Name: purification of high molecular weight genomic dna from powdery mildew for long-read sequencing
Uploaded: 2017-03-31T13:00:00.000+00:00
Duration: 6 min 56 s
Description: Watch this Scientific Journal Video about Purification of High Molecular Weight Genomic DNA from Powdery Mildew for Long-Read Sequencing at JoVE.com

This protocol was developed in support of a Joint Genome Institute-Community Sequencing Project (#1657). The work was supported in part by the Philomathia Foundation, the National Science Foundation (#0929226) and the Energy Biosciences Institute to S. Somerville; and by Swiss National Science Foundation (#310030_163260) to B. Keller. We would like to thank our colleagues, M. Figureroa and M. Miller (University of Minnesota), R. Panstruga (RWTH Aachen University), C. Pedersen (University of Copenhagen), P. Spanu (Imperial College), J. Taneja (University of California Berkeley), M. Wildermuth (University of California Berkeley), R. Wise (Iowa State University) and S. Xiao (University of Maryland) for their generous advice and for volunteering their protocols as we developed the protocol described here.

1. Herstellung von Pilzmaterial <ol><li> Wachsende Echten Mehltaus <ol><li> Wachsen Pflanzen in Wachstumskammern mit den folgenden Bedingungen: 22 ° C Tagestemperatur, 20 ° C Nachttemperatur, 80% relative Luftfeuchtigkeit, 14 h Tag-Länge und eine Lichtintensität von 125 &amp; mgr; E / m 2 / s (bereitgestellt von Leuchtstofflampen ). </li><li> Infect Gurkenpflanzen (Cucumis sativa Sorte Bush Meister) mit Golovinomyces cichoracearum Stamm UCSC1 wie beschrieben 18, 29. </li></ol></li><li> Ernte Echten Mehltaus Konidien <ol><li> Ernte Konidien von infizierten Pflanzen auf 7 bis 10 Tage nach der Inokulation ein kleines Vakuum mit einem in-line-Filter (11 &amp; mgr; m), auf dem die Konidien akkumulieren. Leichten Druck, führen Sie die Vakuumdüse entlang der Oberfläche des Blattes der Konidien zu sammeln. HINWEIS: Die durchschnittliche Ausbeute von G. cichoracearum beträgt 20 mg von Konidien aus einem stark InFECTED Gurkenblatt von etwa 130 cm 2 Fläche. </li><li> Bürste um 150 mg der Konidien (ungefähr 375 &amp; mgr; l Volumen oder Konidien 7-8 infizierte Gurkenblätter) von dem Filter auf ein Blatt Papier sauber. Von hier aus übertragen Konidien in 2 ml-Kryoröhrchen mit zwei 5/32-Zoll-Durchmesser vorge gekühlt (in flüssigem Stickstoff) Stahl Mahlkugeln. Unmittelbar Rohre flüssigen Stickstoff zurück. Speicher Röhrchen bei -80 ° C. </li></ol></li><li> Brechen öffnen Konidien durch Kugelmahlen <ol><li> Flash Aluminiumplatten der Kugelmühle in flüssigem Stickstoff einzufrieren. Last Kryoröhrchen in Kugelmühlenständer. Kräftig schütteln die Kryoröhrchen mit Konidien und Stahlkugeln in der Kugelmühle für 30 s bei 30 Zyklen / s (bei Raumtemperatur). Unmittelbar Kryoröhrchen in flüssigem Stickstoff wieder einfrieren. HINWEIS: Am Anfang Zugriff auf eine Probe von Konidien durch Mikroskopie bei 100-facher Vergrößerung für die Effizienz der Zellwand Bruch während des Schleifens. Bei Bedarf mahlt für weitere 1 bis 2 Runden von 30 s für 30 Zyklen / s, but hält die Anzahl der Runden auf ein Minimum. Routine Beurteilung der konidiale Bruch durch Mikroskopie in diesem Stadium ist nicht erforderlich, wenn optimale Bedingungen festgelegt wurden. </li></ol></li></ol> 2. Genomic DNA Purification <ol><li> Konidien Lysis <ol><li> schnell arbeitet Auftauen Konidien zu vermeiden, die Stahlkugeln aus Kryovials mit einem Magneten entfernen. Hinzufügen 700 &amp; mgr; l 65 ° C Lysepuffer (Tabelle 1) und vortex von 5 bis 10 s , bis eine Aufschlämmung gebildet wird. </li><li> Hinzufügen von 300 &amp; mgr; l vorgewärmtes (65 ° C) 5% (v / v) Sarkosyl und sanft invertieren mischen (1 Invertierung pro 3 s) fünfmal. Die Röhrchen für 30 min bei 65 ° C; invertieren sanft 3-mal bei 10, 20 und 30 min. Unter Verwendung einer Breitbohrungspipettenspitze übertragen gesamte Lösung neues 2 ml-Mikrozentrifugenröhrchen. In allen nachfolgenden Schritten, Mischung durch schonendes, langsames Inversion und überträgt die DNA-haltige Lösungen mit weiter Bohrung Pipettenspitzen. </li></ol></li><li> DNA-Extraktion I <ol><li> 1 Volumen von ChlorForm: Isoamylalkohol (24: 1 v / v) zu der Lyselösung und sanft invertieren fünfmal zu mischen. Inkubieren für 10 min bei Raumtemperatur, auf halber Strecke fünfmal zu mischen und erneut am Ende der Inkubation vorsichtig invertieren. Zentrifuge bei Raumtemperatur für 15 min bei 14.000 x g. Breitbohrungspipettenspitze, überträgt sorgfältig die wässrige Schicht zu neuen 2 ml-Mikrozentrifugenröhrchen; einschließlich Material von der Oberfläche vermeiden. </li></ol></li><li> DNA-Niederschlag I <ol><li> 1 Volumenraumtemperatur 100% Isopropanol (etwa 750 ul) und Invertzucker sanft sechsmal zu mischen. Zentrifuge bei Raumtemperatur für 15 min bei 14.000 x g. Entfernen Sie vorsichtig den Überstand und entsorgen. </li><li> Hinzufügen 450 ul vorgekühlten (-20 ° C) 70% Ethanol. Zentrifuge 5 min bei Raumtemperatur bei 14000 x g. Entfernen Sie vorsichtig den Überstand und entsorgen. Zentrifuge bei 1000 × g für 3 s, entfernen Sie vorsichtig den Überstand mit feiner Pipettenspitze und entsorgen. Luft-Trocknen des Pellets für 15 min eint Raumtemperatur. Trocknen Sie nicht länger als 15 min. </li><li> Das Pellet in 300 ul TE (10 mM Tris-Cl, 1 mM Ethylendiamintetra-Essigsäure, pH 8,0). Inkubiere über Nacht bei 4 ° C. Flick vorsichtig jegliches Restmaterial zu suspendieren, die nicht in Lösung ging. </li></ol></li><li> Um RNA-Kontamination zu entfernen, mit 10 ul RNase A (10 mg / ml). vorsichtig umdrehen dreimal zu mischen. Zentrifuge bei 1000 × g für 3 s. Inkubieren bei 37 ° C für 2 h. </li><li> II DNA Extraction <ol><li> In 300 ul Phenol: Chloroform: Isoamylalkohol (25: 24: 1 v / v) und vorsichtig invertieren fünfmal zu mischen. Inkubiere 10 Minuten bei Raumtemperatur sanft am Ende der Inkubation bei der Halbzeit fünf Mal zu mischen und wieder umgekehrt wird. Zentrifuge 15 min bei Raumtemperatur bei 14000 x g. Unter Verwendung einer Breitbohrungspipettenspitze, den Überstand in neue 1,5 ml-Mikrozentrifugenröhrchen. </li></ol></li><li> DNA-Präzipitation II <ol><li> 0.01 Volumen 3 M Natriumacetat pH 5,2 (approximately 3 &amp; mgr; l), invertieren fünfmal sanft zu mischen. Hinzufügen 2,5 Volumen vorgekühlten (-20 ° C) 100% Ethanol (etwa 750 ul). vorsichtig umdrehen fünf Mal mischen. Inkubieren über Nacht bei -20 ° C </li><li> Zentrifuge 30 min bei 4 ° C bei 14000 x g. Entfernen Sie vorsichtig den Überstand und entsorgen. </li><li> Hinzufügen 450 ul vorgekühlten (-20 ° C) 70% Ethanol. Zentrifuge 5 min bei 4 ° C bei 14000 x g. Entfernen Sie vorsichtig den Überstand und entsorgen. Zentrifuge bei 1000 × g für 3 s. Entfernen Sie vorsichtig den Überstand mit feiner Pipettenspitze und entsorgen. </li><li> Luft-Trocknen des Pellets für 30-60 min bei Raumtemperatur. Resuspendieren des Pellets in 27,5 &amp; mgr; l TE. Inkubiere über Nacht bei 4 ° C. Flick vorsichtig jegliches Restmaterial zu suspendieren, die nicht in Lösung ging. </li><li> 2,5 ul Aliquot in 22,5 &amp; mgr; l TE (Endvolumen 25 ul) für Qualitätskontrolltests (siehe unten). Store-DNA-Proben bei 4 ° C bis zur Vorlage für die Sequenzierung. Für die langfristige Lagerung, Aufbewahrung von ProbenGefrier-Auftau-Zyklen bei -80 ° C und Scher minimieren zu verhindern. HINWEIS: Achten Sie bei bei diesem Schritt als hochmolekulare genomische DNA Pipettieren kann schwierig sein, richtig zu pipettieren, und es ist wichtig, um sicherzustellen, dass „QC Aliquot“ ist eine genaue Darstellung der genomischen DNA-Probe. </li></ol></li></ol> 3. Qualitätskontrolle <ol><li> Probe Reinheit <ol><li> Verwendung eines TE blank, beurteilen die Probe Reinheit der DNA durch Laden von 1 &amp; mgr; l Aliquot des QC auf einem kleinvolumigen Spektrophotometer. Nehmen Sie A260 / A280 und A260 / A230 Lesungen. Reine DNA wird ein A260 / A280-Verhältnis von etwa 1,8 und A260 / A230-Verhältnis zwischen 1,8 und 2,2 aufweist. </li></ol></li><li> Quantifizierung von genomischer DNA <ol><li> Führen Quantifizierung von QC Aliquot Kommerzielle doppelsträngige DNA Quantifizierungsassay-Kit nach den Anweisungen des Herstellers. </li></ol></li><li> DNA Quality Assessment I <ol><li> Last etwa 60 ng genomische DNA und eineDNA-Leiter auf einem 0,7% Agarosegel in 1X TAE (40 mM Tris, 20 mM Essigsäure und 1 mM EDTA, pH 8,0). Führen Gelvorrichtung bei 70 V für 40 bis 45 min bis genomische DNA-Banden sind ungefähr 2 cm von dem Bohrloch und Bandtrennung in dem Leiter ist offensichtlich. Diese Bedingungen müssen basierend auf den verfügbaren Gelelektrophorese Vorrichtung angepasst werden. </li></ol></li><li> DNA Quality Assessment II <ol><li> Last etwa 60 ng genomischer DNA und einen hochmolekulare DNA-Leiter (geeignet für Pulsfeld-Gel-Elektrophorese) auf einem 1% igen Agarosegel in 0,5 × TBE (44,5 mM Tris, 44,5 mM Borsäure, 1 mM EDTA, pH 8,3) und läuft in 0,5x TBE Laufpuffer unter Verwendung eines 5 - 80 kbp Wellenform Pulsfeld-Gel-Elektrophorese-Protokoll für 16 h. </li></ol></li><li> Beurteilung von Bakterien-, Pilz- und Pflanzen Kontaminanten <ol><li> Durchführen der Polymerase-Kettenreaktion (PCR) die entsprechenden internen transkribierten Abstandshalter (ITS) Regionen der ribosomalen Gene zu amplifizieren unter Verwendung der Primer und Amplifikationsbedingungen Listeed in Tabelle 2. Last 10 &amp; mgr; l der erhaltenen Reaktions auf einem Gel. HINWEIS: Eine Bande, die den echten Mehltau ITS-Region sollte mit dem Pilz-ITS-Primer amplifiziert werden. DNA aus diesem Amplicon und jeden erzeugten Amplikons mit den bakteriellen, pflanzlichen oder Primer sollte den Ursprung der Verunreinigung zu bestimmen, sequenziert werden. Nur Mehltau ITS-Sequenzen sollten in der Pilz-Amplikon zu finden. </li></ol></li></ol>

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The authors have nothing to disclose.

