Name: genetic manipulation of the plant pathogen ustilago maydis to study fungal biology and plant microbe interactions
Uploaded: 2016-09-30T15:00:00.000+00:00
Duration: 11 min 42 s
Description: Watch this Scientific Journal Video about Genetic Manipulation of the Plant Pathogen Ustilago maydis to Study Fungal Biology and Plant Microbe Interactions at JoVE.com

תודה מיוחדת לד&quot;ר בנדיקט Steuten לקריאה ביקורתית של כתב היד. העבודה המקורית על chitinases בוצע על ידי ד&quot;ר תורסטן Langner. המעבדה של VG נתמך לפי האשכול של מצוינות למדעי הצמח (CEPLAS, DFG EXC 1028) ו BioSC, המעבדה של KS הוא נתמך על ידי BioSC. KB נתמך על ידי BioSC. הפעילות המדעית של מרכז המדע Bioeconomy (BioSC) נתמכו כלכלית על ידי משרד חדשנות, מדע ומחקר במסגרת של NRW Strategieprojekt BioSC (מס &#39;313 / 323-400-00213). LF נתמך על ידי דוקטורט של 1525 iGRADplant קבוצת הדרכת המחקר הבינלאומי DFG.

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The authors have nothing to disclose.

פרוטוקול זה מתאר כיצד ליצור מוטציות מחיקות למחקרים גנטיים הפוכים ב U. maydis. נקודת המוצא היא קונסטרוקציה המחיקה המכיל רצפים איגוף של הגן של ריבית המכיל רצפים של כ 1 קילו במעלה הזרם של ההתחלה במורד הזרם של תחנת-קודון וכן קלטת התנגדות מתאימה כפי שהוא היה מותאם בעבר ...

Ustilago maydis היא פטרייה מודל phytopathogenic כי נחקרה בהרחבה במשך עשרות שנים 1,2. היא קיימת בשני מורפולוגיות, שלב שמרים דמוי, שאינם פתוגניים וטופס filamentous, זיהומיות 3. תגליות פריצת דרך יוניברסל כגון מנגנוני רקומבינציה ותיקון DNA הומולוגיים נעשו בשלב הגדילה דמוי השמרים של פטריית 4 זו. יתר על כן, בורר מורפולוגיים לגורמי הנימה ארסי זיהומיות החשובים לזיהום הם היטב מאופיינים 5,6. הידע המולקולרי הגדיל אודות ביולוגיה ארסית של פטריית התועבה הזה מסתמך על אסטרטגיית התחדשות גן פשוט 7-9 הנתמך על ידי ביאור הגנום מעולה 10 ואת הקלות של גנטיקה הפוכה באמצעות, למשל, באוסף פלסמיד המאורגן היטב במכון שלנו (http : //www.mikrobiologie.hhu.de/ustilago-community.html). סטנדרטיים, מבחני זיהום מהירים של תירסeedlings לאפשר מחקרים מפורטים של פתוגניות גורמי 11. הגנום של U. maydis מכיל כ 6,900 גנים 10. כדי ללמוד את תפקידם, הם יכולים להימחק בנפרד או בשילוב בשל מערכת הומולוגית יעילה. אזורי איגוף של כ 1 kb המכילים קצוות הומולוגיים מושלם הם אידיאליים עבור שיעורים הומולוגיים יותר מ -50%, אבל כבר 250 נ&quot;ב עם קצוות שאינם הומולוגיים לאפשר מידה מסוימת של אינטגרציה הנכונה של המבנה 9. נכון לעכשיו, חמש קלטות התנגדות שונות, hygR, cbxR, natR, G418R, ו phleoR בתיווך התנגדות נגד hygromycin, carboxin, nourseothricin, G418 ו- phleomycin, מועסק כדי לבחור עבור transformants 7,9. בנוסף, התנגדות hygromycin כבר התפתחה קלטת למחזור (FRT-hygR) כי ניתן להסיר על ידי הביטוי החולף של recombinase FLP Heterologous 12. זה מאפשר סר של הקלטת התנגדות ובכך ב שינויים גנטיים בלתי מוגבלים תאוריה. Phleomycin הוא מוטגנים 13, כך שעם הקלטות החדשות, בפרט את קלטת hygR למחזור, שימוש phleoR הולך ופוחת. מוטציות Quadruple ולכן יכולות להיוצר באמצעות הקלטות הארבעה אחרים, אבל עבור מוטציות מחומשות, מערכת FRT-hygR מומלצת 14. אסטרטגיה מחיקת גן כללית זו הועברה בהצלחת פטריות תועבה אחרות כגון Sporisorium reilianum 15, ע &#39; 16 hordei, או U. אסכאלאנטה 17 ולכן מציע את הפוטנציאל עבור יישומים נוספים באורגניזמים עדיין גנטי סוררים עם מערכת הומולוגית יעילה. יתר על כן, אורגניזמים חסרי הומולוגיים יכול להיות שונה כדי לשפר את ההנדסה הגנטית כפי שהודגם על ידי מחיקה של גנים המעורבים שאינם הומולוגיים-אןד-מצטרף Neurospora crassa 18,19. כאן אנו מתארים את האסטרטגיה המחיקה גן שפורסם U. maydis 7,9 בפירוט הניסיון עם דגש על האימות המהירה ומדויקת של המועמדים. כדוגמא, אנו משתמשים chitinases פטרייתי מתארים את הדור של מוטציות יחידות, כמו גם מחיקת מספר זני 20,21. Chitinases הם דוגמאות מעניינות, כי הם פועלים על כיטין בקיר התא הנוקשה. שיפוץ דופן התא נדרש עבור שינויים מורפולוגיים במהלך חלוקת התא, לעבור לצמיחה פילמנטיות, ולאחר יצירת הנבגים. לפיכך, מוטנטים מחיקה פנוטיפים לאורך כל מחזור החיים ניתן לצפות.

