Name: generating homo- and heterografts between watermelon and bottle gourd for the study of cold-responsive micrornas
Uploaded: 2018-11-20T12:30:00
Description: Watch this Scientific Journal Video about Generating Homo- and Heterografts Between Watermelon and Bottle Gourd for the Study of Cold-responsive MicroRNAs at JoVE.com

This work was supported by the National Natural Science Foundation of China (31772291), the Research Project for Public Interest in Zhejiang Province (2017C32027), the Key Science Project of Plant Breeding in Zhejiang (2016C02051), and the National Program for the Support of Top-notch Young Professionals (to P.X.).

1. Seed Sterilization and Germination
<ol>
	<li>For surface sterilization, soak the bottle gourd seeds in a 500-mL beaker filled with water at 58 &#176;C with occasional stirring, until the water temperature drops to 40 &#176;C.</li>
	<li>Meanwhile, put 3 kg of peat soil into a nylon bag and, to sterilize it, autoclave it at 120 &#176;C/0.5 MPa for 20 min.</li>
	<li>Keep soaking the bottle gourd seeds for 4 - 5 h more with no stirring.
	<ol>
		<li>Once the water reaches room temperature, rinse the seeds 2x - 3x with di...

<ol>
	<li>Schwarz, D., Rouphael, Y., Colla, G., Venema, J. 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G., Hennig, L., K&#246;hler, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Grafting+as+a+research+tool.">Grafting as a research tool.</a> Plant Developmental Biology. , 11-26 (2010).</li><li>Li, 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=Grafting-responsive+miRNAs+in+cucumber+and+pumpkin+seedlings+identified+by+high-throughput+sequencing+at+whole+genome+level.">Grafting-responsive miRNAs in cucumber and pumpkin seedlings identified by high-throughput sequencing at whole genome level.</a> Physiologia Plantarum. 151 (4), 406-422 (2014).</li><li>Lakhotia, N., 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=Identification+and+characterization+of+miRNAome+in+root,+stem,+leaf+and+tuber+developmental+stages+of+potato+(Solanum+tuberosum+L.)+by+high-throughput+sequencing.">Identification and characterization of miRNAome in root, stem, leaf and tuber developmental stages of potato (Solanum tuberosum L.) by high-throughput sequencing.</a> BMC Plant Biology. 14 (1), 6 (2014).</li><li>Jones-Rhoades, M. W., Bartel, D. P., Bartel, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MicroRNAs+and+their+regulatory+roles+in+plants.">MicroRNAs and their regulatory roles in plants.</a> Annual Review of Plant Biology. 57, 19-53 (2006).</li><li>Puzey, J. R., Kramer, 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=Identification+of+conserved+Aquilegia+coerulea+microRNAs+and+their+targets.">Identification of conserved Aquilegia coerulea microRNAs and their targets.</a> Genetic. 448 (1), 46-56 (2009).</li><li>Matthewman, C. 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=miR395+is+a+general+component+of+the+sulfate+assimilation+regulatory+network+in+Arabidopsis.">miR395 is a general component of the sulfate assimilation regulatory network in Arabidopsis.</a> FEBS Letters. 586 (19), 3242-3248 (2012).</li><li>Ali, E. 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=Transmission+of+RNA+silencing+signal+through+grafting+confers+virus+resistance+from+transgenically+silenced+tobacco+rootstocks+to+non-transgenic+tomato+and+tobacco+scions.">Transmission of RNA silencing signal through grafting confers virus resistance from transgenically silenced tobacco rootstocks to non-transgenic tomato and tobacco scions.</a> Journal of Plant Biochemistry and Biotechnology. 25 (3), 245-252 (2016).</li><li>Li, Y. S., Li, C. H., Bai, L. Q., He, C. X., Yu, X. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MicroRNA+and+target+gene+responses+to+salt+stress+in+grafted+cucumber+seedlings.">MicroRNA and target gene responses to salt stress in grafted cucumber seedlings.</a> Acta Physiologiae Plantarum. 38 (2), 1-12 (2016).</li><li>Pagliarani, 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=The+accumulation+of+miRNAs+differentially+modulated+by+drought+stress+is+affected+by+grafting+in+grapevine.">The accumulation of miRNAs differentially modulated by drought stress is affected by grafting in grapevine.</a> Plant Physiology. 173 (4), 2180-2195 (2017).