Um rein, hochmolekulare genomische DNA aus den obligaten biotrophe echten Mehltaupilzen zu erhalten, eine modifizierte Version des zuvor beschriebenen Verfahrens wurde 30 entwickelt. Die durchschnittliche Ausbeute dieses optimierten Protokoll 7 ug DNA pro 150 mg Konidien, eine Verdoppelung der Ausbeute bei einem früheren Protokoll erhalten. Auch erhöhte sich die durchschnittliche Größe von etwa 20 kbp auf über 48,5 kbp. Dieses Protokoll wurde in dem Gurken- G. cichoracearum System o...

<html> Echte Mehltaupilze sind eine Gruppe von obligater biotrophen pilzliche Pflanzenpathogene , dass, wenn sie zusammengenommen, ist die größte Ursache für Pflanzenkrankheiten weltweit 1. Es gibt über 900 beschriebene Arten von Mehltau, der taxonomisch in fünf Stämme innerhalb der Familie Erisyphaceae 2 zusammengefasst wurde. Sowohl auf ihre wirtschaftlichen Bedeutung und die intimen Beziehung, die sie mit ihren Wirten zu entwickeln haben, Mehltau Krankheiten für&gt; 100 Jahre sind der Gegenstand der Forschung. Bei Infektion, entlocken Echte Mehltau drastische Veränderungen in der Zellstruktur, den Stoffwechsel und Molekularbiologie ihrer Wirte, diese Erreger zu profitieren. Das Studium der Echten Mehltau ist jedoch besonders schwierig aufgrund ihres obligater Lebensstil, und das Wachstum des Pilzes in Reinkultur ist noch nicht 3 beschrieben wurde, 4, 5,&quot;Xref&quot;&gt; 6, 7, 8. Zuverlässige, stabile genetische Transformation von Echten Mehltau hat auch noch nicht erreicht worden, obwohl transiente Transformation 9 bei einigen Arten berichtet, 10. Die Sequenzierung und Montage von Echtem Mehltau Genome hat sich als schwierig erwiesen, aufgrund einer Reihe von Merkmalen des Genoms selbst. Mehltaus Genomen sind groß (120-180 MBP) relativ zu anderen Pilz-Genomen, und bestehen aus 60 bis 90% gleichmäßig verteilt repetitiven Elementen 11. Diese Elemente sind nicht-long terminal repeats, sowie uncategorized repetitive Elemente. Zwei formae speciales einer einzigen echten Mehltau - Arten, Blumeria graminis f. sp. hordei und f. sp. tritici (Bgh und Bgt, respectively) sowie die Traubenmehltau Erysiphe necator, haben Bienenn sequenziert und Entwurf Genomen für mehr andere wurde 12 abgeschlossen, 13, 14. Die sich wiederholenden Natur der Genome hat Montage erschwert und das fertige Bgh - Genom wurde in 6.989 supercontigs mit L50 von 2 Mb 12 montiert. Trotz des großen Genoms scheint der Echte Mehltau eine kleine Anzahl von Protein - kodierenden Genen zu haben, mit 5.845 und 6.540 Genen vorhergesagt in Bgh und Bgt ist. Die sequenzierten echte Mehltaue scheinen auch mindestens 99 Kern Gene zu fehlen , die in anderen Pilzen wesentlich sind, die mit der Abhängigkeit der Pilze auf ihrer Wirtspflanze für das Überleben 11, 12, 13, 14 im Einklang steht. Repetitive Sequenzen nahe Telomere, Centromere, ribosomale RNEin Gen - Arrays und Regionen in transponierbaren Elementen angereichert sind schlecht aus Kurz gelesen Sequenzierungsstrategien zusammengesetzt und sind oft unterrepräsentiert in Genomanordnungen 15. Solche Bereiche für viele der Lücken verantwortlich sein wird angenommen , dass in Genomsequenzen auftreten, und dies gilt auch für die echte Mehltaue mit ihren umfangreichen Erweiterung von repetitiven Elementen 16. Highly Kunststoff Genomregionen oft in einem solchen repetitiven Regionen 3 gefunden. Sie dienen als Gebiet von Chromosomenumlagerungen und oft codieren Gene unter starkem Selektionsdruck, wie beispielsweise die Gene, die für Proteine ​​Effektor und die Gene Enzyme des Sekundärstoffwechsels kodieren. Die Fortschritte in der Einzelmolekül - Lang lesen Sequenzierungstechnologien bieten eine mögliche Lösung für die Sequenzierung durch sich wiederholende Regionen von Genomen 15. Zum Beispiel Faino et al. (2015) fanden heraus, dass auch lange Sequenz gelesen Technologien und m optischenapping ließ sie für zwei Stämme der pilzliche Pflanzenpathogen Verticillium Dahlia eine lückenlose Genomsequenz erzeugen, den Anteil der sich wiederholenden DNA - Sequenzen in das Genom zu verdreifachen, die Anzahl der Gen Annotationen erhöht (und die Verringerung der Anzahl von Teil oder fehlende Gen Annotationen ) und aufschlussreich Genom - Rearrangements 17. Um diese langfris las Sequenzierungstechnologien, hohe Konzentrationen von hohen Qualität genomischer DNA, mit minimalen Größen&gt; 20 kbp zu verwenden, benötigt. Hier beschreiben wir unsere Methoden zur konidiale Sammlung, Reinigung von hochmolekularer DNA von Konidien und unsere Qualitätskontrolle Einschätzungen Mehltauart Golovinomyces cichoracearum auf Gurken angebaut mit 18. Dieses Protokoll basiert auf einem Protokoll im Labor Gruppe B. Keller entwickelt (Universität Zürich, Zürich Schweiz) 13, 19und umfasst mehrere Modifikationen, die zu einem erhöhten DNA-Ausbeuten und einen höheren Anteil an DNA&gt; 48,5 kbp in Größe geführt. Das Protokoll enthält auch die Qualitätskontrolle Schritte basieren auf den Empfehlungen aus den Vereinigten Staaten Department of Energy Joint Genome Institute 20, 21, 22. Die Funktion jedes Reagenz in dem Lysepuffer enthalten ist , und die Gründe für jeden Reinigungsschritt werden , wie in Henry (2008) 23 beschrieben. Verfügbare veröffentlichte Protokolle zur Isolierung von hochmolekulare genomische DNA aus pflanzlichen und mikrobiellen Geweben wurden auch bei der Gestaltung dieses Protokolls 24, 25, 26 angehört, 27, 28.