<table><tbody><tr><td>Aminobenzoeic acid (Free Acid)</td><td>Sigma Aldrich</td><td>A-9878</td><td></td></tr><tr><td>Bacto agar&amp;nbsp;</td><td>BD</td><td>214010</td><td>alternatively use local supplier</td></tr><tr><td>Bacto peptone</td><td>BD</td><td>211677</td><td>alternatively use local supplier</td></tr><tr><td>Bacto yeast extract&amp;nbsp;</td><td>BD</td><td>212750</td><td>alternatively use local supplier</td></tr><tr><td>CaCl&lt;sub&gt;2&lt;/sub&gt;*2H&lt;sub&gt;2&lt;/sub&gt;O</td><td>Gr&amp;uuml;ssing GmbH</td><td>10234</td><td>alternatively use local supplier</td></tr><tr><td>Ca-Pantothenat (Hemi-Ca. salt)</td><td>Sigma Aldrich</td><td>P-2250</td><td></td></tr><tr><td>Carboxin&amp;nbsp;</td><td>Sigma Aldrich</td><td>45371</td><td></td></tr><tr><td>Casamino acids&amp;nbsp;</td><td>BD</td><td>223050</td><td></td></tr><tr><td>Cholinchlorid</td><td>Sigma Aldrich</td><td>C-1879</td><td></td></tr><tr><td>Citric acid</td><td>ChemSolute</td><td>24,321,000</td><td>alternatively use local supplier</td></tr><tr><td>CuSO&lt;sub&gt;4&lt;/sub&gt;*5H&lt;sub&gt;2&lt;/sub&gt;O</td><td>Fluka</td><td>61240</td><td>alternatively use local supplier</td></tr><tr><td>D(+)Sucrose&amp;nbsp;</td><td>Roth</td><td>4621.1</td><td>alternatively use local supplier</td></tr><tr><td>DNA degr. free acid&amp;nbsp;</td><td>Sigma-Aldrich</td><td>D-3159</td><td></td></tr><tr><td>EDTA</td><td>Sigma Aldrich</td><td>E4378</td><td></td></tr><tr><td>FeCl&lt;sub&gt;3&lt;/sub&gt;*6H&lt;sub&gt;2&lt;/sub&gt;O</td><td>Gr&amp;uuml;ssing GmbH</td><td>10288</td><td>alternatively use local supplier</td></tr><tr><td>Geneticin (G418) disulfate salt</td><td>Sigma Aldrich</td><td>A1720</td><td></td></tr><tr><td>Trichoderma lysing enzymes</td><td>Sigma Aldrich</td><td>L1412</td><td></td></tr><tr><td>D(+) Glucose</td><td>Caelo</td><td>2580</td><td>alternatively use local supplier</td></tr><tr><td>Glycerin&amp;nbsp;</td><td>Fisher Chemical</td><td>G065015</td><td>alternatively use local supplier</td></tr><tr><td>H&lt;sub&gt;3&lt;/sub&gt;BO&lt;sub&gt;3&lt;/sub&gt;</td><td>AppliChem</td><td>A2940</td><td>Dangerous substance. Please check manufacturer&#039;s safety instructions.</td></tr><tr><td>Heparin sodium salt</td><td>Sigma Aldrich</td><td>H3393-50KU</td><td></td></tr><tr><td>Hygromycin B-solution</td><td>Roth</td><td>1287.2</td><td>Dangerous substance.&amp;nbsp;</td></tr><tr><td>KCl</td><td>VWR</td><td>26764298</td><td>alternatively use local supplier</td></tr><tr><td>KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;</td><td>AppliChem</td><td>A3620</td><td>alternatively use local supplier</td></tr><tr><td>MgSO&lt;sub&gt;4&lt;/sub&gt; waterfree</td><td>Merck</td><td>7487-88-9</td><td>Water free is critical. Alternatively use local supplier</td></tr><tr><td>MnCl&lt;sub&gt;2&lt;/sub&gt;*4H&lt;sub&gt;2&lt;/sub&gt;O</td><td>AppliChem</td><td>A2087</td><td>alternatively use local supplier</td></tr><tr><td>myo-Inositol</td><td>Sigma Aldrich</td><td>I-5125</td><td></td></tr><tr><td>Na&lt;sub&gt;2&lt;/sub&gt;-EDTA*2H&lt;sub&gt;2&lt;/sub&gt;O</td><td>AppliChem</td><td>A2937</td><td>alternatively use local supplier</td></tr><tr><td>Na&lt;sub&gt;2&lt;/sub&gt;MoO&lt;sub&gt;4&lt;/sub&gt;*2H&lt;sub&gt;2&lt;/sub&gt;O</td><td>Roth</td><td>0274.2</td><td>alternatively use local supplier</td></tr><tr><td>Na&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;</td><td>Gr&amp;uuml;ssing GmbH</td><td>12174</td><td>alternatively use local supplier</td></tr><tr><td>NaCl</td><td>Fisher Chemical</td><td>S316060</td><td>alternatively use local supplier</td></tr><tr><td>NaOH</td><td>ChemSolute</td><td>13,751,000</td><td>alternatively use local supplier</td></tr><tr><td>NH&lt;sub&gt;4&lt;/sub&gt;NO&lt;sub&gt;3&lt;/sub&gt;</td><td>Roth</td><td>K299.1</td><td>alternatively use local supplier</td></tr><tr><td>Nicotinic acid (Free acid)</td><td>Sigma Aldrich</td><td>N-4126</td><td></td></tr><tr><td>Nourseothricin dihydrogen sulfate&amp;nbsp;&amp;nbsp;</td><td>Werner BioAgents</td><td>5,001,000</td><td></td></tr><tr><td>Nutrient broth&amp;nbsp;</td><td>Difco</td><td></td><td>local suppliers</td></tr><tr><td>Phenol:Chloroform:Isoamyl alcohol (25:24:1) pH 6.7</td><td>Sigma Aldrich</td><td>P3803</td><td>Dangerous substance. Please check manufacturer&#039;s safety instructions.</td></tr><tr><td>polyethylene glycol (PEG)</td><td>Sigma Aldrich</td><td>P-3640</td><td></td></tr><tr><td>Potassium acetate</td><td>AppliChem</td><td>121479</td><td>alternatively use local supplier</td></tr><tr><td>Pyridoxin (monohydrochlorid)</td><td>Sigma Aldrich</td><td>P-9755</td><td></td></tr><tr><td>Riboflavin&amp;nbsp;</td><td>Sigma Aldrich</td><td>R4500</td><td></td></tr><tr><td>RNaseA</td><td>Sigma Aldrich</td><td>R5503</td><td></td></tr><tr><td>SDS</td><td>Roth</td><td>Cn30.3</td><td>alternatively use local supplier</td></tr><tr><td>small syringe</td><td>BD</td><td>300300</td><td>alternatively use local supplier</td></tr><tr><td>sterile filter, 22 &amp;micro;m</td><td>VWR</td><td>28145-477</td><td>alternatively use local supplier</td></tr><tr><td>Sorbitol</td><td>Roth</td><td>6213.1</td><td>alternatively use local supplier</td></tr><tr><td>Thiamin-hydrochloride</td><td>Serva</td><td>36020.02</td><td>alternatively use local supplier</td></tr><tr><td>tri-Na-Citrate</td><td>Fisher Chemical</td><td>S332060</td><td>alternatively