The authors thank Dr. Dario Bonetta for providing Arabidopsis thaliana seeds and for technical assistance in regards to the triple response assay, as well as Simone Quaranta for help with FT-IR. This work was supported by a Natural Sciences and Engineering Research Council of Canada Discovery Grant (NSERC-DG) to JLS, an Ontario Graduate Scholarship (OGS) to RVA, and a Queen Elizabeth II Graduate Scholarship in Science and Technology (QEII-GSST) to AJV.

<ol>
	<li>Guzm&#225;n, P., Ecker, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exploiting+the+triple+response+of+Arabidopsis+to+identify+ethylene-related+mutants.">Exploiting the triple response of Arabidopsis to identify ethylene-related mutants.</a> Plant Cell. 2 (6), 513-523 (1990).</li><li>Bakshi, A., Shemansky, J. M., Chang, C., Binder, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=History+of+research+on+the+plant+hormone+ethylene.">History of research on the plant hormone ethylene.</a> J. Plant Growth Regul. 34 (4), 809-827 (2015).</li><li>Schaller, G. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethylene+and+the+regulation+of+plant+development.">Ethylene and the regulation of plant development.</a> BMC Biol. 10 (1), (2012).</li><li>Hua, J., Sakai, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EIN4+and+ERS2+are+members+of+the+putative+ethylene+receptor+gene+family+in+Arabidopsis.">EIN4 and ERS2 are members of the putative ethylene receptor gene family in Arabidopsis.</a> Plant Cell. 10 (8), 1321-1332 (1998).</li><li>Bleecker, A. B., Estelle, M. A., Somerville, C., Kende, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insensitivity+to+ethylene+conferred+by+a+dominant+Mutation+in+Arabidopsis+thaliana.">Insensitivity to ethylene conferred by a dominant Mutation in Arabidopsis thaliana.</a> Science. 241 (4869), 1086-1089 (1988).</li><li>Hamilton, A. J., Bouzayen, M., Grierson, D. <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+a+tomato+gene+for+the+ethylene-forming+enzyme+by+expression+in+yeast.">Identification of a tomato gene for the ethylene-forming enzyme by expression in yeast.</a> Proc. Natl. Acad. Sci. 88 (16), 7434-7437 (1991).</li><li>Kim, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+ethylene+removal+with+Pseudomonas+strains.">Assessment of ethylene removal with Pseudomonas strains.</a> J. Hazard. Mater. 131 (3), 131-136 (2006).</li><li>Kim, H. E., Shitashiro, M., Kuroda, A., Takiguchi, N., Kato, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethylene+chemotaxis+in+Pseudomonas+aeruginosa+and+other+Pseudomonas+species.">Ethylene chemotaxis in Pseudomonas aeruginosa and other Pseudomonas species.</a> Microbes Environ. 22 (2), 186-189 (2007).</li><li>Augimeri, R. V., Strap, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+phytohormone+ethylene+enhances+bacterial+cellulose+production,+regulates+CRP/FNRKx+transcription+and+causes+differential+gene+expression+within+the+cellulose+synthesis+operon+of+Komagataeibacter+(Gluconacetobacter)+xylinus+ATCC+53582.">The phytohormone ethylene enhances bacterial cellulose production, regulates CRP/FNRKx transcription and causes differential gene expression within the cellulose synthesis operon of Komagataeibacter (Gluconacetobacter) xylinus ATCC 53582.</a> Front. Microbiol. 6, 1459 (2015).</li><li>Zhang, W., Wen, C. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+of+ethylene+gas+and+comparison+of+ethylene+responses+induced+by+ethylene,+ACC,+and+ethephon.">Preparation of ethylene gas and comparison of ethylene responses induced by ethylene, ACC, and ethephon.</a> Plant Physiol. Biochem. 48 (1), 45-53 (2010).</li><li>Zhang, W., Hu, W., Wen, C. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethylene+preparation+and+its+application+to+physiological+experiments.">Ethylene preparation and its application to physiological experiments.</a> Plant Signal. Behav. 5 (4), 453-457 (2010).</li><li>Warner, H. L., Leopold, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethylene+evolution+from+2-chloroethylphosphonic+acid.">Ethylene evolution from 2-chloroethylphosphonic acid.</a> Plant Physiol. 44 (1), 156-158 (1969).</li><li>Biddle, E., Kerfoot, D. G. S., Kho, Y. H., Russell, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetic+studies+of+the+thermal+decomposition+of+2-chloroethylphosphonic+acid+in+aqueous+solution.">Kinetic studies of the thermal decomposition of 2-chloroethylphosphonic acid in aqueous solution.</a> Plant Physiol. 58 (5), 700-702 (1976).</li><li>Klein, I., Lavee, S., Ben-Tal, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+water+vapor+pressure+on+the+thermal+decomposition+of+2-chloroethylphosphonic+acid.">Effect of water vapor pressure on the thermal decomposition of 2-chloroethylphosphonic acid.</a> Plant Physiol. 63 (3), 474-477 (1979).</li><li>Murashige, T., Skoog, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+revised+medium+for+rapid+growth+and+bio+assays+with+tobacco+tissue+cultures.">A revised medium for rapid growth and bio assays with tobacco tissue cultures.</a> Physiol. Plant. 15 (3), 473-497 (1962).</li><li>Schramm, M., Hestrin, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Factors+affecting+production+of+cellulose+at+the+air/liquid+interface+of+a+culture+of+Acetobacter+xylinum.">Factors affecting production of cellulose at the air/liquid interface of a culture of Acetobacter xylinum.</a> J. Gen. Microbiol. 11 (1), 123-129 (1954).</li><li>Schneider, C. A., Rasband, W. S., Eliceiri, K. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NIH+Image+to+ImageJ:+25+years+of+image+analysis.">NIH Image to ImageJ: 25 years of image analysis.</a> Nat. Methods. 9 (7), 671-675 (2012).</li><li>Ciolacu, D., Ciolacu, F., Popa, V. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amorphous+cellulose-structure+and+characterization.">Amorphous cellulose-structure and characterization.</a> Cellul. Chem. Technol. 45 (1), 13-21 (2011).</li></ol>