<table><tbody><tr><td>MM400 Ball Mill</td><td>Retsch</td><td>20.745.0001</td><td>Or equivalent ball mill</td></tr><tr><td>2 mL tubes for ball milling</td><td>Sarstedt&amp;nbsp;</td><td>72.694.007</td><td></td></tr><tr><td>5/32&quot; stainless steel milling balls</td><td>OPS Diagnostics</td><td>GBSS 165-5000-01</td><td></td></tr><tr><td>Microprocessor controlled 280 Series Water Bath Preset to 65 &amp;deg;C&amp;nbsp;</td><td>Thermo Fisher Scientific</td><td>2825</td><td>Or equivalent water bath</td></tr><tr><td>Microprocessor controlled 280 Series Water Bath Preset to 37 &amp;deg;C</td><td>Thermo Fisher Scientific</td><td>2825</td><td>Or equivalent water bath</td></tr><tr><td>Eppendorf 5417R refrigerated microcentrifuge</td><td>Krakeler Scientific&amp;nbsp;</td><td>38-022621807</td><td>Or equivalent microcentrifuge</td></tr><tr><td>Chlorform:IAA (24:1 v/v)</td><td>Sigma-Aldrich&amp;nbsp;</td><td>C0549</td><td>Hazardous in case of skin contact or inhalation. Wear nitrile gloves, protective eyewear, lab coat and work in chemical hood</td></tr><tr><td>Phenol:Chloroform:IAA&lt;br /&gt; (25:24:1 v/v)</td><td>Thermo Fisher Scientific</td><td>15593031</td><td>Hazardous in case of skin contact or inhalation. Wear nitrile gloves, protective eyewear, lab coat and work in chemical hood</td></tr><tr><td>100% Isopropanol</td><td>Sigma-Aldrich&amp;nbsp;</td><td>W292907</td><td></td></tr><tr><td>100% Ethanol</td><td>Sigma-Aldrich&amp;nbsp;</td><td>34923</td><td>Chill to -20 &amp;deg;C prior use</td></tr><tr><td>Sodium Acetate</td><td>Sigma-Aldrich&amp;nbsp;</td><td>S2889</td><td></td></tr><tr><td>Rnase, Dnase-free (10 mg/mL)</td><td>Thermo Fisher Scientific</td><td>EN0531</td><td></td></tr><tr><td>Potassium metabisulfite</td><td>Sigma-Aldrich&amp;nbsp;</td><td>P2522</td><td></td></tr><tr><td>Sodium Lauryl Sacroinate</td><td>Sigma-Aldrich&amp;nbsp;</td><td>L9150</td><td></td></tr><tr><td>Tris base</td><td>Sigma-Aldrich&amp;nbsp;</td><td>10708976001</td><td></td></tr><tr><td>Ethylenediaminetetraacetic acid (EDTA)</td><td>Sigma-Aldrich&amp;nbsp;</td><td>EDS</td><td></td></tr><tr><td>Sodium chloride (NaCl)</td><td>Sigma-Aldrich&amp;nbsp;</td><td>S9888</td><td></td></tr><tr><td>Cetyltrimethyl ammonium bromide (CTAB)</td><td>Sigma-Aldrich&amp;nbsp;</td><td>H6269</td><td></td></tr><tr><td>Uvex by Honeywell Futura Goggles S345C, Uvextreme</td><td>Staples</td><td>423263</td><td>Or equivalent eyewear</td></tr><tr><td>High Five COBALT nitrile gloves, LARGE</td><td>Neta Scientific</td><td>HFG-N193</td><td>Or equivalent gloves</td></tr><tr><td>GelRed Nucleic Acid Gel Stain 10,000x in water</td><td>Biotium</td><td>41003</td><td></td></tr><tr><td>Ethidium Bromide 10 mg/mL</td><td>Biotium</td><td>40042</td><td>Hazardous in case of skin contact. Wear nitrile gloves and protective eyewear</td></tr><tr><td>Agarose Ultrapure Bioreagent</td><td>VWR International LLC</td><td>JT4063</td><td></td></tr><tr><td>GeneRuler 1 kb Plus DNA Ladder</td><td>Thermo Fisher Scientific</td><td>FERSM1332</td><td></td></tr><tr><td>8 - 48 kb CHEF DNA size standards</td><td>Bio-Rad</td><td>170-3707</td><td></td></tr><tr><td>Pippin Prep</td><td>Life Technologies Corporation</td><td>4472172</td><td>Or equivalent pulse-field gel aparatus</td></tr><tr><td>Whatman qualitative filter paper, Grade 1</td><td>Sigma-Aldrich&amp;nbsp;</td><td>WHA1001042</td><td>Or equivalent growth chamber</td></tr><tr><td>Percival Growth Chamber</td><td>Percival</td><td>AR66LXC9</td><td></td></tr><tr><td>NanoDrop 8000 UV-Vis Spectrophotometer</td><td>Thermo Fisher Scientific</td><td>ND-8000-GL</td><td>Or equivalent spectrophotometer</td></tr><tr><td>Quant-iT PicoGreen dsDNA Assay Kit</td><td>Thermo Fisher Scientific</td><td>P11496</td><td></td></tr><tr><td>TAE Buffer (Tris-acetate-EDTA) (50x)</td><td>Thermo Fisher Scientific</td><td>B49</td><td>Dilute 1/50 with water before use (to 1x)</td></tr><tr><td>TE Buffer</td><td>Thermo Fisher Scientific</td><td>12090015&amp;nbsp;</td><td></td></tr><tr><td>Tris-Borate-EDTA, 10x Solution (Electrophoresis)</td><td>Thermo Fisher Scientific</td><td>BP13334</td><td>Dilute 1/10 with water before use (to 1x)</td></tr><tr><td>Liquid Nitrogen</td><td></td><td></td><td>Liquid nitrogen (-196 &amp;deg;C) is a freezing hazard. It will also expand rapidly upon warming and should not keep in a tightly closed container</td></tr></tbody></table>