use local supplier</td></tr><tr><td>Tris- (hydroxymethyl) aminomethane</td><td>VWR</td><td>103156X</td><td>alternatively use local supplier</td></tr><tr><td>Tris hydrochloride</td><td>Roth</td><td>9090.4</td><td>alternatively use local supplier</td></tr><tr><td>Triton X-100&amp;nbsp;</td><td>Serva&amp;nbsp;</td><td>37240</td><td>alternatively use local supplier</td></tr><tr><td>ZnCl&lt;sub&gt;2&lt;/sub&gt;</td><td>Fluka</td><td>96470</td><td>alternatively use local supplier</td></tr><tr><td>Composition of solutions/preparation of material</td><td></td><td></td><td>Composition of solutions</td></tr><tr><td>Carboxin</td><td></td><td></td><td>Stock: 5 mg/ml in methanol, final concentration: 2 &amp;micro;g/ml</td></tr><tr><td>CM plates</td><td></td><td></td><td>0.25 % (w/v) Casamino acids, 0.1 % (w/v) Yeast Extract, 1.0 % (v/v) Holliday vitamin solution, 6.25 % (v/v); Holliday salt solution, 0.05 % (w/v) DNA degr. free acid, 0.15 % (w/v) NH&lt;sub&gt;4&lt;/sub&gt;NO&lt;sub&gt;3&lt;/sub&gt;, 2.0 % (w/v) Bacto Agar; adjust to pH 7.0 using 5 M NaOH; after autoclaving add 1 % glucose&amp;nbsp;</td></tr><tr><td>Geneticin (G418)</td><td></td><td></td><td>Stock: 50 mg/ml in H&lt;sub&gt;2&lt;/sub&gt;O, final concentration: 500 &amp;micro;g/ml</td></tr><tr><td>HCl-washed glass beads (0.35-0.45 mm)</td><td></td><td></td><td>Cover glass beads with concentrated HCl (25 %, 7.8 M) and incubate for 60 min. Sway several times. Decant HCl (keep decanted liquid) and wash glass beads with 3 M HCl (keep decanted liquid). Wash glass beads several times with double distilled H&lt;sub&gt;2&lt;/sub&gt;O until the pH is 7 (the liquid should not be yellow-green anymore). Aliquot the glass beads and dry them at 180 &amp;deg;C. The decanted HCl has to be neutralized before disposal.&amp;nbsp;</td></tr><tr><td>Heparin</td><td></td><td></td><td>Stock: 15 mg/ml</td></tr><tr><td>Holliday salt solution</td><td></td><td></td><td>16.0 &amp;permil; (w/v) KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;, 4.0 &amp;permil; (w/v) Na&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;, 8.0 &amp;permil; (w/v) KCl, 1.32 &amp;permil; (w/v) CaCl&lt;sub&gt;2&lt;/sub&gt;*2H&lt;sub&gt;2&lt;/sub&gt;O, 8.0 &amp;permil; (v/v) trace elements, 2.0 &amp;permil; (w/v) MgSO&lt;sub&gt;4&lt;/sub&gt;; sterile filtrate</td></tr><tr><td>Holliday vitamin solution&amp;nbsp;</td><td></td><td></td><td>0.1&amp;permil; (w/v) Thiamin, 0.05&amp;permil; (w/v) Riboflavin, 0.05&amp;permil; (w/v) Pyridoxin, 0.2&amp;permil; (w/v) Ca-Pantothenat, (0.05&amp;permil; (w/v) Aminobenzoeic acid, 0.2&amp;permil; (w/v) Nicotinic acid, 0.2&amp;permil; (w/v) Cholinchlorid, 1.0&amp;permil; (w/v) myo-Inositol; may be stored at -20 &amp;deg;C</td></tr><tr><td>Hygromycin</td><td></td><td></td><td>Stock: 50 mg/ml in PBS, final concentration: 200 &amp;micro;g/ml</td></tr><tr><td>Nourseothricin</td><td></td><td></td><td>Stock: 200 mg/ml in H&lt;sub&gt;2&lt;/sub&gt;O, final concentration: 150 &amp;micro;g/ml</td></tr><tr><td>NSY-glycerol-medium</td><td></td><td></td><td>0.8 % (w/v) Nutrient Broth, 0.1 % (w/v) Yeast Extract, 0.5 % (w/v) Sucrose,&amp;nbsp; 80.0 % (v/v) 87% Glycerin (f.c. 69.6%)&amp;nbsp;</td></tr><tr><td>RegLight</td><td></td><td></td><td>1.0% (w/v) Yeast Extract&amp;nbsp; 0.4 % (w/v) Bacto Peptone, 0.4 % (w/v) Sucrose, 18.22 % (w/v) Sorbitol, 1.5 % (w/v) Agar</td></tr><tr><td>SCS, pH 5.8</td><td></td><td></td><td>Solution 1: 20 mM tri-Na-citrate, 1 M Sorbitol; colution 2: 20 mM Citric acid, 1 M Sorbitol, add solution 2 into solution 1 until pH 5.8 is reached; autoclave</td></tr><tr><td>STC, pH 8</td><td></td><td></td><td>1 M Sorbitol, 10 mM Tris-HCl pH 7.5, 100 mM CaCl&lt;sub&gt;2&lt;/sub&gt;; filter sterile</td></tr><tr><td>STC/PEG</td><td></td><td></td><td>40 % (v/v) PEG in STC-buffer&amp;nbsp;</td></tr><tr><td>TE buffer, pH 8</td><td></td><td></td><td>1.31 mM Tris-Base, 8.69 mM Tris-HCl, 10 mM Na&lt;sub&gt;2&lt;/sub&gt;-EDTA*2H&lt;sub&gt;2&lt;/sub&gt;O</td></tr><tr><td>TE/RNase</td><td></td><td></td><td>10 &amp;micro;g/ml RNaseA in TE buffer</td></tr><tr><td>Trace elements</td><td></td><td></td><td>0.06&amp;permil; (w/v) H&lt;sub&gt;3&lt;/sub&gt;BO&lt;sub&gt;3&lt;/sub&gt;, 0.14&amp;permil; (w/v) MnCl*4H&lt;sub&gt;2&lt;/sub&gt;O, 0.4 &amp;permil; (w/v) ZnCl&lt;sub&gt;2&lt;/sub&gt;, 0.4 &amp;permil; (w/v) Na&lt;sub&gt;2&lt;/sub&gt;MoO&lt;sub&gt;4&lt;/sub&gt;*H2O:2, 0.1 &amp;permil; (w/v) FeCl&lt;sub&gt;3&lt;/sub&gt;*6H&lt;sub&gt;2&lt;/sub&gt;O, 0.04&amp;permil; (w/v) CuSO&lt;sub&gt;4&lt;/sub&gt;*5H&lt;sub&gt;2&lt;/sub&gt;O</td></tr><tr><td>Trichoderma lysing enzymes solution</td><td></td><td></td><td>12.5 mg/ml SCS; filter sterile; prepare shortly before use</td></tr><tr><td>Tris-HCl pH 7.5</td><td></td><td></td><td>806 mM Tris-HCl, 194 mM Tris-Base; check the pH and if necessary adjust with HCl; autoclave</td></tr><tr><td>Usti-lysis buffer 1, pH 8</td><td></td><td></td><td>10 mM Tris-HCl (pH 8.0), 10 mM NaCl, 1% (w/v) SDS, 2% (v/v) TritonX-100, 1 mM EDTA. Do not measure pH using pH meter.&amp;nbsp;</td></tr><tr><td>Usti-lysis buffer 2</td><td></td><td></td><td>mix Usti lysis buffer 1 with 1x TE in a 1:1 ratio</td></tr><tr><td>YEPS-Light medium</td><td></td><td></td><td>1.0% (w/v) Yeast Extract, 0.4% (w/v) Bacto Peptone, 0.4% (w/v) Sucrose, for plates: 1.5% (w/v) Bacto Agar</td></tr></tbody></table>