</li><li>Liu, N., Yang, J. H., Guo, S. G., Xu, Y., Zhang, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-wide+identification+and+comparative+analysis+of+conserved+and+novel+microRNAs+in+grafted+watermelon+by+high-throughput+sequencing.">Genome-wide identification and comparative analysis of conserved and novel microRNAs in grafted watermelon by high-throughput sequencing.</a> PLoS One. 8 (2), e57359 (2013).</li><li>Song, G. <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+2JC-350+automatic+grafting+machine+with+cut+grafting+method+for+vegetable+seedling.">Development of 2JC-350 automatic grafting machine with cut grafting method for vegetable seedling.</a> Transactions of the Chinese Society of Agricultural Engineering. 22 (12), 103-106 (2006).</li><li>Kumar, 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=Uncovering+leaf+rust+responsive+miRNAs+in+wheat+(triticum+aestivum+l.)+using+high-throughput+sequencing+and+prediction+of+their+targets+through+degradome+analysis.">Uncovering leaf rust responsive miRNAs in wheat (triticum aestivum l.) using high-throughput sequencing and prediction of their targets through degradome analysis.</a> Planta. 245 (1), 1-22 (2016).</li><li>Kohli, 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=Identification+and+characterization+of+wilt+and+salt+stress-responsive+microRNAs+in+chickpea+through+high-throughput+sequencing.">Identification and characterization of wilt and salt stress-responsive microRNAs in chickpea through high-throughput sequencing.</a> PLoS One. 9 (10), e108851 (2014).</li><li>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=Computational+challenges+in+next-generation+genomics.+International+Conference+on+Scientific+and+Statistical+Database+Management.">Computational challenges in next-generation genomics. International Conference on Scientific and Statistical Database Management.</a> ACM. 2, (2013).</li><li>Guo, S. 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=The+draft+genome+of+watermelon+(Citrullus+lanatus)+and+resequencing+of+20+diverse+accessions.">The draft genome of watermelon (Citrullus lanatus) and resequencing of 20 diverse accessions.</a> Nature Genetics. 45, 51-58 (2013).</li><li>Wang, 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=Gourdbase:+a+genome-centered+multi-omics+database+for+the+bottle+gourd+(lagenaria+siceraria),+an+economically+important+cucurbit+crop.">Gourdbase: a genome-centered multi-omics database for the bottle gourd (lagenaria siceraria), an economically important cucurbit crop.</a> Scientific Reports. 8 (1), 306 (2018).</li><li>Wang, X. F., Liu, X. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systematic+Curation+of+miRBase+Annotation+Using+Integrated+Small+RNA+High-Throughput+Sequencing+Data+for+C.+elegans+and+Drosophila.">Systematic Curation of miRBase Annotation Using Integrated Small RNA High-Throughput Sequencing Data for C. elegans and Drosophila.</a> Frontiers in Genetics. 2, 25 (2011).</li><li>Bo, X. C., Wang, S. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TargetFinder:+a+software+for+antisense+oligonucleotide+target+site+selection+based+on+MAST+and+secondary+structures+of+target+mRNA.">TargetFinder: a software for antisense oligonucleotide target site selection based on MAST and secondary structures of target mRNA.</a> Bioinformatics. 21 (8), 1401-1402 (2005).</li><li>. GOATOOLS: Tools for Gene Ontology Available from: <a target="_blank" href="https://doi.org/10.5281/zenodo.31628">https://doi.org/10.5281/zenodo.31628</a> (2015)</li><li>Wang, L. P., Li, G. J., Wu, X. H., Xu, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+proteomic+analyses+provide+novel+insights+into+the+effects+of+grafting+wound+and+hetero-grafting+per+se+on+bottle+gourd.">Comparative proteomic analyses provide novel insights into the effects of grafting wound and hetero-grafting per se on bottle gourd.</a> Scientia Horticulturae. 200 (8), 1-6 (2016).</li></ol>

In this protocol, we described in detail a highly efficient and reproducible method to make homo- and heterografts between watermelon and bottle gourd. This method, requiring no specific equipment, is very easy to operate and typically has a very high survival rate of grafting. The method can also be used to make grafts for other cucurbits, such as between watermelon, cucumber, and pumpkin.
It is worth noting that the relative size (age) of the rootstock and scion is critical to making a succe...