The authors have nothing to disclose.

השיטות שתוארו כאן מתארות את בייצור באתרו של אתילן CEPA לחקר תגובת אתילן חיידקים באמצעות האורגניזם המודל, ק xylinus. שיטה זו מאוד שימושי כמו אתילן יכול להיות מיוצר על ידי השלמת כל בתווך מימי כי יש pH גדול מ 3.5 10,11 עם CEPA מבטל את הצורך גז אתילן טהור או ציוד מעבדה מ?...

האתילן אולפינים (C 2 H 4) התגלה לראשונה כהורמון צמח בשנת 1901 כאשר נצפתה כי השתילים אפונה, שגודלו במעבדה כי השתמשו במנורות גז פחם, הציג מורפולוגיה לא תקינה אשר נובעת (hypocotyls) היו קצרים, עבה והתכופף הצידה לעומת שתילי אפונה נורמלים; פנוטיפ מאוחר יותר כינה את 1,2 בתגובה המשולש. מחקרים מאוחרים יותר הראו כי אתילן הוא phytohormone חיוני המווסת תהליכים התפתחותיים רבים כגון צמיחה, תגובת הלחץ, הבשלת הפרי והזדקנות 3. ארבידופסיס thaliana, אורגניזם מודל למחקר בביולוגיה צמח, נחקרה גם לגבי תגובתה אתילן. מוטנטים בתגובת אתילן כמה בודדו על ידי ניצול פנוטיפ בתגובה המשולש שנצפה א כהה המבוגר שתילי thaliana בנוכחות אתילן 1,4,5. מבשר biosynthetic לייצור אתילן בצמחים הוא 1-אחומצת קרבוקסילית minocyclopropane (ACC) 6 והוא נפוץ במהלך assay בתגובה המשולש להגדיל ייצור אתילן אנדוגני שמוביל 1,4,5 פנוטיפ בתגובה המשולש. למרות התגובה אתילן הוא למד נרחב בצמחים, ההשפעה של אתילן אקסוגניים על חיידקים אילתר בהרבה למרות מקירבת חיידקים עם צמחים. מחקר אחד דיווח כי זנים מסוימים Pseudomonas יכולים לשרוד באמצעות אתילן כמקור בלעדי של פחמן ואנרגיה 7. עם זאת, רק שני מחקרים הראו כי חיידקים להגיב אתילן. המחקר הראשון הראה כי זנים של Pseudomonas aeruginosa, פ fluorescens, פ putida, ופ &#39; syringae היו chemotactic כלפי אתילן באמצעות assay התקע agarose שבו agarose מותכת עורבב עם חיץ chemotaxis equilibrated בגז אתילן טהור 8. עם זאת, למיטב ידיעתנו, לא חל Furthדוחות אה באמצעות גז אתילן טהור לאפיין בתגובת אתילן חיידקים, ככל הנראה בשל המתקשים להתמודד עם גזים במעבדה ללא ציוד מיוחד. הדו&quot;ח השני של תגובת אתילן חיידקים הראה כי גדל אתילן ייצור תאי חיידקי ביטוי גנים מושפע חיידק הפרות קשורים, Komagataeibacter (לשעבר Gluconacetobacter) xylinus 9. במקרה זה, במתחם שחרור אתילן, חומצה 2-chloroethylphosphonic (CEPA) שימש ליצירת אתילן באתרם בתוך המדיום התפתחות חיידקים, תוך עקיפת הצורך גז אתילן טהור או ציוד מיוחד. CEPA מייצרת אתילן ביחס של 1: 1 יחס טוחן מעל pH 3.5 10,11 באמצעות תגובת בסיס-זרז, מסדר הראשון 12 - 14. השפלתו של CEPA מתואם חיובית עם pH וטמפרטורה 13,14 ותוצאות בייצור אתילפנטן, כלוריד ופוספט. CEPA מספקת לחוקרים המעוניינים ללמוד תגובות חיידקים אתילן עם אלטרנטיבה נוחה אתילן גזים. המטרה הכללית של הפרוטוקולים הבאים היא לספק שיטה פשוטה ויעילה ללמוד בתגובה אתילן בקטריאלי כולל אימות של רמות רלוונטי מבחינה פיזיולוגית של ייצור אתילן מן הפירוק CEPA במדיום התפתחות חיידקים, ניתוח של pH תרבות על מנת להבטיח CEPA הפירוק אינו פגום במהלך התפתחות חיידקים, והערכת ההשפעה של אתילן על מורפולוגיה פנוטיפ חיידקים. אנו מדגימים פרוטוקולים אלה באמצעות ק xylinus, לעומת זאת, יכולים להיות מותאם הפרוטוקולים הללו ללמוד בתגובה אתילן בחיידקים אחרים על ידי שימוש במדיום הגידול המתאים פנוטיפ המנתח.