purification of high molecular weight genomic dna from powdery mildew for long-read sequencing

Die Echten Mehltaupilze sind eine Gruppe von wirtschaftlich bedeutenden pilzliche Pflanzenpathogene. Relativ wenig ist von gut entwickelten genetischen und genomischen Ressourcen auf einen Mangel auf Grund über die Molekularbiologie und Genetik dieser Erreger, teilweise bekannt. Diese Organismen haben große, sich wiederholende Genome, die gemacht haben Genom-Sequenzierung und Montage prohibitiv schwierig. Hier beschreiben wir Methoden zur Erfassung, Extraktion, Reinigung und Bewertung der Qualitätskontrolle von hochmolekularem genomischer DNA aus einem echten Mehltau - Arten, Golovinomyces cichoracearum. Das beschriebene Protokoll umfasst mechanische Störung durch eine optimierte Phenol / Chloroform-Extraktion genomische DNA gefolgt Sporen. Eine typische Ausbeute betrug 7 &amp; mgr; g DNA pro 150 mg Konidien. Die genomische DNA , die dieses Verfahren isoliert wird , verwendet , ist geeignet für die Lang lesen Sequenzierung (dh&gt; 48,5 kbp). Maßnahmen zur Qualitätskontrolle, die Größe, die Ausbeute und Reinheit der genomischen DNA, um sicherzustellen, sind auchin diesem Verfahren beschrieben. Die Sequenzierung der genomischen DNA der hier beschriebenen Qualität wird für die Montage und den Vergleich von mehreren Mehltau Genome, die wiederum erlauben zu einem besseren Verständnis führen wird und eine verbesserte Steuerung dieser landwirtschaftlichen Erreger.

Ein repräsentatives Beispiel für gereinigter genomischer DNA aus G. 60 ng cichoracearum auf einem Agarosegel unter Verwendung von Gelelektrophorese laufen und unter Verwendung von Pulsfeld - Gelelektrophorese sind in den 1 bzw. 2 gezeigt. Genomische DNA-Präparate, die verstreichen, geringfügig übergeben und die Qualitätskontrolle nicht vertreten sind. Genomische DNA-Präparate, die vollständig Qualitätskontrolle...

Watch this Scientific Journal Video about Purification of High Molecular Weight Genomic DNA from Powdery Mildew for Long-Read Sequencing at JoVE.com

Purification of High Molecular Weight Genomic DNA from Powdery Mildew for Long-Read Sequencing

Described here is a method for the extraction, purification, and quality control of genomic DNA from the obligate biotrophic fungal pathogen, powdery mildew, for use in long-read genome sequencing.

Reinigung von High Molecular Weight genomischer DNA aus Echten Mehltaus für Long-Read-Sequenzierung

The powdery mildew fungi are a group of economically important fungal plant pathogens. Relatively little is known about the molecular biology and genetics ...

purification-high-molecular-weight-genomic-dna-from-powdery-mildew

Research

JoVE Journal

Genetics

11.6K Aufrufe.  University of California Berkeley. Described here is a method for the extraction, purification, and quality control of genomic DNA from the obligate biotrophic fungal pathogen, powdery mildew, for use in long-read genome sequencing.

Serie: Purification of High Molecular Weight Genomic DNA from Powdery Mildew for Long-Read Sequencing

Optimization and Comparative Analysis of Plant Organellar DNA Enrichment Methods Suitable for Next-generation Sequencing

Plant organellar genomes contain large, repetitive elements that may undergo pairing or recombination to form complex structures and/or sub-genomic fragments. Organellar genomes also exist in admixtures within a given cell or tissue type (heteroplasmy), and an abundance of subtypes may change throughout development or when under stress (sub-stoichiometric shifting). Next-generation sequencing (NGS) technologies are required to obtain deeper understanding of organellar genome structure and function. Traditional sequencing studies use several methods to obtain organellar DNA: (1) If a large amount of starting tissue is used, it is homogenized and subjected to differential centrifugation and/or gradient purification. (2) If a smaller amount of tissue is used (i.e., if seeds, material, or space is limited), the same process is performed as in (1), followed by whole-genome amplification to obtain sufficient DNA. (3) Bioinformatics analysis can be used to sequence the total genomic DNA and to parse out organellar reads. All these methods have inherent challenges and tradeoffs. In (1), it may be difficult to obtain such a large amount of starting tissue; in (2), whole-genome amplification could introduce a sequencing bias; and in (3), homology between nuclear and organellar genomes could interfere with assembly and analysis. In plants with large nuclear genomes, it is advantageous to enrich for organellar DNA to reduce sequencing costs and sequence complexity for bioinformatics analyses. Here, we compare a traditional differential centrifugation method with a fourth method, an adapted CpG-methyl pulldown approach, to separate the total genomic DNA into nuclear and organellar fractions. Both methods yield sufficient DNA for NGS, DNA that is highly enriched for organellar sequences, albeit at different ratios in mitochondria and chloroplasts. We present the optimization of these methods for wheat leaf tissue and discuss major advantages and disadvantages of each approach in the context of sample input, protocol ease, and downstream application.