Grafting has long been employed as an agricultural technique to improve crop production and tolerance to biotic and abiotic stresses1,2,3. In heterografting systems, elite rootstocks can enhance water and nutrients uptake of plants, strengthen resistance to soil pathogens, and limit the negative effects of metal toxicity4,5, which may confer the grafts an enhanced growth vigor and increased tolerance to environmental stresses. In many cases, heterografting can also impact fruit qualities in horticultural plants, leading to improved fruit flavor and increased content of health-related compounds6,7. It has been found that the long-distance transfer of phytohormones, RNAs, peptides, and proteins between the rootstock and the scion is a fundamental mechanism modulating the growth and development reprogramming of scion plants8,9,10. Grafting has been widely used in studies of long-distance signaling and transport in relation to environmental adaptation11. Grafting experiments are especially powerful for unambiguous detection of transmitted molecules in receiving tissue or vascular sap, and activation or suppression of molecular targets due to signal transmission12.
Non-coding RNAs, a big class of RNA that exert important regulatory functions in cells, have been reported to play a role in facilitating plant adaptation to abiotic stress13. miRNAs are endogenous small non-coding RNAs of about 20 - 24 nt. Studies have revealed the regulatory role of miRNAs in various aspects of plant activities, such as shoot growth, lateral root formation14,15,16, nutrient uptake, sulfate metabolism and homeostasis17, and responses to biotic and abiotic stress18. Recently, the expression of miRNAs and their target genes were related to salt stress tolerance in heterografted cucumber seedlings19. In the intervariety grafts of grape, the responses of miRNA expression to drought stress were found to be genotype-dependent20.
The rapid development and decreasing cost of high-throughput sequencing technology have provided a great opportunity for the study of miRNA regulations in agronomical plants. Watermelon (Citrullus lanatus [Thunb.] Mansf.), an important cucurbit crop grown throughout the world, is susceptible to low temperatures. Bottle gourd (Lagenaria siceraria [Molina] Standl.) is a more climate-resilient cucurbit commonly used by farmers to graft with watermelon. The primary goal of the current study is to establish a standard, efficient, and convenient method for making heterografts between watermelon (Citrullus lanatus [Thunb.] Mansf.) and bottle gourd (Lagenaria siceraria [Molina] Standl). This protocol also provides a detailed experimental scheme and analytical procedures for the study of the regulation of miRNA expressions following grafting, which is useful for revealing the mechanisms underlying heterografting advantages.
The plant materials used in this study include the watermelon cultivar and the bottle gourd landrace. Watermelon cultivar is a commercial cultivar with high yield but susceptible to low temperatures. Bottle gourd landrace is a popular rootstock for grafting with watermelon, cucumber, and bottle gourd, due to its excellent tolerance of low temperatures21.

<table>
	<tbody>
		<tr>
			<td>TRIzol Reagent</td>
			<td>Invitrogen</td>
			<td>15596026</td>
			<td></td>
		</tr>
		<tr>
			<td>RNA-free DNase I</td>
			<td>Takara</td>
			<td>D2270A</td>
			<td></td>
		</tr>
		<tr>
			<td>Truseq Small RNA sample prep Kit</td>
			<td>Illumina</td>
			<td>RS-200-0012</td>
			<td></td>
		</tr>
		<tr>
			<td>2100 Bionalyser</td>
			<td>Agilent</td>
			<td>5067</td>
			<td></td>
		</tr>
		<tr>
			<td>DNA Polymerase</td>
			<td>Thermo Fisher Scientific</td>
			<td>F530S</td>
			<td></td>
		</tr>
		<tr>
			<td>UEA sRNA workbench 2.4-plant version&#160;(software)</td>
			<td>NA</td>
			<td>NA</td>
			<td>http://srna-workbench.cmp.uea.ac.uk/</td>
		</tr>
		<tr>
			<td>Rfam 11.0 database&#160;(website)</td>
			<td>NA</td>
			<td>NA</td>
			<td>http://rfam.janelia.org</td>
		</tr>
		<tr>
			<td>miRBase 22.0&#160;(website)</td>
			<td>NA</td>
			<td>NA</td>
			<td>http://www.mirbase.org/</td>
		</tr>
		<tr>
			<td>MIREAP(software)</td>
			<td>NA</td>
			<td>NA</td>
			<td>https://sourceforge.net/projects/mireap/</td>
		</tr>
		<tr>
			<td>TargetFinder&#160;(software)</td>
			<td>NA</td>
			<td>NA</td>
			<td>http://targetfinder.org/</td>
		</tr>
	</tbody>
</table>

generating homo- and heterografts between watermelon and bottle gourd for the study of cold-responsive micrornas