<table><tbody><tr><td>1-aminocyclopropane carboxylic acid (ACC)</td><td>Sigma</td><td>A3903</td><td>Biosynthetic precursor of ethylene in plants</td></tr><tr><td>4-sector Petri dish</td><td>Phoenix Biomedical</td><td>CA73370-022</td><td>For testing triple response</td></tr><tr><td>Agar</td><td>BioShop</td><td>AGR001.1</td><td>To solidify medium</td></tr><tr><td>Canon Rebel T1i DLSR camera</td><td>Canon</td><td>3818B004</td><td>For pictures of pellicles</td></tr><tr><td>Cellulase from Trichoderma reesei ATCC 26921&amp;nbsp;</td><td>Sigma</td><td>C2730</td><td>Aqueous solution</td></tr><tr><td>Citric acid</td><td>BioShop</td><td>CIT002.500</td><td>For SH medium</td></tr><tr><td>Commercial bleach</td><td>Life Brand</td><td>57800861874</td><td>Bleach for seed sterilization</td></tr><tr><td>Concentrated HCl</td><td>BioShop</td><td>HCL666.500</td><td>Hydrochloric acid for pH adjustment</td></tr><tr><td>Digital USB microscope</td><td>Plugable</td><td>N/A</td><td>For pictures of colonies</td></tr><tr><td>Ethephon (&amp;ge;96%; 2-chloroethylphosphonic acid)</td><td>Sigma</td><td>C0143</td><td>Ethylene-releasing compound</td></tr><tr><td>Glucose</td><td>BioBasic</td><td>GB0219</td><td>For SH medium</td></tr><tr><td>Komagataeibacter xylinus ATCC 53582</td><td>ATCC</td><td>53582</td><td>Bacterial cellulose-producing alphaproteobacterium</td></tr><tr><td>Microcentrifuge tube</td><td>LifeGene</td><td>LMCT1.7B</td><td>1.7 ml microcentrifuge tube</td></tr><tr><td>Murashige and Skoog (MS) basal medium&amp;nbsp;</td><td>Sigma</td><td>M5519</td><td>Arabidopsis thaliana growth medium</td></tr><tr><td>Na&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt;&amp;middot;7H&lt;sub&gt;2&lt;/sub&gt;O&amp;nbsp;</td><td>BioShop</td><td>SPD579.500</td><td>Sodium phosphate, dibasic heptahydrate for SH medium</td></tr><tr><td>NaCl</td><td>BioBasic</td><td>SOD001.1</td><td>Sodium chloride for saline and control solution</td></tr><tr><td>NaH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;&amp;middot;H&lt;sub&gt;2&lt;/sub&gt;O&amp;nbsp;</td><td>BioShop</td><td>SPM306.500</td><td>Sodium phosphate, monobasic monohydrate for control solution</td></tr><tr><td>NaOH</td><td>BioShop</td><td>SHY700.500</td><td>Sodium hydroxide for pH adjustment</td></tr><tr><td>Paraffin film</td><td>Parafilm</td><td>PM996</td><td>For sealing plates and flasks</td></tr><tr><td>Peptone (bacteriological)</td><td>BioShop</td><td>PEP403.1</td><td>For SH medium</td></tr><tr><td>Petroff-Hausser counting chamber</td><td>Hausser scientific</td><td>3900</td><td>Bacterial cell counting chamber</td></tr><tr><td>Polyethersulfone sterilization filter 0.2 &amp;micro;m</td><td>VWR</td><td>28145-501</td><td>For sterilizing cellulase</td></tr><tr><td>Sucrose</td><td>BioShop</td><td>SUC600.1</td><td>Sucrose for MS medium</td></tr><tr><td>Yeast extract</td><td>BioBasic</td><td>G0961</td><td>For SH medium</td></tr></tbody></table>