The comparison and optimization of two plant organellar DNA enrichment methods are presented: traditional differential centrifugation and fractionation of the total gDNA based on methylation status. We assess the resulting DNA quantity and quality, demonstrate performance in short-read next-generation sequencing, and discuss the potential for use in long-read single-molecule sequencing.

Optimierung und Vergleichsanalyse von pflanzlichen organellaren DNA-Anreicherungsmethoden Geeignet für die Sequenzierung der nächsten Generation

Plant organellar genomes contain large, repetitive elements that may undergo pairing or recombination to form complex structures and/or sub-genomic ...

Forschung

Genetik

Nanopore DNA Sequencing for Metagenomic Soil Analysis

This article describes the steps for construction of a DNA library from soil, preparation and use of the nanopore flow cell, and analysis of the DNA sequences identified using computer software. Nanopore DNA sequencing is a flexible technique that allows for rapid microbial genome sequencing to identify bacterial and viral species, to characterize bacterial strains, and to detect genetic mutations that confer resistance to antibiotics. The advantages of nanopore sequencing (NS) for life sciences include its low complexity, reduced cost, and rapid real-time sequencing of purified genomic DNA, PCR amplicons, cDNA samples, or RNA. NS is an example of "strand sequencing" which involves sequencing DNA by guiding a single stranded DNA molecule through a nanopore that is inserted into a synthetic polymer membrane. The membrane has an electrical current applied across it, so as the individual bases pass through the nanopore the electrical current is disrupted to varying degrees by the four nucleotide bases. The identification of each nucleotide occurs by detecting the characteristic modulation of the electrical current by the different bases as they pass through the nanopore. The NS system consists of a handheld, USB powered portable device and a disposable flow cell that contains a nanopore array. The portable device plugs into a standard laptop computer that reads and records the DNA sequence using computer software.

Nanopore technology for sequencing biomolecules has wide applications in the life sciences, including identification of pathogens, food safety monitoring, genomic analysis, metagenomic environmental monitoring, and characterization of bacterial antibiotic resistance. In this article, the procedure for metagenomic soil DNA sequencing for species identification using the nanopore sequencing technology is demonstrated.

Nanopore DNA-Sequenzierung für metagenomische Bodenanalyse

This article describes the steps for construction of a DNA library from soil, preparation and use of the nanopore flow cell, and analysis of the DNA ...

Umwelt

Novel Sequence Discovery by Subtractive Genomics

Subtractive genomics can be used in any research where the goal is to identify the sequence of a gene, protein, or general region that is embedded in a larger genomic context. Subtractive genomics enables a researcher to isolate a target sequence of interest (T) by comprehensive sequencing and subtracting out known genetic elements (reference, R). The method can be used to identify novel sequences such as mitochondria, chloroplasts, viruses, or germline restricted chromosomes, and is particularly useful when T cannot be easily isolated from R. Beginning with the comprehensive genomic data (R + T), the method uses Basic Local Alignment Search Tool (BLAST) against a reference sequence, or sequences, to remove the matching known sequences (R), leaving behind the target (T). For subtraction to work best, R should be a relatively complete draft that is missing T. Since sequences remaining after subtraction are tested through quantitative Polymerase Chain Reaction (qPCR), R does not need to be complete for the method to work. Here we link computational steps with experimental steps into a cycle that can be iterated as needed, sequentially removing multiple reference sequences and refining the search for T. The advantage of subtractive genomics is that a completely novel target sequence can be identified even in cases in which physical purification is difficult, impossible, or expensive. A drawback of the method is finding a suitable reference for subtraction and obtaining T-positive and negative samples for qPCR testing. We describe our implementation of the method in the identification of the first gene from the germline-restricted chromosome of zebra finch. In that case computational filtering involved three references (R), sequentially removed over three cycles: an incomplete genomic assembly, raw genomic data, and transcriptomic data.

The purpose of this protocol is to use a combination of computational and bench research to find novel sequences that cannot be easily separated from a co-purifying sequence, which may be only partially known.

Neue Sequenz Entdeckung durch subtraktive Genomics

Subtractive genomics can be used in any research where the goal is to identify the sequence of a gene, protein, or general region that is embedded in a ...

Genome-wide Analysis of Histone Modifications Distribution using the Chromatin Immunoprecipitation Sequencing Method in Magnaporthe oryzae

Chromatin immunoprecipitation sequencing (ChIP-seq) is a powerful and widely used molecular technique for mapping whole genome locations of transcription factors (TFs), chromatin regulators, and histone modifications, as well as detecting entire genomes for uncovering TF binding patterns and histone posttranslational modifications. Chromatin-modifying activities, such as histone methylation, are often recruited to specific gene regulatory sequences, causing localized changes in chromatin structures and resulting in specific transcriptional effects. The rice blast is a devastating fungal disease on rice throughout the world and is a model system for studying fungus-plant interaction. However, the molecular mechanisms in how the histone modifications regulate their virulence genes in Magnaporthe oryzae remain elusive. More researchers need to use ChIP-seq to study how histone epigenetic modification regulates their target genes. ChIP-seq is also widely used to study the interaction between protein and DNA in animals and plants, but it is less used in the field of plant pathology and has not been well developed. In this paper, we describe the experimental process and operation method of ChIP-seq to identify the genome-wide distribution of histone methylation (such as H3K4me3) that binds to the functional target genes in M. oryzae. Here, we present a protocol to analyze the genome-wide distribution of histone modifications, which can identify new target genes in the pathogenesis of M. oryzae and other filamentous fungi.

