PowerPoint Presentation

Julian Avila 5/20/2014PLANT PATHOGEN INTERACTIONSIN TODAYS LECTURE:A few types of plant pathogensINNATE IMMUNITYPlant's tools for preventing diseaseMelotto et al., Stomata in PTI.Plant diseasePseudomonas as a model for studying plant-pathogen interactions

Why should we care?

Liz West

Fire Blight - http://www.caf.wvu.edu/kearneysville/disease_descriptions/omblight.html - Erwinia amylovora (Gram - )Apple scab - http://www.apsnet.org/publications/imageresources/Pages/Volume87-7-3.aspx - Venturia inaequalis (Ascomycete)Powdery Mildew - http://postharvest.tfrec.wsu.edu/marketdiseases/powdery.html - Podosphaera leucotrichaRaspberry Tobacco streak - https://www.flickr.com/photos/calliope/4731685098/ - VirusRaspberry Bushy Dwarf Virus (RBDV)- Center - http://berrygrape.org/raspberry-bushy-dwarf-virus-rbdv-found-in-marion/Potato with root knot nematode - http://www.science.oregonstate.edu/bpp/Plant_Clinic/images/potato_meloidogyne.htm0 Meloidogynesp.)Swiss needle cast - http://ornamentaldiagnostics.blogspot.com/2010/04/disease-hotline-issue-3.html - Phaeocryptopus gaeumannii

2THE STRATEGIES PATHOGENS USED ARE DIVERSEBiotrophicHOST SPECIALIZEDNecrotrophicHOST SPECIALIZEDNON-HOST SPECIALIZEDHemitrophic

Phytophtora infestansPowdery mildew on cabbage(Oomycetes)Botrytis cinereaPseudomonas syringae

http://www.apsnet.org/publications/imageresources/Pages/default.aspxPlant pathogens in the news

Liz West

Fire Blight - http://www.caf.wvu.edu/kearneysville/disease_descriptions/omblight.htmlApple scab - http://www.apsnet.org/publications/imageresources/Pages/Volume87-7-3.aspxRaspberry Tobacco streak - https://www.flickr.com/photos/calliope/4731685098/Raspberry Bushy Dwarf Virus (RBDV)- Center - http://berrygrape.org/raspberry-bushy-dwarf-virus-rbdv-found-in-marion/Potato (Solanum tuberosum) with root knot nematode (Meloidogynesp.) - http://www.science.oregonstate.edu/bpp/Plant_Clinic/images/potato_meloidogyne.htmSwiss needle cast - http://ornamentaldiagnostics.blogspot.com/2010/04/disease-hotline-issue-3.html

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LIMEPOCALYPSE

Retrieved on 5/13/14

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

Huanglongbing onmandarin orangesInsect transmittedBacterial (Candidatus liberibacter)Phloem restrictedOriginally found in AsiaAppeared in Florida in 1998Reported in Mexico in 2009No treatment or resistant variety knownCITRUS GREENING DISEASE (Huanglongbing)PATHOGENSPLANTSUsing 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 exampleThe pathogen Candidatus liberibacter enters plant tissue in wounds caused by plant-feeding insects.Plants release chemical compounds to warn other plants of insect attacks.

vs.PATHOGENSPLANTSvs.COLONIZE ENTRY MECHANISMS

THRIVE REPLICATEDIVIDEREPRODUCEcell-wall-degrading enzymes, exopolysaccharides, siderophores and adhesins

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DETECTION SYSTEMSCHEMICAL WEAPONSPHYSICAL BARRIERSSABOTEURSDECOYS

Pseudomonas syringae as pathogenesis/resistance modelBacterial SpeckDiseaseCaused by Pseudomonas syringae pathovar tomato(Pst)

by Tom Zitter and R. ThilmonyPseudomonas syringae as a modelConveniently, Pst can also infect Arabidopsis thaliana

PNAS 102(31):1106411069Conveniently, different P. syringae strains have been sequencedP. syringae pv. syringae B728a vs. P. syringae pv. Tomato DC300Pst colonization mechanism

INFECTION OF SUSCEPTIBLE PLANTSPst can survive on the leaf surface.Pst enters the apoplast through stomata or wounds

Melotto et al. 2006EPIPHYTIC GROWTHAPOPLASTIC GROWTHSTOMATA

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 PstDC3000 (gray bars). In this and all other figures, results are shown as mean (n = 60 stomata) SEM unless otherwise noted.Melotto et al. 2006Colonization

PLANT RESPONDS TO THIS NON-SPECIFICALLYPst USED A WEAPON2h4hMelotto et al. 2006

Stomatal aperture in epidermal peels of Col-0 plants exposed to water (white bars) orE. coliO157:H7 (gray bars).Colonization