genetic manipulation of the plant pathogen ustilago maydis to study fungal biology and plant microbe interactions

מחיקת ג&#39;ין ממלאת תפקיד חשוב בניתוח של תפקוד גן. אחת השיטות היעילות ביותר לשבש גנים באופן ממוקד הוא החלפת הגן כולו עם סמן לבחירה באמצעות רקומבינציה הומולוגי. במהלך הומולוגי, חילופי DNA מתרחשים בין רצפים עם דמיון גבוה. לכן, רצפי הגנום ליניארי איגוף גן מטרה ניתן להשתמש כדי לכוון סמן לבחירה במיוחד לאתר אינטגרציה הרצוי. קצוות בלאנט של לבנות את המחיקה להפעיל את מערכות תיקון דנ&quot;א של התא ובכך לקדם אינטגרציה של המבנה או דרך רקומבינציה הומולוגי או שאינו הומולוגיים סוף-שהצטרף. באורגניזמים עם הומולוגיים יעילים, שיעור מחיקת גן מוצלח יכול להגיע ליותר מ -50% ביצוע אסטרטגיה זו מערכת שיבוש הגנטי יקרה. פטריית התועבה Ustilago maydis היא מיקרואורגניזם מודל אוקריוטים מראה recombinat הומולוגי יעיל כזהיוֹן. מתוך שלה על 6,900 גנים, רבים מתאפיינים תפקודי בעזרת מוטציות מחיקות, וחזר על כישלון נקודות ניסיונות החלפת גן על תפקוד חיוני של הגן. האפיון הבא של תפקוד הגן על ידי תיוג עם סמני ניאון או מוטציות של תחומים ניבאו גם מסתמך על חילופי דנ&quot;א באמצעות רקומבינציה הומולוגי. כאן, אנו מציגים את U. דור אסטרטגית זן maydis בפירוט באמצעות הדוגמא הפשוטה ביותר, את מחיקת הגן.