Genome-wide Analysis of Histone Modifications Distribution using the Chromatin Immunoprecipitation Sequencing Method in Magnaporthe oryzae

Here, we present a protocol to analyze the genome-wide distribution of histone modifications, which can identify new target genes in the pathogenesis of M. oryzae and other filamentous fungi.

Genomweite Analyse der Histonmodifikationsverteilung mit der Chromatin-Immunpräzipitationssequenzierungsmethode in Magnaporthe Oryzae

Chromatin immunoprecipitation sequencing (ChIP-seq) is a powerful and widely used molecular technique for mapping whole genome locations of transcription ...

Extraction of High Molecular Weight Genomic DNA from Soils and Sediments

The soil microbiome is a vast and relatively unexplored reservoir of genomic diversity and metabolic innovation that is intimately associated with nutrient and energy flow within terrestrial ecosystems. Cultivation-independent environmental genomic, also known as metagenomic, approaches promise unprecedented access to this genetic information with respect to pathway reconstruction and functional screening for high value therapeutic and biomass conversion processes. However, the soil microbiome still remains a challenge largely due to the difficulty in obtaining high molecular weight DNA of sufficient quality for large insert library production. Here we introduce a protocol for extracting high molecular weight, microbial community genomic DNA from soils and sediments. The quality of isolated genomic DNA is ideal for constructing large insert environmental genomic libraries for downstream sequencing and screening applications. 
The procedure starts with cell lysis. Cell walls and membranes of microbes are lysed by both mechanical (grinding) and chemical forces (&beta;-mercaptoethanol). Genomic DNA is then isolated using extraction buffer, chloroform-isoamyl alcohol and isopropyl alcohol. The buffers employed for the lysis and extraction steps include guanidine isothiocyanate and hexadecyltrimethylammonium bromide (CTAB) to preserve the integrity of the high molecular weight genomic DNA. Depending on your downstream application, the isolated genomic DNA can be further purified using cesium chloride (CsCl) gradient ultracentrifugation, which reduces impurities including humic acids. The first procedure, extraction, takes approximately 8 hours, excluding DNA quantification step. The CsCl gradient ultracentrifugation, is a two days process. During the entire procedure, genomic DNA should be treated gently to prevent shearing, avoid severe vortexing, and repetitive harsh pipetting.

A methodology to isolate high molecular weight and high quality genomic DNA from soil microbial community is described.

Extraktion von High Molecular Weight genomischer DNA aus Böden und Sedimenten

The soil microbiome is a vast and relatively unexplored reservoir of genomic diversity and metabolic innovation that is intimately associated with ...

Biologie

An Ultrahigh-throughput Microfluidic Platform for Single-cell Genome Sequencing

Sequencing technologies have undergone a paradigm shift from bulk to single-cell resolution in response to an evolving understanding of the role of cellular heterogeneity in biological systems. However, single-cell sequencing of large populations has been hampered by limitations in processing genomes for sequencing. In this paper, we describe a method for single-cell genome sequencing (SiC-seq) which uses droplet microfluidics to isolate, amplify, and barcode the genomes of single cells. Cell encapsulation in microgels allows the compartmentalized purification and tagmentation of DNA, while a microfluidic merger efficiently pairs each genome with a unique single-cell oligonucleotide barcode, allowing &gt;50,000 single cells to be sequenced per run. The sequencing data is demultiplexed by barcode, generating groups of reads originating from single cells. As a high-throughput and low-bias method of single-cell sequencing, SiC-seq will enable a broader range of genomic studies targeted at diverse cell populations.

Single-cell sequencing reveals genotypic heterogeneity in biological systems, but current technologies lack the throughput necessary for the deep profiling of community composition and function. Here, we describe a microfluidic workflow for sequencing &gt;50,000 single-cell genomes from diverse cell populations.

Eine höchste Durchsatz mikrofluidischen Plattform für einzellige Genom-Sequenzierung

Sequencing technologies have undergone a paradigm shift from bulk to single-cell resolution in response to an evolving understanding of the role of ...

Biotechnik

Ultra-long Read Sequencing for Whole Genomic DNA Analysis

Third generation single-molecule DNA sequencing technologies offer significantly longer read length that can facilitate the assembly of complex genomes and analysis of complex structural variants. Nanopore platforms perform single-molecule sequencing by directly measuring the current changes mediated by DNA passage through the pores and can generate hundreds of kilobase (kb) reads with minimal capital cost. This platform has been adopted by many researchers for a variety of applications. Achieving longer sequencing read lengths is the most critical factor to leverage the value of nanopore sequencing platforms. To generate ultra-long reads, special consideration is required to avoid DNA breakages and gain efficiency to generate productive sequencing templates. Here, we provide the detailed protocol of ultra-long DNA sequencing including high molecular weight (HMW) DNA extraction from fresh or frozen cells, library construction by mechanical shearing or transposase fragmentation, and sequencing on a nanopore device. From 20-25 &#181;g of HMW DNA, the method can achieve N50 read length of 50-70 kb with mechanical shearing and N50 of 90-100 kb read length with transposase mediated fragmentation. The protocol can be applied to DNA extracted from mammalian cells to perform whole genome sequencing for the detection of structural variants and genome assembly. Additional improvements on the DNA extraction and enzymatic reactions will further increase the read length and expand its utility.

Long-read sequences greatly facilitate the assembly of complex genomes and characterization of structural variation. We describe a method to generate ultra-long sequences by nanopore-based sequencing platforms. The approach adopts an optimized DNA extraction followed by modified library preparations to generate hundreds of kilobase reads with moderate coverage from human cells.

Ultra-lange lesen Sequenzierung für ganze genomische DNA-Analysen

Third generation single-molecule DNA sequencing technologies offer significantly longer read length that can facilitate the assembly of complex genomes ...