Pst DC3000E. coli O157:H7Plants can sense a human pathogen!But.. stomatal re-opening is specific to the plant pathogen Pst

17What 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 mM flg22 or 100 ng/ml LPS)THIS FIGRE GIVES US INFORMATION ON:EXAMPLES OF WHAT PLANTS SENSEA GLIMPSE INTO THE MECHANISM BY WHICH STOMATA CLOSE IN RESPONSE TO SENSING BACTERIA

FLAGELLINELONGATION FACTOR TuPEPTIDOGLICANLIPOPOLYSACCHARIDECHITINXYLANASEHEPTAGLUCAN (HG)

PATHOGEN/MICROBIAL ASSOCIATED MOLECULAR PATTERNS (PAMPs/MAMPS)

*flg22 is a short immunogenic fragment of flagellin

FLAGELLINQRLSTGSRINSAKDDAAGLQIAFlg22:The Plant Journal (1999)18(3),265276PAMP TRIGGERED (INNATE) IMMUNITY - PTIThe perception of PAMPS triggers a set of defense responses. In the next couple of slides we will explore some of them.

Transient ROS production in response to livePst DC3000 wild type Arabidopsis Col-0. A: Time-course of ROS production in response toPtoDC3000 (n=48/treatment). RLU, Relative Light Units

PAMP TRIGGERED (INNATE) IMMUNITY - PTIPstPst

How does this experiment work?

WHY WOULD PLANTS PRODUCE H2O2?23

REACTIVE OXYGEN SPECIES

CHEMICAL WEAPONSPTISTOMATAL CLOSUREREACTIVE OXYGEN SPECIES

flg22 activates MPKs. MAPK activation with or without 100nM flg22 for 10min (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.)Myelin basic protein (an MAPK substrate) Mitogen Activated Protein KinasePAMP TRIGGERED (INNATE) IMMUNITY - PTIMAPKs

One of the most ubiquitous types of post-translational modificationsSTRUCTUREACTIVITYLOCALIZATIONPROTEIN STABILITYINTERACTION PARTNERSPROTEIN PHOSPHORYLATION

KINASE ASSAYMAPKsMAPK9

TAGPlant protoplastsPlasmidTAG-binding resinMAPKMAPKMAPKMAPKMBP-32P- ATPPThe amount of incorporated phosphate shows the catalytic activity of the kinase.

Which MAPK is activated by flg22?(32P incorporated)

MAPKKKsMAPKKsMAPKs601020RESPONSEStimuliMitogenActivatedProteinKinaseCascadeMEK1?MAPKK4/MAPKK5MAPK3/MAPK6

PAMP TRIGGERED (INNATE) IMMUNITY - PTIMAPKs

ResponsePPPPPP(32P incorporated)Stimulus 1Stimulus BRESPONSEARESPONSEBhttp://molbio.mgh.harvard.edu/sheenweb/mapk_project.html29PTISTOMATAL CLOSUREREACTIVE OXYGEN SPECIESMAPK CASCADE ACTIVATIONCALLOSE DEPOSITIONCa++ InfluxPst STRIKES BACK

CHEMICAL WEAPONSCORONATINE

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.

COR+ COR- TTSS-

We will talk about this next week

Control of PAMP-triggered stomatal responses

Salicylate HydroxylasePTISTOMATAL CLOSUREREACTIVE OXYGEN SPECIESMAPK CASCADE ACTIVATIONCALLOSE DEPOSITIONCa++ INFLUXSALICYLIC ACID

PAMP TRIGGERED (INNATE) IMMUNITY - PTISYSTEMIC ACQUIRED RESISTANCEFigure 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

PAMP TRIGGERED (INNATE) IMMUNITY - PTISYSTEMIC ACQUIRED RESISTANCEsource: Taiz L., Zeiger E., 2010

Willow tree barkGenus: SalixAcetylsalicylic acid

BAYER35

How does it work?

CHEMICAL WEAPONSCORONATINETypically, 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.Pst needs to shut this down!BiotrophicNecrotrophic

Jasmonate can induce senescence, leaf absicion and inhibit germination. Loss of chlorophyll degradation of chloroplast proteinsJasmonate induces fruit ripening likely through Ethylene36How does it work?

CHEMICAL WEAPONSCORONATINE:A JASMONATEANALOGUE?

Nature Chemical Biology5, 273 - 274 (2009)

SABOTEURSPstPlant..Jasmonates can 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 cellsLeukemia2002;16:60816How does it work?

CHEMICAL WEAPONSCORONATINE:A JASMONATEANALOGUE

Remember Brittneys AUX/IAA story?

How does it work?CORONATINE:A JASMONATEANALOGUERemember Brittneys AUX/IAA story?

COR

Robert NordsieckKstner et al., ICommunicative & Integrative Biology 2014 7(1): e28728.

Questions?!Next week: Effector Triggered Immunity