הקונסטרוקציות המחיקות של כל ארבעת הגנים chitinolytic רשומים U. הגנום maydis נוצרו על ידי שיבוט גולדן גייט באמצעות קלטת hygR למחיקה של cts1, את natR למחיקה של cts2, הקלטת G418R למחיקה של cts3 ואת cbxR למחיקה של cts4 20. סקירה...

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Genetic Manipulation of the Plant Pathogen Ustilago maydis to Study Fungal Biology and Plant Microbe Interactions

אנו מתארים אסטרטגית החלפת גנים חזקה כדי גנטי לתפעל פטריית תועבת Ustilago maydis. פרוטוקול זה מסביר כיצד ליצור מוטציות מחיקות לחקור פנוטיפים זיהום. זה יכול להתארך עד לשנות את הגנים בכל דרך רצויה, למשל, על ידי הוספת רצף קידוד תג חלבון פלואורסצנטי.

מניפולציה גנטית של פתוגן הצמח<em&gt; Ustilago maydis</em&gt; ללמוד ביולוגיה פטרייתי אינטראקציות חיידק צמח

Gene deletion plays an important role in the analysis of gene function. One of the most efficient methods to disrupt genes in a targeted manner is the ...

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Research

JoVE Journal

Genetics

Genetic Manipulation of the Plant Pathogen Ustilago maydis to Study Fungal Biology and Plant Microbe Interactions

14.4K Views.  Heinrich-Heine University Düsseldorf.  אנו מתארים אסטרטגית החלפת גנים חזקה כדי גנטי לתפעל פטריית תועבת Ustilago maydis. פרוטוקול זה מסביר כיצד ליצור מוטציות מחיקות לחקור פנוטיפים זיהום. זה יכול להתארך עד לשנות את הגנים בכל דרך רצויה, למשל, על ידי הוספת רצף קידוד תג חלבון פלואו...

Video: Genetic Manipulation of the Plant Pathogen Ustilago maydis to Study Fungal Biology and Plant Microbe Interactions

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

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

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

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

שיטה מהירה ויעילה להערכת פתוגניות של מיאדי אוסטילגו על קווי תירס וטוסינטה

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

Environment

Rapid Deletion Production in Fungi via Agrobacterium Mediated Transformation of OSCAR Deletion Constructs

Precise deletion of gene(s) of interest, while leaving the rest of the genome unchanged, provides the ideal product to determine that particular gene&#39;s function in the living organism. In this protocol the OSCAR method of precise and rapid deletion plasmid construction is described. OSCAR relies on the cloning system in which a single recombinase reaction is carried out containing the purified PCR-amplified 5&#39; and 3&#39; flanks of the gene of interest and two plasmids, pA-Hyg OSCAR (the marker vector) and pOSCAR (the assembly vector). Confirmation of the correctly assembled deletion vector is carried out by restriction digestion mapping followed by sequencing. Agrobacterium tumefaciens is then used to mediate introduction of the deletion construct into fungal spores (referred to as ATMT). Finally, a PCR assay is described to determine if the deletion construct integrated by homologous or non-homologous recombination, indicating gene deletion or ectopic integration, respectively. This approach has been successfully used for deletion of numerous genes in Verticillium dahliae and in Fusarium verticillioides among other species.

Rapid Deletion Production in Fungi via Agrobacterium Mediated Transformation of OSCAR Deletion Constructs

Gene deletion mutants generated through homologous recombination are the gold standard for gene function studies. The OSCAR (One Step Construction of Agrobacterium-Recombination-ready-plasmids) method for rapid generation of deletion constructs is described. Agrobacterium mediated fungal transformation follows. Finally, a PCR based confirmation method of gene deletions in fungal transformants is presented.