MicroRNAs (miRNAs) are endogenous small non-coding RNAs of about 20 - 24 nt, known to play important roles in plant development and adaptation. There is an accumulating evidence showing that the expressions of certain miRNAs are altered when grafting, an agricultural practice commonly used by farmers to improve crop tolerance to biotic and abiotic stresses. Bottle gourd is an inherently climate-resilient crop compared to many other major cucurbits, including watermelon, rendering it one of the most widely used rootstocks for the latter. The recent advancement of high-throughput sequencing technologies has provided great opportunities to investigate cold-responsive miRNAs and their contributions to heterograft advantages; yet, adequate experimental procedures are a prerequisite for this purpose. Here, we present a detailed protocol for efficiently generating homo- and heterografts between the cold-susceptible watermelon and the cold-tolerant bottle gourd, in addition to methods of tissue sampling, data generation, and data analysis. The presented methods are also useful for other plant-grafting systems, to interrogate miRNA regulations under various environmental stresses, such as heat, drought, and salinity.

<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/58242/58242fig2.jpg" /> 
Figure 2: Phenotypes of various grafts at room temperature and cold-stressed conditions. (a) This panel shows homo- and heterografted seedlings at room temperature as the control. (b) This panel shows homo- and heterografted seedlings after 48 h of cold treatment. <a href="https://www.jove.com/files/ftp_upload/58242/58242fig2large.jpg" target="_blank"...

Watch this Scientific Journal Video about Generating Homo- and Heterografts Between Watermelon and Bottle Gourd for the Study of Cold-responsive MicroRNAs at JoVE.com

Generating Homo- and Heterografts Between Watermelon and Bottle Gourd for the Study of Cold-responsive MicroRNAs

Here we present a detailed protocol for efficiently making homo- and heterografts between watermelon and bottle gourd, in addition to methods of tissue sampling, data generation, and data analysis, for the investigation of cold-responsive microRNAs.

MicroRNAs (miRNAs) are endogenous small non-coding RNAs of about 20 - 24 nt, known to play important roles in plant development and adaptation. There is ...