utilizing the ethylene-releasing compound, 2-chloroethylphosphonic acid, as a tool to study ethylene response in bacteria

Ethylene (C2H4) is a gaseous phytohormone that is involved in numerous aspects of plant development, playing a dominant role in senescence and fruit ripening. Exogenous ethylene applied during early plant development triggers the triple response phenotype; a shorter and thicker hypocotyl with an exaggerated apical hook. Despite the intimate relationship between plants and bacteria, the effect of exogenous ethylene on bacteria has been greatly overlooked. This is partly due to the difficulty of controlling gaseous ethylene within the laboratory without specialized equipment. 2-Chloroethylphosphonic acid (CEPA) is a compound that decomposes into ethylene, chlorine, and phosphate in a 1:1:1:1 molar ratio when dissolved in an aqueous medium of pH 3.5 or greater. Here we describe the use of CEPA to produce in situ ethylene for the investigation of ethylene response in bacteria using the fruit-associated, cellulose-producing bacterium Komagataeibacter xylinus as a model organism. The protocols described herein include both the verification of ethylene production from CEPA via the Arabidopsis thaliana triple response assay and the effects of exogenous ethylene on K. xylinus cellulose production, pellicle properties and colonial morphology. These protocols can be adapted to examine the effect of ethylene on other microbes using appropriate growth media and phenotype analyses. The use of CEPA provides researchers with a simple and efficient alternative to pure ethylene gas for the routine determination of bacterial ethylene response.

התקנת צלחת סכמטי עבור אימות שחרור אתילן CEPA במדיום SH (pH 7) על ידי assay בתגובה המשולש מוצגת באיור 1 א - ג. זרם-תרשים המתאר את הפרוטוקול הקרומי מוצג באיור 2. Dark-מבוגר א שתילי thaliana להפגין את הפנוטיפ בתגובה המשולשת (קצר ורחב...

Watch this Scientific Journal Video about Utilizing the Ethylene-releasing Compound, 2-Chloroethylphosphonic Acid, as a Tool to Study Ethylene Response in Bacteria at JoVE.com

Utilizing the Ethylene-releasing Compound, 2-Chloroethylphosphonic Acid, as a Tool to Study Ethylene Response in Bacteria

The protocols outlined herein facilitate the convenient investigation of bacterial ethylene responses by utilizing 2-chloroethylphosphonic acid (CEPA). Ethylene is produced in situ through the decomposition of CEPA in an aqueous bacterial growth medium, circumventing the requirement for pure ethylene gas.

ניצול במגרש משחררים אתילן, 2-Chloroethylphosphonic חומצה, ככלי לחקר תגובה אתילן בחיידקים

Ethylene (C2H4) is a gaseous phytohormone that is involved in numerous aspects of plant development, playing a dominant role in senescence and fruit ...

utilizing-ethylene-releasing-compound-2-chloroethylphosphonic-acid-as

Research

JoVE Journal

Biochemistry

7.9K Views.  University of Ontario Institute of Technology. The protocols outlined herein facilitate the convenient investigation of bacterial ethylene responses by utilizing 2-chloroethylphosphonic acid (CEPA). Ethylene is produced in situ through the decomposition of CEPA in an aqueous bacterial growth medium, circumventing the requirement for pure ethylene gas. 