הפקה מהירה מחיקת פטריות דרך<em&gt; Agrobacterium</em&gt; שינוי מתווך של OSCAR מחיקת מבנים

Precise deletion of gene(s) of interest, while leaving the rest of the genome unchanged, provides the ideal product to determine that particular ...

Using Ustilago maydis as a Trojan Horse for In Situ Delivery of Maize Proteins

Inspired by Homer&#180;s Trojan horse myth, we engineered the maize pathogen Ustilago maydis to deliver secreted proteins into the maize apoplast permitting in vivo phenotypic analysis. This method does not rely on maize transformation but exploits microbial genetics and secretory capabilities of pathogens. Herein, it allows inspection of in vivo delivered secreted proteins with high spatiotemporal resolution at different kinds of infection sites and tissues. The Trojan horse strategy can be utilized to transiently complement maize loss-of-function phenotypes, to functionally characterize protein domains, to analyze off-target protein effects, or to study onside protein overdosage, making it a powerful tool for protein studies in the maize crop system. This work contains a precise protocol on how to generate a Trojan horse strain followed by standardized infection protocols to apply this method to three different maize tissue types.

Using Ustilago maydis as a Trojan Horse for In Situ Delivery of Maize Proteins

This work describes the cloning of an Ustilago maydis Trojan horse strain for the in situ delivery of secreted maize proteins into three different types of maize tissues.

בעזרת פחמון זקן התירס כמו סוס טרויאני ב באתרו משלוח של תירס חלבונים

Inspired by Homer&#180;s Trojan horse myth, we engineered the maize pathogen Ustilago maydis to deliver secreted proteins into the maize apoplast ...

CRISPR-mediated Genome Editing of the Human Fungal Pathogen Candida albicans

This method describes the efficient CRISPR mediated genome editing of the diploid human fungal pathogen Candida albicans. CRISPR-mediated genome editing in C. albicans requires Cas9, guide RNA, and repair template. A plasmid expressing a yeast codon optimized Cas9 (CaCas9) has been generated. Guide sequences directly upstream from a PAM site (NGG) are cloned into the Cas9 expression vector. A repair template is then made by primer extension in vitro. Cotransformation of the repair template and vector into C. albicans leads to genome editing. Depending on the repair template used, the investigator can introduce nucleotide changes, insertions, or deletions. As C. albicans is a diploid, mutations are made in both alleles of a gene, provided that the A and B alleles do not harbor SNPs that interfere with guide targeting or repair template incorporation. Multimember gene families can be edited in parallel if suitable conserved sequences exist in all family members. The C. albicans CRISPR system described is flanked by FRT sites and encodes flippase. Upon induction of flippase, the antibiotic marker (CaCas9) and guide RNA are removed from the genome. This allows the investigator to perform subsequent edits to the genome. C. albicans CRISPR is a powerful fungal genetic engineering tool, and minor alterations to the described protocols permit the modification of other fungal species including C. glabrata, N. castellii, and S. cerevisiae.

CRISPR-mediated Genome Editing of the Human Fungal Pathogen Candida albicans

Efficient genome engineering of Candida albicans is critical to understanding the pathogenesis and development of therapeutics. Here, we described a protocol to quickly and accurately edit the C. albicans genome using CRISPR. The protocol allows investigators to introduce a wide variety of genetic modifications including point mutations, insertions, and deletions.

בתיווך CRISPR הגנום עריכה של פטריות פתוגניות קנדידה אלביקנס

This method describes the efficient CRISPR mediated genome editing of the diploid human fungal pathogen Candida albicans. CRISPR-mediated genome editing ...

Inhibition of Aspergillus flavus Growth and Aflatoxin Production in Transgenic Maize Expressing the &#945;-amylase Inhibitor from Lablab purpureus L.

Aflatoxin contamination in food and feed crops is a major challenge worldwide. Aflatoxins, produced by the fungus Aspergillus flavus (A. flavus) are potent carcinogens that substantially reduce crop value in maize and other oil rich crops like peanut besides posing serious threat to human and animal health. Different approaches, including traditional breeding, transgenic expression of resistance associated proteins, and RNA interference (RNAi)-based host-induced gene silencing of critical A. flavus gene targets, are being evaluated to increase aflatoxin resistance in susceptible crops. Past studies have shown an important role of &#945;-amylase in A. flavus pathogenesis and aflatoxin production, suggesting this gene/enzyme is a potential target to reduce both A. flavus growth and aflatoxin production. In this regard, the current study was undertaken to evaluate heterologous expression (under control of the constitutive CaMV 35S promoter) of a Lablab purpureus L. &#945;-amylase inhibitor-like protein (AILP) in maize against A. flavus. AILP is a 36-kDa protein, which is a competitive inhibitor of A. flavus &#945;-amylase enzyme and belongs to the lectin&#8211;arcelin&#8211;&#945;-amylase inhibitor protein family in common bean. In vitro studies prior to the current work had demonstrated the role of AILP in inhibition of A. flavus &#945;-amylase activity and fungal growth. Fungal growth and aflatoxin production in mature kernels were monitored in real time using a GFP-expressing A. flavus strain. This kernel screening assay (KSA) is very simple to set up and provides reliable and reproducible data on infection and the extent of spread that could be quantified for evaluation of germplasm and transgenic lines. The fluorescence from the GFP strain is closely correlated to fungal growth and, by extension, it is well-correlated to aflatoxin values.&#160; The goal of the current work was to implement this previous knowledge in a commercially important crop like maize to increase aflatoxin resistance. Our results show a 35%&#8211;72% reduction in A. flavus growth in AILP-expressing transgenic maize kernels which, in turn, translated into a 62%&#8211;88% reduction in aflatoxin levels.

