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Julian Avila 5/20/2014

PLANT PATHOGEN INTERACTIONS. IN TODAYS LECTURE:. Plant disease. A few types of plant pathogens. Pseudomonas as a model for studying plant-pathogen interactions. INNATE IMMUNITY Plant's tools for preventing disease Melotto et al., Stomata in PTI. Julian Avila 5/20/2014.

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Julian Avila 5/20/2014

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  1. PLANT PATHOGEN INTERACTIONS IN TODAYS LECTURE: Plant disease A few types of plant pathogens Pseudomonas as a model for studying plant-pathogen interactions INNATE IMMUNITY Plant's tools for preventing disease Melotto et al., Stomata in PTI. Julian Avila 5/20/2014

  2. Why should we care? Liz West

  3. THE STRATEGIES PATHOGENS USED ARE DIVERSE Powdery mildew on cabbage (Oomycetes) Biotrophic HOST SPECIALIZED Phytophtorainfestans Hemitrophic Pseudomonas syringae Botrytis cinerea Necrotrophic HOST SPECIALIZED NON-HOST SPECIALIZED

  4. Plant pathogens in the news Liz West http://www.apsnet.org/publications/imageresources/Pages/default.aspx

  5. LIMEPOCALYPSE

  6. Retrieved on 5/13/14

  7. SAP http://tech.fortune.cnn.com/2014/05/09/a-big-data-look-at-the-lime-shortage/

  8. CITRUS GREENING DISEASE (Huanglongbing) • Insect transmitted • Bacterial (Candidatusliberibacter) • Phloem restricted • Originally found in Asia • Appeared in Florida in 1998 • Reported in Mexico in 2009 • No treatment or resistant variety known 黃龍病 Huanglongbing on mandarin oranges

  9. PLANTS PATHOGENS vs. Using what you have learned in your lifetime, compile a list of all the strategies you can think of that pathogens and plants have developed to cause and prevent disease respectively. For example The pathogen Candidatusliberibacterenters plant tissue in wounds caused by plant-feeding insects. Plants release chemical compounds to warn other plants of insect attacks.

  10. PLANTS PATHOGENS vs. COLONIZE ENTRY MECHANISMS THRIVE REPLICATE DIVIDE REPRODUCE

  11. PHYSICAL BARRIERS CHEMICAL WEAPONS DECOYS SABOTEURS DETECTION SYSTEMS

  12. Pseudomonas syringae as pathogenesis/resistance model Bacterial Speck Disease Caused by Pseudomonas syringaepathovar tomato (Pst)

  13. Pseudomonas syringae as a model P. syringaepv.syringaeB728a vs. P. syringaepv.Tomato DC300 by Tom Zitter and R. Thilmony PNAS 102(31):11064–11069 Conveniently, different P. syringaestrainshave been sequenced Conveniently, Pstcan also infect Arabidopsis thaliana

  14. Pst colonization mechanism EPIPHYTIC GROWTH • INFECTION OF SUSCEPTIBLE PLANTS • Pst can survive on the leaf surface. • Pst enters the apoplast through stomata or wounds STOMATA APOPLASTIC GROWTH Melotto et al. 2006

  15. Colonization A) Open (top and middle panels) and closed stomata (bottom panel). (B) Stomatal aperture in intact leaves (left panel) or epidermal peels (right panel) of Col-0 plants exposed to water (white bars) or Pst DC3000 (gray bars). In this and all other figures, results are shown as mean (n = 60 stomata) ± SEM unless otherwise noted. Melotto et al. 2006

  16. Colonization 2h PLANT RESPONDS TO THIS NON-SPECIFICALLY Melotto et al. 2006 Stomatal aperture in epidermal peels of Col-0 plants exposed to water (white bars) or E. coli O157:H7 (gray bars). 4h Pst USED A WEAPON Pst DC3000 E. coli O157:H7

  17. What do plants sense in pathogens? (E) Effect of the Nitric Oxide Synthase (NOS) inhibitor L-NNA (0.2 mM) on stomatal closure when coincubated with PAMPs (5 mMflg22 or 100 ng/ml LPS) • THIS FIGRE GIVES US INFORMATION ON: • EXAMPLES OF WHAT PLANTS SENSE • A GLIMPSE INTO THE MECHANISM BY WHICH STOMATA CLOSE IN RESPONSE TO SENSING BACTERIA

  18. PATHOGEN/MICROBIAL ASSOCIATED MOLECULAR PATTERNS (PAMPs/MAMPS) • FLAGELLIN • ELONGATION FACTOR Tu • PEPTIDOGLICAN • LIPOPOLYSACCHARIDE • CHITIN • XYLANASE • HEPTAGLUCAN (HG) *flg22 is a short immunogenic fragment of flagellin

  19. FLAGELLIN Flg22: QRLSTGSRINSAKDDAAGLQIA The Plant Journal (1999) 18(3), 265–276

  20. PAMP TRIGGERED (INNATE) IMMUNITY - PTI The perception of PAMPS triggers a set of defense responses. In the next couple of slides we will explore some of them.