Video: Utilizing the Ethylene-releasing Compound, 2-Chloroethylphosphonic Acid, as a Tool to Study Ethylene Response in Bacteria

Assessing Stomatal Response to Live Bacterial Cells using Whole Leaf Imaging

Stomata are natural openings in the plant epidermis responsible for gas exchange between plant interior and environment. They are formed by a pair of guard cells, which are able to close the stomatal pore in response to a number of external factors including light intensity, carbon dioxide concentration, and relative humidity (RH). The stomatal pore is also the main route for pathogen entry into leaves, a crucial step for disease development. Recent studies have unveiled that closure of the pore is effective in minimizing bacterial disease development in Arabidopsis plants; an integral part of plant innate immunity. Previously, we have used epidermal peels to assess stomatal response to live bacteria (Melotto et al. 2006); however maintaining favorable environmental conditions for both plant epidermal peels and bacterial cells has been challenging. Leaf epidermis can be kept alive and healthy with MES buffer (10 mM KCl, 25 mM MES-KOH, pH 6.15) for electrophysiological experiments of guard cells. However, this buffer is not appropriate for obtaining bacterial suspension. On the other hand, bacterial cells can be kept alive in water which is not proper to maintain epidermal peels for long period of times. When an epidermal peel floats on water, the cells in the peel that are exposed to air dry within 4 hours limiting the timing to conduct the experiment. An ideal method for assessing the effect of a particular stimulus on guard cells should present minimal interference to stomatal physiology and to the natural environment of the plant as much as possible. We, therefore, developed a new method to assess stomatal response to live bacteria in which leaf wounding and manipulation is greatly minimized aiming to provide an easily reproducible and reliable stomatal assay. The protocol is based on staining of intact leaf with propidium iodide (PI), incubation of staining leaf with bacterial suspension, and observation of leaves under laser scanning confocal microscope. Finally, this method allows for the observation of the same live leaf sample over extended periods of time using conditions that closely mimic the natural conditions under which plants are attacked by pathogens.

We have developed a simple and reproducible protocol to access stomatal response to live bacteria. This method minimizes wounding and manipulation of the leaf as compared to the use of epidermal peels reported previously.

הערכת התגובה הפיוניות לחיות תאים חיידקיים באמצעות הדמיה עלה שלמים

Stomata are natural openings in the plant epidermis responsible for gas exchange between plant interior and environment. They are formed by a pair of ...

Immunology and Infection

Functional Characterization of RING-Type E3 Ubiquitin Ligases In Vitro and In Planta

Ubiquitination, as a posttranslational modification of proteins, plays an important regulatory role in homeostasis of eukaryotic cells. The covalent attachment of 76 amino acid ubiquitin modifiers to a target protein, depending on the length and topology of the polyubiquitin chain, can result in different outcomes ranging from protein degradation to changes in the localization and/or activity of modified protein. Three enzymes sequentially catalyze the ubiquitination process: E1 ubiquitin-activating enzyme, E2 ubiquitin-conjugating enzyme, and E3 ubiquitin ligase. E3 ubiquitin ligase determines substrate specificity and, therefore, represents a very interesting study subject. Here we present a comprehensive approach to study the relationship between the enzymatic activity and function of the RING-type E3 ubiquitin ligase. This four-step protocol describes 1) how to generate an E3 ligase deficient mutant through site-directed mutagenesis targeted at the conserved RING domain; 2&#8211;3) how to examine the ubiquitination activity both in vitro and in planta; 4) how to link those biochemical analysis to the biological significance of the tested protein. Generation of an E3 ligase-deficient mutant that still interacts with its substrate but no longer ubiquitinates it for degradation facilitates the testing of enzyme-substrate interactions in vivo. Furthermore, the mutation in the conserved RING domain often confers a dominant negative phenotype that can be utilized in functional knockout studies as an alternative approach to an RNA-interference approach. Our methods were optimized to investigate the biological role of the plant parasitic nematode effector RHA1B, which hijacks the host ubiquitination system in plant cells to promote parasitism. With slight modification of the in vivo expression system, this protocol can be applied to the analysis of any RING-type E3 ligase regardless of its origins.