Inhibition of Aspergillus flavus Growth and Aflatoxin Production in Transgenic Maize Expressing the &#945;-amylase Inhibitor from Lablab purpureus L.

Here we present a protocol to analyze Aspergillus flavus growth and aflatoxin production in maize kernels expressing an antifungal protein.&#160; Using a GFP-expressing A. flavus strain we monitored the infection and spread of the fungus in mature kernels in real time. The assay is rapid, reliable, and reproducible.

עיכוב של צמיחה אספרגילוס flavus Aflatoxin ייצור הטרנסגניים תירס לבטא מעכב α-עמילאז מן Lablab purpureus ל'

Aflatoxin contamination in food and feed crops is a major challenge worldwide. Aflatoxins, produced by the fungus Aspergillus flavus (A. flavus) are ...

Genetic Manipulation in &Delta;ku80 Strains for Functional Genomic Analysis of Toxoplasma gondii

Targeted genetic manipulation using homologous recombination is the method of choice for functional genomic analysis to obtain a detailed view of gene function and phenotype(s). The development of mutant strains with targeted gene deletions, targeted mutations, complemented gene function, and/or tagged genes provides powerful strategies to address gene function, particularly if these genetic manipulations can be efficiently targeted to the gene locus of interest using integration mediated by double cross over homologous recombination.
Due to very high rates of nonhomologous recombination, functional genomic analysis of Toxoplasma gondii has been previously limited by the absence of efficient methods for targeting gene deletions and gene replacements to specific genetic loci. Recently, we abolished the major pathway of nonhomologous recombination in type I and type II strains of T. gondii by deleting the gene encoding the KU80 protein1,2. The &Delta;ku80 strains behave normally during tachyzoite (acute) and bradyzoite (chronic) stages in vitro and in vivo and exhibit essentially a 100% frequency of homologous recombination. The &Delta;ku80 strains make functional genomic studies feasible on the single gene as well as on the genome scale1-4.
Here, we report methods for using type I and type II &Delta;ku80&Delta;hxgprt strains to advance gene targeting approaches in T. gondii. We outline efficient methods for generating gene deletions, gene replacements, and tagged genes by targeted insertion or deletion of the hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) selectable marker. The described gene targeting protocol can be used in a variety of ways in &Delta;ku80 strains to advance functional analysis of the parasite genome and to develop single strains that carry multiple targeted genetic manipulations. The application of this genetic method and subsequent phenotypic assays will reveal fundamental and unique aspects of the biology of T. gondii and related significant human pathogens that cause malaria (Plasmodium sp.) and cryptosporidiosis (Cryptosporidium).

Here we report a method for using type I and type II &Delta;ku80 strains of Toxoplasma gondii to efficiently generate targeted gene deletions and gene replacements for functional genomic analysis.

מניפולציה גנטית ב<em&gt; Δku80</em&gt; זנים לאנליזה גנומית תפקודית של<em&gt; Toxoplasma gondii</em

Targeted genetic manipulation using homologous recombination is the method of choice for functional genomic analysis to obtain a detailed view of gene ...

Immunology and Infection

CRISPR-Cas9-Mediated Genome Editing in the Filamentous Ascomycete Huntiella omanensis

The CRISPR-Cas9 genome editing system is a molecular tool that can be used to introduce precise changes into the genomes of model and non-model species alike. This technology can be used for a variety of genome editing approaches, from gene knockouts and knockins to more specific changes like the introduction of a few nucleotides at a targeted location. Genome editing can be used for a multitude of applications, including the partial functional characterization of genes, the production of transgenic organisms and the development of diagnostic tools. Compared to previously available gene editing strategies, the CRISPR-Cas9 system has been shown to be easy to establish in new species and boasts high efficiency and specificity. The primary reason for this is that the editing tool uses an RNA molecule to target the gene or sequence of interest, making target molecule design straightforward, given that standard base pairing rules can be exploited. Similar to other genome editing systems, CRISPR-Cas9-based methods also require efficient and effective transformation protocols as well as access to good quality sequence data for the design of the targeting RNA and DNA molecules. Since the introduction of this system in 2013, it has been used to genetically engineer a variety of model species, including Saccharomyces cerevisiae, Arabidopsis thaliana, Drosophila melanogaster and Mus musculus. Subsequently, researchers working on non-model species have taken advantage of the system and used it for the study of genes involved in processes as diverse as secondary metabolism in fungi, nematode growth and disease resistance in plants, among many others. This protocol detailed below describes the use of the CRISPR-Cas9 genome editing protocol for the truncation of a gene involved in the sexual cycle of Huntiella omanensis, a filamentous ascomycete fungus belonging to the Ceratocystidaceae family.

CRISPR-Cas9-Mediated Genome Editing in the Filamentous Ascomycete Huntiella omanensis

The CRISPR-Cas9 genome editing system is an easy-to-use genome editor that has been used in model and non-model species. Here we present a protein-based version of this system that was used to introduce a premature stop codon into a mating gene of a non-model filamentous ascomycete fungus.