  21. PAMP TRIGGERED (INNATE) IMMUNITY - PTI Pst Pst Transient ROS production in response to live PstDC3000 wild type Arabidopsis Col-0. A: Time-course of ROS production in response to Pto DC3000 (n = 48/treatment).  RLU, Relative Light Units

  22. How does this experiment work? WHY WOULD PLANTS PRODUCE H2O2?

  23. REACTIVE OXYGEN SPECIES CHEMICAL WEAPONS

  24. PTI • STOMATAL CLOSURE • REACTIVE OXYGEN SPECIES

  25. MAPKs PAMP TRIGGERED (INNATE) IMMUNITY - PTI Mitogen Activated Protein Kinase Myelin basic protein (an MAPK substrate) flg22 activates MPKs. MAPK activation with or without 100 nM flg22 for 10 min (top) and expression of each MAPK are shown (bottom). (Tagged kinases were immunoprecipitated from lysates of transfected protoplasts with the corresponding antibody and analysed with a known substrate as indicated.)

  26. PROTEIN PHOSPHORYLATION STRUCTURE INTERACTION PARTNERS ACTIVITY PROTEIN STABILITY LOCALIZATION One of the most ubiquitous types of post-translational modifications

  27. MAPKs KINASE ASSAY P MAPK9 TAG Which MAPK is activated by flg22? Plasmid (32P incorporated) Plant protoplasts γ-32P- ATP MAPK MAPK MAPK MAPK The amount of incorporated phosphate shows the catalytic activity of the kinase. MBP TAG-binding resin

  28. MAPKs PAMP TRIGGERED (INNATE) IMMUNITY - PTI P P P P P P Stimuli Stimulus 1 Stimulus B MEK1? MAPKKKs 60 Mitogen Activated Protein Kinase Cascade MAPKKs MAPKK4/ MAPKK5 10 MAPKs MAPK3/ MAPK6 20 Response RESPONSE RESPONSE A RESPONSE B (32P incorporated)

  29. PTI • STOMATAL CLOSURE • REACTIVE OXYGEN SPECIES • MAPK CASCADE ACTIVATION • CALLOSE DEPOSITION • Ca++ Influx

  30. PstSTRIKES BACK CORONATINE COR+ COR- TTSS- We will talk about this next week CHEMICAL WEAPONS A) Col-0 leaves were exposed to water (white bars), Pst DC3000 (wavy bars), or the cor mutant Pst DC3118 (gray bars). Bacterial concentration used was 1 3 108 cfu/ml.

  31. Control of PAMP-triggered stomatal responses Salicylate Hydroxylase

  32. PTI • STOMATAL CLOSURE • REACTIVE OXYGEN SPECIES • MAPK CASCADE ACTIVATION • CALLOSE DEPOSITION • Ca++ INFLUX • SALICYLIC ACID

  33. SYSTEMIC ACQUIRED RESISTANCE PAMP TRIGGERED (INNATE) IMMUNITY - PTI Figure 1. P. syringae-induced resistance to P. syringae. The photograph shows upper leaves of plants inoculated with either water (A) or with P. syringae (4x108 cells/ml) (B) on the lower leaves of the rosette. Two days after infection of the lower leaves, upper leaves were challenged with the same pathogen (107 cells/ml). Leaves were photographed 4 d after challenge. Summermatter, et al., Plant Physiol. (1 995) 108: 1379-1 385

  34. SYSTEMIC ACQUIRED RESISTANCE PAMP TRIGGERED (INNATE) IMMUNITY - PTI Willow tree bark Genus: Salix BAYER source: Taiz L., Zeiger E., 2010 Acetylsalicylic acid

  35. How does it work? CORONATINE Pst needs to shut this down! CHEMICAL WEAPONS Necrotrophic Biotrophic “Typically, the pathogen-induced pathway relies on salicylic acid produced by the plant as a signalling molecule, whereas the herbivory-induced pathway relies on jasmonic acid as the signalling molecule.”

  36. How does it work? CORONATINE: A JASMONATE ANALOGUE? CHEMICAL WEAPONS Plant Pst Nature Chemical Biology5, 273 - 274 (2009)  “..Jasmonatescan suppress the proliferation of human cancer cells and induce their death. Methyl jasmonate induced death in breast and prostate carcinoma cells, as well as in melanoma, lymphoma, and leukemia cells ” Leukemia 2002; 16: 608–16 SABOTEURS

  37. How does it work? CORONATINE: A JASMONATE ANALOGUE CHEMICAL WEAPONS Remember Brittney’s AUX/IAA story?

  38. How does it work? CORONATINE: A JASMONATE ANALOGUE COR Robert Nordsieck Kästner et al., ICommunicative& Integrative Biology 2014 7(1): e28728. Remember Brittney’s AUX/IAA story?

  39. Questions?! Next week: Effector Triggered Immunity

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