The goal of this manuscript is to present an outline for the comprehensive biochemical and functional studies of the RING-type E3 ubiquitin ligases. This multistep pipeline, with detailed protocols, validates an enzymatic activity of the tested protein and demonstrates how to link the activity to function.

אפיון פונקציונלי של מסוג הטבעת E3 ליגטיות בתוך מבחנה ובפלאנטה

Ubiquitination, as a posttranslational modification of proteins, plays an important regulatory role in homeostasis of eukaryotic cells. The covalent ...

Bacterial Leaf Infiltration Assay for Fine Characterization of Plant Defense Responses using the Arabidopsis thaliana-Pseudomonas syringae Pathosystem

In the absence of specialized mobile immune cells, plants utilize their localized programmed cell death and Systemic Acquired Resistance to defend themselves against pathogen attack. The contribution of a specific Arabidopsis gene to the overall plant immune response can be specifically and quantitatively assessed by assaying the pathogen growth within the infected tissue. For over three decades, the hemibiotrophic bacterium Pseudomonas syringae pv. maculicola ES4326 (Psm ES4326) has been widely applied as the model pathogen to investigate the molecular mechanisms underlying the Arabidopsis immune response. To deliver pathogens into the leaf tissue, multiple inoculation methods have been established, e.g., syringe infiltration, dip inoculation, spray, vacuum infiltration, and flood inoculation. The following protocol describes an optimized syringe infiltration method to deliver virulent Psm ES4326 into leaves of adult soil-grown Arabidopsis plants and accurately screen for enhanced disease susceptibility (EDS) towards this pathogen. In addition, this protocol can be supplemented with multiple pre-treatments to further dissect specific immune defects within different layers of plant defense, including Salicylic Acid (SA)-Triggered Immunity (STI) and MAMP-Triggered Immunity (MTI).

Bacterial Leaf Infiltration Assay for Fine Characterization of Plant Defense Responses using the Arabidopsis thaliana-Pseudomonas syringae Pathosystem

Quantification of pathogen growth is a powerful tool to characterize various Arabidopsis thaliana (hereafter: Arabidopsis) immune responses. The method described here presents an optimized syringe infiltration assay to quantify the Pseudomonas syringae pv. maculicola ES4326 growth in adult Arabidopsis leaves.

חיידקי עלה הסתננות Assay עבור אפיון פיין של תגובות הצמחים ביטחון באמצעות<em&gt; Thaliana-Pseudomonas ארבידופסיס syringae</em&gt; Pathosystem

In the absence of specialized mobile immune cells, plants utilize their localized programmed cell death and Systemic Acquired Resistance to defend ...

Use of the Soft-agar Overlay Technique to Screen for Bacterially Produced Inhibitory Compounds

The soft-agar overlay technique was originally developed over 70 years ago and has been widely used in several areas of microbiological research, including work with bacteriophages and bacteriocins, proteinaceous antibacterial agents. This approach is relatively inexpensive, with minimal resource requirements. This technique consists of spotting supernatant from a donor strain (potentially harboring a toxic compound(s)) onto a solidified soft agar overlay that is seeded with a bacterial test strain (potentially sensitive to the toxic compound(s)). We utilized this technique to screen a library of Pseudomonas syringae strains for intraspecific killing. By combining this approach with a precipitation step and targeted gene deletions, multiple toxic compounds produced by the same strain can be differentiated. The two antagonistic agents commonly recovered using this technique are bacteriophages and bacteriocins. These two agents can be differentiated using two simple additional tests. Performing a serial dilution on a supernatant containing bacteriophage will result in individual plaques becoming less in number with greater dilution, whereas serial dilution of a supernatant containing bacteriocin will result a clearing zone that becomes uniformly more turbid with greater dilution. Additionally, a bacteriophage will produce a clearing zone when spotted onto a fresh soft agar overlay seeded with the same strain, whereas a bacteriocin will not produce a clearing zone when transferred to a fresh soft agar lawn, owing to the dilution of the bacteriocin.

We describe a simple method for screening bacterial cultures for the production of compounds inhibitory towards other bacteria.

השימוש בטכניקת הכיסוי הרך-אגר למסך תרכובות מעכבות הופקו bacterially

The soft-agar overlay technique was originally developed over 70 years ago and has been widely used in several areas of microbiological research, ...