This method can help answer key questions in miRNA response to ability to stress in plant grafts such as how miRNA are regulated under cold stress in watermelon bottle gourd grafts. The main advantage of this technique is that it is highly efficient and reproducible method to make homo and heterografts. It requires no specific equipment, it is very easy to perform, and typically results in a very high survival rate of grafting.Through this method, can provide insight into miRNA response to cold stress in the watermelon bottle gourd graft system. It can also be applied to other modern organisms for revealing the mechanisms of local and long distance miRNA transportation. Visual demonstration of this method is critical as the grafting steps are difficult to learn.This step required advanced skills and are key to the survival of the grafted plants. To begin, soak bottle gourd seeds in a 500 milliliter beaker of 58 degrees Celsius water. Stir the seeds occasionally until the water temperature drops to 40 degrees Celsius.While the water cools, put three kilograms of peat soil into a nylon bag and autoclave it. Once the water reaches room temperature, rinse the seeds two to three times in distilled water and drain the excess water. Allow the seeds to sprout in a gauze bag at 28 degrees Celsius in the dark growth chamber.After germination, sow the seeds into plastic pots filled with the sterilized peat soil. When the bottle gourd seedlings develop two flattened cotyledons, repeat this process with watermelon seeds. Grow the bottle gourd and watermelon seedlings in a growth chamber.Add water to the seedlings once per day in the afternoon. Next, cut the hypocotyls of the watermelon seedlings two to three centimeters below the cotyledons. Cut the top of the bottle gourd seedlings at the side, immediately above the cotyledons.Then use a toothpick to make a hole in the top of the trimmed bottle gourd seedlings. Insert the trimmed watermelon seedlings into the hole to make heterografts. After this, prepare homografts using the previously described method.First, wrap the grafted seedlings in transparent polyethylene bags to maintain a relatively high humidity. Then maintain the wrapped seedlings in a growth chamber for seven days. After the seventh day, remove the bags and allow the plants to grow under the same conditions for seven to 10 days.Divide the seedlings into two groups, one for cold treatments and one for control. Return the control seedlings to the same environmental conditions. Place the cold treated seedlings into a growth chamber set to six degrees Celsius with the same light dark conditions as the control group.After 48 hours, leave the samples of the scion and rootstocks from the grafts. Freeze the samples immediately in liquid nitrogen and store them at minus 70 degrees Celsius. Transfer the frozen sample to a two milliliter microcentrifuge tube in liquid nitrogen.Add a stainless steel bead to each sample tube and homogenize the tissues to a fine powder. For each grafting combination, take equal amounts of ground sample from 10 seedlings and mix them in a 10 milliliter centrifuge tube. Add an appropriate amount of guanidium hydrochloride reagent.Next, add RNA-free DNase one to 150 units per milliliter at 37 degrees Celsius for one hour. Then determine the total RNA quantity on a microcapillary electrophoresis system. After this, thaw the library normalization reagents and adapters.Then ligate small RNase with the five prime and three prime adapters, and elute and purify them. Reverse transcribe the five prime and three prime ligated small RNase following the manufacturer's guidelines. Next, perform PCR amplification following the manufacturer's protocol.Then use the microcaillary electrophoresis system to ensure that the RNA integrity number is greater than seven. Load one microliter of an RNA library on the microcapillary electrophoresis system to ensure that the RNA integrity number is greater than seven. Finally, sequence the small RNA libraries on a high throughput sequencing instrument.Using this protocol, a 98%survival rate for grafting and the phenotypes for room temperature and cold stress conditions were obtained. sRNAs of 24 nucleotides made up the biggest class of sRNAs in all grafting combination, regardless of temperature treatment. After 48 hours of cold treatment, 30 and 268 microRNAs were up and down-regulated, respectively.In the leaves of the scion in heterografts, conversely, in the leaves of the rootstock, 31 and 12 microRNAs were up and down-regulated, respectively. In the watermelon-watermelon homografts, 64 and 83 microRNAs were up and down-regulated, respectively. This demonstrated that heterografting caused profound reprogramming of the microRNA expressions.While attempting this procedure, it's important to remember the relative size and age of the daughter stalk and the scion is critical to making a successful graft. Following this procedure, other methods like lncRNA sequencing, proteomic profiling can be performed in order to investigate the regulation of lncRNA and protein and the coding system in the grafting system. After its development, this technique paved the way for research in the field of plant abiotic tolerance to explore the mechanism of plant grafting advantage in Cucurbitaceae and beyond.Don't forget that working with guanidine hydrochloride can be extremely hazardous and appropriate precaution should always be taken with performing this procedure.

generating-homo-heterografts-between-watermelon-bottle-gourd-for

Research

JoVE Journal

Environment

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 ...

Empirical, Metagenomic, and Computational Techniques Illuminate the Mechanisms by which Fungicides Compromise Bee Health

Growers often use fungicide sprays during bloom to protect crops against disease, which exposes bees to fungicide residues. Although considered &#34;bee-safe,&#34; there is mounting evidence that fungicide residues in pollen are associated with bee declines (for both honey and bumble bee species). While the mechanisms remain relatively unknown, researchers have speculated that bee-microbe symbioses are involved. Microbes play a pivotal role in the preservation and/or processing of pollen, which serves as nutrition for larval bees. By altering the microbial community, it is likely that fungicides disrupt these microbe-mediated services, and thereby compromise bee health. This manuscript describes the protocols used to investigate the indirect mechanism(s) by which fungicides may be causing colony decline. Cage experiments exposing bees to fungicide-treated flowers have already provided the first evidence that fungicides cause profound colony losses in a native bumble bee (Bombus impatiens). Using field-relevant doses of fungicides, a series of experiments have been developed to provide a finer description of microbial community dynamics of fungicide-exposed pollen. Shifts in the structural composition of fungal and bacterial assemblages within the pollen microbiome are investigated by next-generation sequencing and metagenomic analysis. Experiments developed herein have been designed to provide a mechanistic understanding of how fungicides affect the microbiome of pollen-provisions. Ultimately, these findings should shed light on the indirect pathway through which fungicides may be causing colony declines.

Microbial consortia within bumble bee hives enrich and preserve pollen for bee larvae. Using next generation sequencing, along with laboratory and field-based experiments, this manuscript describes protocols used to test the hypothesis that fungicide residues alter the pollen microbiome, and colony demographics, ultimately leading to colony loss.

Growers often use fungicide sprays during bloom to protect crops against disease, which exposes bees to fungicide residues. Although considered ...