Extraction of High Molecular Weight DNA from Microbial Mats

Successful and accurate analysis and interpretation of metagenomic data is dependent upon the efficient extraction of high-quality, high molecular weight (HMW) community DNA. However, environmental mat samples often pose difficulties to obtaining large concentrations of high-quality, HMW DNA. Hypersaline microbial mats contain high amounts of extracellular polymeric substances (EPS)1 and salts that may inhibit downstream applications of extracted DNA. Direct and harsh methods are often used in DNA extraction from refractory samples. These methods are typically used because the EPS in mats, an adhesive matrix, binds DNA2,3 during direct lysis. As a result of harsher extraction methods, DNA becomes fragmented into small sizes4,5,6.
The DNA thus becomes inappropriate for large-insert vector cloning. In order to circumvent these limitations, we report an improved methodology to extract HMW DNA of good quality and quantity from hypersaline microbial mats. We employed an indirect method involving the separation of microbial cells from the background mat matrix through blending and differential centrifugation. A combination of mechanical and chemical procedures was used to extract and purify DNA from the extracted microbial cells. Our protocol yields approximately 2 &mu;g of HMW DNA (35-50 kb) per gram of mat sample, with an A260/280 ratio of 1.6. Furthermore, amplification of 16S rRNA genes7 suggests that the protocol is able to minimize or eliminate any inhibitory effects of contaminants. Our results provide an appropriate methodology for the extraction of HMW DNA from microbial mats for functional metagenomic studies and may be applicable to other environmental samples from which DNA extraction is challenging.

We provide an improved protocol for extracting high molecular weight DNA from hypersaline microbial mats. Microbial cells are separated from the mat matrix prior to DNA extraction and purification. This enhances the concentrations, quality, and size of the DNA. The protocol may be used for other refractory samples.

Extraktion von DNA mit hohem Molekulargewicht von mikrobiellen Matten

Successful and accurate analysis and interpretation of metagenomic data is dependent upon the efficient extraction  of high-quality, high molecular weight ...

Purifying the Impure: Sequencing Metagenomes and Metatranscriptomes from Complex Animal-associated Samples

The accessibility of high-throughput sequencing has revolutionized many fields of biology. In order to better understand host-associated viral and microbial communities, a comprehensive workflow for DNA and RNA extraction was developed. The workflow concurrently generates viral and microbial metagenomes, as well as metatranscriptomes, from a single sample for next-generation sequencing. The coupling of these approaches provides an overview of both the taxonomical characteristics and the community encoded functions. The presented methods use Cystic Fibrosis (CF) sputum, a problematic sample type, because it is exceptionally viscous and contains high amount of mucins, free neutrophil DNA, and other unknown contaminants. The protocols described here target these problems and successfully recover viral and microbial DNA with minimal human DNA contamination. To complement the metagenomics studies, a metatranscriptomics protocol was optimized to recover both microbial and host mRNA that contains relatively few ribosomal RNA (rRNA) sequences. An overview of the data characteristics is presented to serve as a reference for assessing the success of the methods. Additional CF sputum samples were also collected to (i) evaluate the consistency of the microbiome profiles across seven consecutive days within a single patient, and (ii) compare the consistency of metagenomic approach to a 16S ribosomal RNA gene-based sequencing. The results showed that daily fluctuation of microbial profiles without antibiotic perturbation was minimal and the taxonomy profiles of the common CF-associated bacteria were highly similar between the 16S rDNA libraries and metagenomes generated from the hypotonic lysis (HL)-derived DNA. However, the differences between 16S rDNA taxonomical profiles generated from total DNA and HL-derived DNA suggest that hypotonic lysis and the washing steps benefit in not only removing the human-derived DNA, but also microbial-derived extracellular DNA that may misrepresent the actual microbial profiles.

Using the cystic fibrosis airway as an example, the manuscript presents a comprehensive workflow comprising a combination of metagenomic and metatranscriptomic approaches to characterize the microbial and viral communities in animal-associated samples.

Reinigung der Unreine: Sequencing Metagenomen und Metatranscriptomes von Complex Tierassoziierte Proben

The accessibility of high-throughput sequencing has revolutionized many fields of biology. In order to better understand host-associated viral and ...

Genome-wide Purification of Extrachromosomal Circular DNA from Eukaryotic Cells

Extrachromosomal circular DNAs (eccDNAs) are common genetic elements in Saccharomyces cerevisiae and are reported in other eukaryotes as well. EccDNAs contribute to genetic variation among somatic cells in multicellular organisms and to evolution of unicellular eukaryotes. Sensitive methods for detecting eccDNA are needed to clarify how these elements affect genome stability and how environmental and biological factors&#160;induce their formation in eukaryotic cells. This video presents a sensitive eccDNA-purification method called Circle-Seq. The method encompasses column purification of circular DNA, removal of remaining linear chromosomal DNA, rolling-circle amplification of eccDNA, deep sequencing, and mapping. Extensive exonuclease treatment&#160;was&#160;required for sufficient linear chromosomal DNA degradation. The rolling-circle amplification step by &#966;29 polymerase enriched for circular DNA over linear DNA. Validation of the Circle-Seq method on three S. cerevisiae CEN.PK populations of 1010 cells detected hundreds of eccDNA profiles in sizes larger than 1 kilobase. Repeated findings of ASP3-1, COS111, CUP1, RSC30,&#160;HXT6, HXT7 genes on circular DNA in both S288c and CEN.PK suggests that DNA circularization is conserved between strains at these loci. In sum, the Circle-Seq method has broad applicability for genome-scale screening for eccDNA in eukaryotes as well as for detecting specific eccDNA types.

This paper presents a sensitive method called Circle-Seq for purifying extrachromosomal circular DNA (eccDNA). The method encompasses column purification, removal of remaining linear chromosomal DNA, rolling-circle amplification and high-throughput sequencing. Circle-Seq is applicable to genome-scale screening of eukaryotic eccDNA and studying genome instability and copy-number variation.

Genomweite Reinigung von extrachromosomale zirkuläre DNA aus eukaryotischen Zellen

Extrachromosomal circular DNAs (eccDNAs) are common genetic elements in Saccharomyces cerevisiae and are reported in other eukaryotes as well. EccDNAs ...