Detection of Histone Modifications in Plant Leaves

Chromatin structure is important for the regulation of gene expression in eukaryotes. In this process, chromatin remodeling, DNA methylation, and covalent modifications on the amino-terminal tails of histones H3 and H4 play essential roles1-2. H3 and H4 histone modifications include methylation of lysine and arginine, acetylation of lysine, and phosphorylation of serine residues1-2. These modifications are associated either with gene activation, repression, or a primed state of gene that supports more rapid and robust activation of expression after perception of appropriate signals (microbe-associated molecular patterns, light, hormones, etc.)3-7. 
Here, we present a method for the reliable and sensitive detection of specific chromatin modifications on selected plant genes. The technique is based on the crosslinking of (modified) histones and DNA with formaldehyde8,9, extraction and sonication of chromatin, chromatin immunoprecipitation (ChIP) with modification-specific antibodies9,10, de-crosslinking of histone-DNA complexes, and gene-specific real-time quantitative PCR. The approach has proven useful for detecting specific histone modifications associated with C4 photosynthesis in maize5,11 and systemic immunity in Arabidopsis3.

A reliable and useful approach to detect histone modifications on specific plant genes is described. The approach combines chromatin immunoprecipitation (ChIP) and real-time quantitative PCR. It allows detection of histone modifications on specific genes with a role in diverse physiological processes.

זיהוי של שינויים היסטון בעלים הצמח

Chromatin structure is important for the regulation of gene expression in eukaryotes. In this process, chromatin remodeling, DNA methylation, and covalent ...

Biology

Collection and Analysis of Arabidopsis Phloem Exudates Using the EDTA-facilitated Method

The plant phloem is essential for the long-distance transport of (photo-) assimilates as well as of signals conveying biotic or abiotic stress. It contains sugars, amino acids, proteins, RNA, lipids and other metabolites. While there is a large interest in understanding the composition and function of the phloem, the role of many of these molecules and thus, their importance in plant development and stress response has yet to be determined. One barrier to phloem analysis lies in the fact that the phloem seals itself upon wounding. As a result, the number of plants from which phloem sap can be obtained is limited. One method that allows collection of phloem exudates from several plant species without added equipment is the EDTA-facilitated phloem exudate collection described here. While it is easy to use, it does lead to the wounding of cells and care has to be taken to remove contents of damaged cells. In addition, several controls to prove purity of the exudate are necessary. Because it is an exudation rather than a direct collection of the phloem sap (not possible in many species) only relative quantification of its contents can occur. The advantage of this method over others is that it can be used in many herbaceous or woody plant species (Perilla, Arabidopsis, poplar, etc.) and requires minimal equipment and training. It leads to reasonably large amounts of exudates that can be used for subsequent analysis of proteins, sugars, lipids, RNA, viruses and metabolites. It is simple enough that it can be used in both a research as well as in a teaching laboratory.

Collection and Analysis of Arabidopsis Phloem Exudates Using the EDTA-facilitated Method

Knowledge of the composition of the phloem sap as well as the mechanism of its loading and long-distance transport is essential for the understanding of long-distance signaling in plant development and stress/pathogen response and of assimilate transport. This manuscript describes the collection of phloem exudates using the EDTA-facilitated method.

איסוף וניתוח של<em&gt; ארבידופסיס</em&gt; השיפה exudates שימוש בשיטת EDTA-הקלה

The plant phloem is essential for the long-distance transport of (photo-) assimilates as well as of signals conveying biotic or abiotic stress. It ...

מדידת תגובה סטומטית אוטומטית לפלישת חיידקים בארבידופסיס

Direct Observation and Automated Measurement of Stomatal Responses to Pseudomonas syringae pv. tomato DC3000 in Arabidopsis thaliana

Stomata are microscopic pores found in the plant leaf epidermis. Regulation of stomatal aperture is pivotal not only for balancing carbon dioxide uptake for photosynthesis and transpirational water loss but also for restricting bacterial invasion. While plants close stomata upon recognition of microbes, pathogenic bacteria, such as Pseudomonas syringae pv. tomato DC3000 (Pto), reopen the closed stomata to gain access into the leaf interior. In conventional assays for assessing stomatal responses to bacterial invasion, leaf epidermal peels, leaf discs, or detached leaves are floated on bacterial suspension, and then stomata are observed under a microscope followed by manual measurement of stomatal aperture. However, these assays are cumbersome and may not reflect stomatal responses to natural bacterial invasion in a leaf attached to the plant. Recently, a portable imaging device was developed that can observe stomata by pinching a leaf without detaching it from the plant, together with a deep learning-based image analysis pipeline designed to automatically measure stomatal aperture from leaf images captured by the device. Here, building on these technical advances, a new method to assess stomatal responses to bacterial invasion in Arabidopsis thaliana is introduced. This method consists of three simple steps: spray inoculation of Pto mimicking natural infection processes, direct observation of stomata on a leaf of the Pto-inoculated plant using the portable imaging device, and automated measurement of stomatal aperture by the image analysis pipeline. This method was successfully used to demonstrate stomatal closure and reopening during Pto invasion under conditions that closely mimic the natural plant-bacteria interaction.