Protocol for Microplastics Sampling on the Sea Surface and Sample Analysis

Microplastic pollution in the marine environment is a scientific topic that has received increasing attention over the last decade. The majority of scientific publications address microplastic pollution of the sea surface. The protocol below describes the methodology for sampling, sample preparation, separation and chemical identification of microplastic particles. A manta net fixed on an &#187;A frame&#171; attached to the side of the vessel was used for sampling. Microplastic particles caught in the cod end of the net were separated from samples by visual identification and use of stereomicroscopes. Particles were analyzed for their size using an image analysis program and for their chemical structure using ATR-FTIR and micro FTIR spectroscopy. The described protocol is in line with recommendations for microplastics monitoring published by the Marine Strategy Framework Directive (MSFD) Technical Subgroup on Marine Litter. This written protocol with video guide will support the work of researchers that deal with microplastics monitoring all over the world.

The protocol below describes the methodology for: microplastics sampling on the sea surface, separation of microplastic and chemical identification of particles. This protocol is in line with the recommendations for microplastics monitoring published by the MSFD Technical Subgroup on Marine Litter.

Microplastic pollution in the marine environment is a scientific topic that has received increasing attention over the last decade. The majority of ...

Extraction of Organochlorine Pesticides from Plastic Pellets and Plastic Type Analysis

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment during manufacturing and transport. Because of their environmental persistence, they are widely distributed in the oceans and on beaches all over the world. They can act as a vector of potentially toxic organic compounds (e.g., polychlorinated biphenyls) and might consequently negatively affect marine organisms. Their possible impacts along the food chain are not yet well understood. In order to assess the hazards associated with the occurrence of plastic pellets in the marine environment, it is necessary to develop methodologies that allow for rapid determination of associated organic contaminant levels. The present protocol describes the different steps required for sampling resin pellets, analyzing adsorbed organochlorine pesticides (OCPs) and identifying the plastic type. The focus is on the extraction of OCPs from plastic pellets by means of a pressurized fluid extractor (PFE) and on the polymer chemical analysis applying Fourier Transform-InfraRed (FT-IR) spectroscopy. The developed methodology focuses on 11 OCPs and related compounds, including dichlorodiphenyltrichloroethane (DDT) and its two main metabolites, lindane and two production isomers, as well as the two biologically active isomers of technical endosulfan. This protocol constitutes a simple and rapid alternative to existing methodology for evaluating the concentration of organic contaminants adsorbed on plastic pieces.

Microplastics act as vector of potentially toxic organic contaminants with unpredictable effects. This protocol describes an alternative methodology for assessing the levels of organochlorine pesticides adsorbed on plastic pellets and identifying the polymer chemical structure. The focus is on pressurized fluid extraction and attenuated total reflectance Fourier transform infrared spectroscopy.

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment ...

Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron (Oxy)Hydroxides, Trace Elements, and Bacteria

Fate and speciation of trace elements (TEs), such as arsenic (As) and mercury (Hg), in aquifers are closely related to physio-chemical conditions, such as redox potential (Eh) and pH, but also to microbial activities that can play a direct or indirect role on speciation and/or mobility. Indeed, some bacteria can directly oxidize As(III) to As(V) or reduce As(V) to As(III). Likewise, bacteria are strongly involved in Hg cycling, either through its methylation, forming the neurotoxin monomethyl mercury, or through its reduction to elemental Hg&#176;. The fates of both As and Hg are also strongly linked to soil or aquifer composition; indeed, As and Hg can bind to organic compounds or (oxy)hydroxides, which will influence their mobility. In turn, bacterial activities such as iron (oxy)hydroxide reduction or organic matter mineralization can indirectly influence As and Hg sequestration. The presence of sulfate/sulfide can also strongly impact these particular elements through the formation of complexes such as thio-arsenates with As or metacinnabar with Hg.
Consequently, many important questions have been raised on the fate and speciation of As and Hg in the environment and how to limit their toxicity. However, due to their reactivity towards aquifer components, it is difficult to clearly dissociate the biogeochemical processes that occur and their different impacts on the fate of these TE.
To do so, we developed an original, experimental, column setup that mimics an aquifer with As- or Hg-iron-oxide rich areas versus iron depleted areas, enabling a better understanding of TE biogeochemistry in anoxic conditions. The following protocol gives step by step instructions for the column set-up either for As or Hg, as well as an example with As under iron and sulfate reducing conditions.

Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron OxyHydroxides, Trace Elements, and Bacteria

Fate and speciation of arsenic and mercury in aquifers are closely related to physio-chemical conditions and microbial activity. Here, we present an original experimental column setup that mimics an aquifer and enables a better understanding of trace element biogeochemistry in anoxic conditions. Two examples are presented, combining geochemical and microbiological approaches.

Fate and speciation of trace elements (TEs), such as arsenic (As) and mercury (Hg), in aquifers are closely related to physio-chemical conditions, such as ...

Ecosystem Fabrication (EcoFAB) Protocols for The Construction of Laboratory Ecosystems Designed to Study Plant-microbe Interactions

Beneficial plant-microbe interactions offer a sustainable biological solution with the potential to boost low-input food and bioenergy production. A better mechanistic understanding of these complex plant-microbe interactions will be crucial to improving plant production as well as performing basic ecological studies investigating plant-soil-microbe interactions. Here, a detailed description for ecosystem fabrication is presented, using widely available 3D printing technologies, to create controlled laboratory habitats (EcoFABs) for mechanistic studies of plant-microbe interactions within specific environmental conditions. Two sizes of EcoFABs are described that are suited for the investigation of microbial interactions with various plant species, including Arabidopsis thaliana, Brachypodium distachyon, and Panicum virgatum. These flow-through devices allow for controlled manipulation and sampling of root microbiomes, root chemistry as well as imaging of root morphology and microbial localization. This protocol includes the details for maintaining sterile conditions inside EcoFABs and mounting independent LED light systems onto EcoFABs. Detailed methods for addition of different forms of media, including soils, sand, and liquid growth media coupled to the characterization of these systems using imaging and metabolomics are described. Together, these systems enable dynamic and detailed investigation of plant and plant-microbial consortia including the manipulation of microbiome composition (including mutants), the monitoring of plant growth, root morphology, exudate composition, and microbial localization under controlled environmental conditions. We anticipate that these detailed protocols will serve as an important starting point for other researchers, ideally helping create standardized experimental systems for investigating plant-microbe interactions.

Ecosystem Fabrication EcoFAB Protocols for The Construction of Laboratory Ecosystems Designed to Study Plant-microbe Interactions

This article describes detailed protocols for ecosystem fabrication of devices (EcoFABs) that enable the studies of plants and plant-microbe interactions in highly controlled laboratory conditions.

Beneficial plant-microbe interactions offer a sustainable biological solution with the potential to boost low-input food and bioenergy production. A ...

Experimental Study of the Relationship Between Particle Size and Methane Sorption Capacity in Shale

The amount of adsorbed shale gas is a key parameter used in shale gas resource evaluation and target area selection, and it is also an important standard for evaluating the mining value of shale gas. Currently, studies on the correlation between particle size and methane adsorption are controversial. In this study, an isothermal adsorption apparatus, the gravimetric sorption analyzer, is used to test the adsorption capacity of different particle sizes in shale to determine the relationship between the particle size and the adsorption capacity of shale. Thegravimetric method requires fewer parameters and produces better results in terms of accuracy and consistency than methods like the volumetric method. Gravimetric measurements are performed in four steps: a blank measurement, preprocessing, a buoyancy measurement, and adsorption and desorption measurements. Gravimetric measurement is presently considered to be a more scientific and accurate method of measuring the amount of adsorption; however, it is time-consuming and requires a strict measuring technique. A Magnetic Suspension Balance (MSB) is the key to verify the accuracy and consistency of this method. Our results show that adsorption capacity and particle size are correlated, but not a linear correlation, and the adsorptions in particles sieved into 40 - 60 and 60 - 80 meshes tend to be larger. We propose that the maximum adsorption corresponding to the particle size is approximately 250 &#181;m (60 mesh) in the shale gas fracturing.

We use an isothermal adsorption apparatus, the gravimetric sorption analyzer, to test the adsorption capacity of different particle sizes of shale, in order to find out the relationship between particle size and the adsorption capacity of shale.

The amount of adsorbed shale gas is a key parameter used in shale gas resource evaluation and target area selection, and it is also an important standard ...