CRISPR-Cas9-מתווכת עריכת גנום ב- Ascomycete ההאנטילה אומנסיס נימה

The CRISPR-Cas9 genome editing system is a molecular tool that can be used to introduce precise changes into the genomes of model and non-model species ...

Microfluidic Tools for Probing Fungal-Microbial Interactions at the Cellular Level

Filamentous fungi are successful inhabitants of soil and play a major role in soil ecosystems, such as in the decomposition of organic and inorganic matter, as well as regulation of nutrient levels. There they also find numerous opportunities to interact with a variety of other microbes such as bacteria or other fungi. Studying fungal interactions at the cellular level, however, can be challenging owing to the black box-like nature of soil. New microfluidic tools are being developed for the study of fungal interactions; two platforms designed to study bacterial-fungal and fungal-fungal interactions are highlighted. Within these microchannels, fungal-microbial interactions can be monitored in controlled physico-chemical environments at higher temporal and spatial resolution than previously possible. Application of these tools have yielded numerous novel biological insights, such as the observation of bacterial polar attachment to hyphae or revealing uncharacterised fungal-fungal antagonisms. A key feature of these methodologies regards the ease of use of this tool by non-experts, yielding highly translatable technologies for use in microbiology labs.

Owing to the opacity of soil, interactions between its constituent microbes cannot easily be visualised with cellular resolution. Here, two microfluidic tools are presented, which offer new opportunities for investigating fungal-microbial interactions. The devices are versatile and simple to use, enabling high spatiotemporal control and high-resolution imaging at the cellular level.

כלים מיקרופלואידיים לחקר אינטראקציות פטרייתיות-מיקרוביאליות ברמה התאית

Filamentous fungi are successful inhabitants of soil and play a major role in soil ecosystems, such as in the decomposition of organic and inorganic ...

Bioengineering

A Hydroponic Co-cultivation System for Simultaneous and Systematic Analysis of Plant/Microbe Molecular Interactions and Signaling

An experimental design mimicking natural plant-microbe interactions is very important to delineate the complex plant-microbe signaling processes. Arabidopsis thaliana-Agrobacterium tumefaciens provides an excellent model system to study bacterial pathogenesis and plant interactions. Previous studies of plant-Agrobacterium interactions have largely relied on plant cell suspension cultures, the artificial wounding of plants, or the artificial induction of microbial virulence factors or plant defenses by synthetic chemicals. However, these methods are distinct from the natural signaling in planta, where plants and microbes recognize and respond in spatial and temporal manners. This work presents a hydroponic cocultivation system where intact plants are supported by metal mesh screens and cocultivated with Agrobacterium. In this cocultivation system, no synthetic phytohormone or chemical that induces microbial virulence or plant defense is supplemented. The hydroponic cocultivation system closely resembles natural plant-microbe interactions and signaling homeostasis in planta. Plant roots can be separated from the medium containing Agrobacterium, and the signaling and responses of both the plant hosts and the interacting microbes can be investigated simultaneously and systematically. At any given timepoint/interval, plant tissues or bacteria can be harvested separately for various &#34;omics&#34; analyses, demonstrating the power and efficacy of this system. The hydroponic cocultivation system can be easily adapted to study: 1) the reciprocal signaling of diverse plant-microbe systems, 2) signaling between a plant host and multiple microbial species (i.e.&#160;microbial consortia or microbiomes), 3) how nutrients and chemicals are implicated in plant-microbe signaling, and 4) how microbes interact with plant hosts and contribute to plant tolerance to biotic or abiotic stresses.

The described hydroponic cocultivation system supports intact plants with metal mesh screens and cocultivates them with bacteria. Plant tissue, bacteria, and secreted molecules can then be separately harvested for downstream analyses, simultaneously allowing for the molecular responses of both plant hosts and interacting microbes or microbiomes to be investigated.

הידרופוני Co- טיפוח מערכת לניתוח סימולטני ושיטתי של הצמח / מיקרובי אינטראקציות מולקולרית איתות

An experimental design mimicking natural plant-microbe interactions is very important to delineate the complex plant-microbe signaling processes. ...

Biology

Investigating Teliospore Germination Using Microrespiration Analysis and Microdissection

Smut fungi are the etiological agents of several devastating agricultural diseases. They are characterized by the production of teliospores, which are thick-walled dispersal agents. Teliospores can remain dormant for decades. The dormancy is characterized by low metabolic rates, paused macromolecular biosynthesis and greatly reduced levels of respiration. Upon receiving required environmental signals, teliospores germinate to produce haploid cells, which can initiate new rounds of infection. Teliospore germination is characterized by the resumption of macromolecular biosynthesis, increased respiration and dramatic morphological changes. In order to precisely measure changes in cellular respiration during the early stages of germination, we have developed a simple protocol employing a Clark-type respirometer. The later stages of germination are distinguished by specific morphological changes, but germination is asynchronous. We developed a microdissection technique that enables us to collect teliospores at distinct germination stages.

Smut fungi cause many devastating agricultural diseases. They are dispersed as dormant teliospores that germinate in response to environmental cues. We outline two methods to investigate molecular changes during germination: measuring respiration increase to detect metabolic activation and assessing changing molecular events by isolating teliospores at distinct morphological stages.

חוקרים נביטה Teliospore באמצעות ניתוח Microrespiration ו- Microdissection

Smut fungi are the etiological agents of several devastating agricultural diseases. They are characterized by the production of teliospores, which are ...

מניפולציה גנטית של פתוגן הצמח

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