מחבר זרקור: קידום מחקר סטומטלי עם מדידת צמצם אוטומטית

Here, we present a simple method for direct observation and automated measurement of stomatal responses to bacterial invasion in Arabidopsis thaliana. This method leverages a portable stomatal imaging device, together with an image analysis pipeline designed for leaf images captured by the device.

תצפית ישירה ומדידה אוטומטית של תגובות סטומאטליות למזרקי Pseudomonas PV . עגבניה DC3000 ב Arabidopsis thaliana

Stomata are microscopic pores found in the plant leaf epidermis. Regulation of stomatal aperture is pivotal not only for balancing carbon dioxide uptake ...

Plant-Microbe Interaction: Transcriptional Response of Bacillus Mycoides to Potato Root Exudates

Beneficial plant-associated bacteria play an important role in promoting growth and preventing disease in plants. The application of plant growth-promoting rhizobacteria (PGPR) as biofertilizers or biocontrol agents has become an effective alternative to the use of conventional fertilizers and can increase crop productivity at low cost. Plant-microbe interactions depend upon host plant-secreted signals and a reaction hereon by their associated bacteria. However, the molecular mechanisms of how beneficial bacteria respond to their associated plant-derived signals are not fully understood. Assessing the transcriptomic response of bacteria to root exudates is a powerful approach to determine the bacterial gene expression and regulation under rhizospheric conditions. Such knowledge is necessary to understand the underlying mechanisms involved in plant-microbe interactions. This paper describes a detailed protocol to study the transcriptomic response of B. mycoides EC18, a strain isolated from the potato endosphere, to potato root exudates. With the help of recent high-throughput sequencing technology, this protocol can be performed in several weeks and produce massive datasets. First, we collect the root exudates under sterile conditions, after which they are added to B. mycoides cultures. The RNA from these cultures is isolated using a phenol/chloroform method combined with a commercial kit and subjected to quality control by an automated electrophoresis instrument. After sequencing, data analysis is performed with the web-based T-REx pipeline and a group of differentially expressed genes is identified. This method is a useful tool to facilitate new discoveries on the bacterial genes involved in plant-microbe interactions.

Plant-Microbe Interaction: Transcriptional Response of Bacillus Mycoides to Potato Root Exudates

The goal of the protocol presented here is to study the transcriptomic response of endosphere-isolated Bacillus mycoides to potato root exudates. This method facilitates the identification of important bacterial genes involved in plant-microbe interactions and is in principle applicable to other endophytes and plants, with minor adjustments.

ניצול במגרש משחררים אתילן, 2-Chloroethylphosphonic חומצה, ככלי לחקר תגובה אתילן בחיידקים

Summary

Explore More Videos

Chapters in this video

הערכת התגובה הפיוניות לחיות תאים חיידקיים באמצעות הדמיה עלה שלמים

אפיון פונקציונלי של מסוג הטבעת E3 ליגטיות בתוך מבחנה ובפלאנטה

חיידקי עלה הסתננות Assay עבור אפיון פיין של תגובות הצמחים ביטחון באמצעות

השימוש בטכניקת הכיסוי הרך-אגר למסך תרכובות מעכבות הופקו bacterially

זיהוי של שינויים היסטון בעלים הצמח

איסוף וניתוח של

תצפית ישירה ומדידה אוטומטית של תגובות סטומאטליות למזרקי Pseudomonas PV . עגבניה DC3000 ב Arabidopsis thaliana

תצפית ישירה ומדידה אוטומטית של תגובות סטומאטליות למזרקי Pseudomonas PV . עגבניה DC3000 ב Arabidopsis thaliana

תצפית ישירה ומדידה אוטומטית של תגובות סטומאטליות למזרקי Pseudomonas PV . עגבניה DC3000 ב Arabidopsis thaliana

צמח-חיידק האינטראקציה: תעתיק בתגובה של Bacillus Mycoides תפוחי אדמה שחורה Exudates