Harvesting Venom Toxins from Assassin Bugs and Other Heteropteran Insects

Heteropteran insects such as assassin bugs (Reduviidae) and giant water bugs (Belostomatidae) descended from a common predaceous and venomous ancestor, and the majority of extant heteropterans retain this trophic strategy. Some heteropterans have transitioned to feeding on vertebrate blood (such as the kissing bugs, Triatominae; and bed bugs, Cimicidae) while others have reverted to feeding on plants (most Pentatomomorpha). However, with the exception of saliva used by kissing bugs to facilitate blood-feeding, little is known about heteropteran venoms compared to the venoms of spiders, scorpions and snakes.
One obstacle to the characterization of heteropteran venom toxins is the structure and function of the venom/labial glands, which are both morphologically complex and perform multiple biological roles (defense, prey capture, and extra-oral digestion). In this article, we describe three methods we have successfully used to collect heteropteran venoms. First, we present electrostimulation as a convenient way to collect venom that is often lethal when injected into prey animals, and which obviates contamination by glandular tissue. Second, we show that gentle harassment of animals is sufficient to produce venom extrusion from the proboscis and/or venom spitting in some groups of heteropterans. Third, we describe methods to harvest venom toxins by dissection of anaesthetized animals to obtain the venom glands. This method is complementary to other methods, as it may allow harvesting of toxins from taxa in which electrostimulation and harassment are ineffective. These protocols will enable researchers to harvest toxins from heteropteran insects for structure-function characterization and possible applications in medicine and agriculture.

Although many insects in the suborder Heteroptera (Insecta: Hemiptera) are venomous, their venom composition and the functions of their venom toxins are mostly unknown. This protocol describes methods to harvest heteropteran venoms for further characterization, using electrostimulation, harassment, and gland dissection.

Heteropteran insects such as assassin bugs (Reduviidae) and giant water bugs (Belostomatidae) descended from a common predaceous and venomous ancestor, ...

Choice and No-Choice Bioassays to Study the Pupation Preference and Emergence Success of Ectropis grisescens

Many insects live above the ground as larvae and adults and as pupate below the ground. Compared to the above-ground stages of their life cycles, less attention has been paid on how environmental factors affect these insects when they pupate within the soil. The tea looper, Ectropis grisescens Warren (Lepidoptera: Geometridae), is a severe pest of tea plants and has caused huge economic losses in South China. The protocols described here aim to investigate, through multiple-choice bioassays, whether mature last-instar E. grisescens larvae can discriminate soil variables such as the substrate type and moisture content, and determine, through no-choice bioassays, the impact of the substrate type and moisture content on pupation behaviors and the emergence success of E. grisescens. The results would enhance the understanding of the pupation ecology of E. grisescens and may bring insights into soil-management tactics for suppressing E. grisescens populations. In addition, these bioassays can be modified to study the influences of various factors on the pupation behaviors and survivorship of soil-pupating pests.

Choice and No-Choice Bioassays to Study the Pupation Preference and Emergence Success of Ectropis grisescens

Here, we present a protocol to investigate the pupation preference of mature larvae of Ectropis grisescens in response to soil factors (e.g., substrate type and moisture content) using choice bioassays. We also present a protocol of no-choice bioassays to determine the factors that affect the pupation behaviors and survivorship of E. grisescens.

Many insects live above the ground as larvae and adults and as pupate below the ground. Compared to the above-ground stages of their life cycles, less ...

Long-term Video Tracking of Cohoused Aquatic Animals: A Case Study of the Daily Locomotor Activity of the Norway Lobster (Nephrops norvegicus)

We present a protocol related to a video-tracking technique based on the background subtraction and image thresholding that makes it possible to individually track cohoused animals. We tested the tracking routine with four cohoused Norway lobsters (Nephrops norvegicus) under light-darkness conditions for 5 days. The lobsters had been individually tagged. The experimental setup and the tracking techniques used are entirely based on the open source software. The comparison of the tracking output with a manual detection indicates that the lobsters were correctly detected 69% of the times. Among the correctly detected lobsters, their individual tags were correctly identified 89.5% of the times. Considering the frame rate used in the protocol and the movement rate of lobsters, the performance of the video tracking has a good quality, and the representative results support the validity of the protocol in producing valuable data for research needs (individual space occupancy or locomotor activity patterns). The protocol presented here can be easily customized and is, hence, transferable to other species where the individual tracking of specimens in a group can be valuable for answering research questions.

Long-term Video Tracking of Cohoused Aquatic Animals: A Case Study of the Daily Locomotor Activity of the Norway Lobster Nephrops norvegicus

Here we present a protocol to individually track animals over a long period of time. It uses computer vision methods to identify a set of manually constructed tags by using a group of lobsters as case study, simultaneously providing information on how to house, manipulate, and mark the lobsters.