetic studies. Last, many aphids can be maintained in the laboratory on their preferred host plants in perpetual, parthenogenic life cycles allowing for comparisons of asexually reproducing genotypes. Aphis nerii, the milkweed-oleander aphid, provides one such model to study insect interactions with toxic plants using both organismal and molecular experiments. Methods for the generation and maintenance of the plant and aphid cultures in the greenhouse and laboratory, DNA and RNA extractions, microsatellite analysis, de novo transcriptome assembly and annotation, transcriptome differential expression analysis, and qPCR verification of differentially expressed genes are outlined and discussed here.

Plant cultures: Seeds will take approximately two to four weeks, depending on the season, to grow large enough to be re-potted (Figure 1A). Re-potted seedlings will take another two to four weeks to grow to an optimal size for aphid cultures (Figure 1B).
Aphid cultures: Adult A. nerii are disti...

Watch this Scientific Journal Video about Maintaining Biological Cultures and Measuring Gene Expression in Aphis nerii: A Non-model System for Plant-insect Interactions at JoVE.com

Maintaining Biological Cultures and Measuring Gene Expression in Aphis nerii: A Non-model System for Plant-insect Interactions

The aphid Aphis nerii colonizes on highly-defended plants in the dogbane family (Apocyanaceae) and provides numerous opportunities to study plant-insect interactions. Here, we present a series of protocols for the maintenance of plant and aphid cultures, and the generation and analysis of molecular and -omic data for A. nerii.

Maintaining Biological Cultures and Measuring Gene Expression in Aphis nerii: A Non-model System for Plant-insect Interactions

Aphids are excellent experimental models for a variety of biological questions ranging from the evolution of symbioses and the development of polyphenisms ...

This method describes general steps for aphid culturing and steps for the genetic analysis of aphids. These methods can be applied to answer key questions in the evolution and ecology of aphids and the moleculare mechanisms underlying aphid biology. The main advantage of this technique is it can be generally applied to most aphid species and performed at a relatively low cost.Begin by filling a standard seedling tray with germination mix soil, taking care that the soil reaches the top of the wells. When all of the wells have been filled, make a three centimeter deep hole in the soil of each well and place one seed into each hole. Water the cells until the soil covering the seeds is saturated and place the tray in a green house with daily to every other day watering, to maintain a moderate soil moisture level.When the seedlings have grown their first set of full leaves fill four inch round pots with potting soil, up to about five centimeters below their rims. Create a whole in the soil deep enough to reach the bottom of the pot and gently scoop the mature seedlings by hand to place them deep within the holes in the new pots. Then, cover the seedlings with soil and water the seedlings daily to every other day to maintain a moderate soil moisture level.When the plants have grown at least three to four sets of full leaves and are at least ten centimeters tall, manually inspect the plants for any unwanted pests and use a mouth pipette to carefully transfer a single reproducing field collected adult aphid onto the leaf of the first plant to create an iso-clonal line. When all of the aphids have been transferred, securely cover the plants with a custom made cup cage, and place the aphid infested plants in a controlled environment chamber. To maintain the stock populations, use a mouth pipette to safely transfer one to three second or third instar nymphs, and one adult aged aphid, to a new plant on a weekly basis.And cover each plant with a new cup cage for culture as demonstrated. For DNA extraction from a single adult aphid, place the aphid near the bottom of a sterile 1.5 milliliter microcentrifuge tube containing liquid nitrogen and grind the aphid with a pestle. Next, add 100 microliters of lysis buffer to the microcentrifuge tube and continue to grind the crushed aphid until the sample is visibly disintegrated.Wash the pestle with an additional 100 microliters of lysis buffer, and incubate the ground aphid at 65 degrees Celsius for 30 minutes. At the end of the incubation add 14 microliters of aemulor potassium acetate to the tube and invert to mix. After 30 minutes on ice collect the cellular debris by centrifugation and transfer the supernatant to a new 1.5 milliliter microcentrifuge tube without disturbing the pellet.Add 200 microliters of cold 100 percent molecular grade ethanol to the supernatant and invert the tube to mix. After 15 minutes at room temperature, collect the precipitated DNA by centrifugation, and remove the ethanol by pipette. Resuspend the pellet in 200 microliters of cold 70 percent molecular grade ethanol with flicking for a second centrifuge wash.And resuspend the pellet in 200 microliters of fresh, cold 100 percent molecular grade ethanol. After the third centrifugation, place the tube horizontally on a piece of tissue paper for air drying for five to ten minutes. And resuspend the DNA pellet in 80 microliters of low tris edta.Then, quantify the resuspended DNA in a spectrophotometer, and store the remaining sample at four degrees Celsius. After crushing up to five adult aphids in liquid nitrogen as demonstrated, transfer the sample to a fume hood and add 800 microliters of guanidinium thiocyanate-phenol-chloroform extraction reagent to the sample tube. Homogenize the sample with a pestle and incubate the homogenate for five minutes at room temperature.Next, add 160 microliters of chloroform to the sample, followed by 15 seconds of vigorous shaking by hand. Then, incubate the sample for two to three minutes at room temperature and centrifuge to collect the extracted RNA. To precipitate the RNA, transfer the aqueous phase to new RNS free microcentrifuge tube without disturbing the intermediate phase, and add 400 microliters of isopropanol to the RNA.After a ten minute incubation at negative 20 degrees Celsius, collect the precipitated RNA by centrifugation. Then, wash the sample two times with one milliliter of 75 percent ethanol in diethyl pyrocarbonate treated water, to the sample with slow vortexing and centrifugation to remove any phenol contaminants. After the second wash, mostly air dry the pellet for five to ten minutes on a sterile bench, and dissolve the RNA pellet in 30 microliters of ultra pure water with gentle pipetting before a ten to 15 minute incubation at 55 to 60 degrees Celsius.Seeds will take approximately two to four weeks, depending on the season, to grow large enough to be repotted. Repotted seedlings will take another two to four weeks to grow to an optimal size for aphid culture. Adult aye-near-ee-eye are distinguished by a darkened cauda, and may be unwinged or winged.Developing wing pads become visible when nymphs reach the third instar. Single adult aye-near-ee-eye will yield approximately 100 to 200 nanograms per microliter of DNA and 150 to 300 nanograms per microliter of RNA. The relative expression of a candidate gene under different treatment conditions can then be calculated.When attempting this procedure it's important to not contaminate you're iso-clonal stocks. Also, remember that the quality of your aphids is highly dependent upon the quality of your plants. Following this procedure, other extractions and sequencing techniques can be performed to answer question about the molecular mechanisms underlying aphid biology.

maintaining-biological-cultures-measuring-gene-expression-aphis-nerii

Research

JoVE Journal

Genetics

7.5K 조회수.  Vanderbilt University. This method describes general steps for aphid culturing and steps for the genetic analysis of aphids. These methods can be applied to answer key questions in the evolution and ecology of aphids and the moleculare mechanisms underlying aphid biology. The main advantage of this technique is it can be generally applied to most aphid species and performed at a relatively low cost.Begin by filling a standard seedling tray with germination mix soil, taking care that the soil reaches the top ...