Quorum Sensing in Xanthomonas

Narayan Prahlad V7th SemesterMolecular Biology

Contents Introduction Quorum sensing Xanthomonas Quorum sensing in Xanthomonas QS pathway Quorum sensing-Virulence Conclusion References

Introduction

Quorum SensingQuorum sensing (QS)-phenomenon-bacteria communicate among each other in a cell density dependent media to regulate their gene expression by- release of certain molecules.

Signaling molecules-two main chemical categories: N-acyl homoserine lactones (AHLs)- autoinducer-1 (AI-1)-characteristic of Gram-negative

bacteria; autoinducing peptides (AIPs)-Gram-positive bacteria.

Chemically different signaling molecules have also been identified-

A-factor from Streptomyces (γ-butyrolactone), 4-quinolones Pseudomonas Quinolone Signal -PQS fatty acids (Diffusible Signal Factors-DSF).

General mechanism of QS

(Steven T. Rutherford1 and Bonnie L. Bassler-2012)

Xanthomonas Kingdom -Bacteria

Phylum -Proteobacteria

Class -Gammaproteobacteria

Order -Xanthomonadales

Family -Xanthomonadaceae

Genus -Xanthomonas

Size of Genomic DNA - 4.17 Mbp- 5.12 Mbp

Electron Microscopic image of Xanthomonas

X. campestris pv campestris, X. citri.

Citrus cankerBacterial leaf spot

Xanthomonas oryzae. pv. oryzae -Bacterial Blight (BB)

X .oryzae pv oryzicola bacterial leaf streak (BLS).

Electron Microscopic Image of Xoo in Xylem vessel of Rice

QS in XanthomonasQS takes place by production of- Diffusible Signal Factor (DSF).

The perception of these signals can influence different aspects of bacterial behavior like biofilm formation, synthesis of virulence factors etc.

(cis-11-methyl-2-dodecenoic acid)

DSF- Diffusible Signal FactorSynthesised by gene- rpf.

rpfF- DSF Synthase.

Robert P. Ryan and J. Maxwell Dow-2011

DSF Synthase

Ya-Wen He & Lian-Hui Zhang-2008

QS Pathway-Cell Density

Ya-Wen He & Lian-Hui Zhang-2008

QS Pathway-

Daniela Buttner & Ulla Bonas-2009

Quorum Sensing-VirulenceDegree of infection- Virulence

1) Extracellular polysaccharide (EPS)

2) Biofilm

3) Lipopolysacharide

EPS Biofilm

(Rai et.al 2015)

Gram –ve Cell wall

Xcc Xoo

Effect of Fungal Endophytes-Xanthomonas oryzae

Sonika Jha-2014 unpublished

List of Endophytes

Fungus HostA. Alternaria Catheranhus roseusB. Arthirinium Elaeocarpus serratusC. Aspergillus Altingea excelsaD. Bartalinia BT-cottonE. Botrytis Erythroxylon monogynumF. Chaetomium BT-cottonG. Colletrotrichum BT-cottonH. Corynespora Entada rheediI. Curvularia Pedilanthus tithymaloidesJ. Cylindrocladium Piper mullesuaK. Dendryphion Coldenia procumbensL. Drechslera Coldenia procumbensM. Fusarium Sargassum wightiiN. Gilmaniella Datura metalO. Humicola Datura metalP. Lasiodiplodia theobromae Coelogyne sp.(Orchid)Q. Nigrospora Leucas asperaR. Penicillium BT-cottonS. Pestalotiopsis Syzgium cuminiT. Phomopsis NBT-cottonU. Phylosticta Turpinia nepalensisV. Pithomyces Eurya nitidaW. Trichocladium Datura metalX. Trichoderma harzianum Sargassum wightiiY. Xylaria Zizyphyus jujuba

TechniquePrimary culture-Rifampicin, Cyclohexamide (CHM) and Cephalaxin (CPL)

Secondary culture- 0.2% Primary culture

Control- only culture

Methanol control (MC)- culture + methanol

20μl fungal endophytes was added.

Incubated for 44 hours

O.D-600 nm

Effect of Fungal Endophytes- Xanthomonas campestris

Sonika Jha-2014 unpublished

Effect of Fungal Endophytes- Alternaria

Xom/C Xom/MC Xom/20μl Xom/25μl Xom/30μl Xcc/C Xcc/MC Xcc/20μl Xcc/25μl Xcc/30μl0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

Endophyte from Alternaria (Crude Extract)

Strains

O.D

at 6

00 n

m a

fter

24 H

ours

TechniquePrimary culture of Xoo and Xcc-Rifampicin, Cyclohexamide (CHM) and Cephalaxin (CPL)

Secondary culture- 0.2% Primary culture

Control- only culture

Methanol control (MC)- culture + methanol

20,25 and 30μl endophyte from Alternaria was added to both.

Incubated for 24 hours

O.D-600 nm

Conclusion

QS plays an important role in bacteria during pathogenesis.

some marine organisms- Squids.

The light organ is colonized by a large number of Vibrio fischeri - autoinducer accumulates to a threshold concentration, triggering light production.

These examples of cell-cell communication demonstrate what might be called multicellular behavior in that many individual cells communicate and coordinate their activities to act as a unit.

Xanthan- used as a food additive-as a food thickening agent (in salad dressings, for example)

stabilizer (in cosmetic products, for example, to prevent ingredients from separating).

Structure of Xanthan

ReferencesDaniela Buttner & Ulla Bonas (2009); Regulation and secretion of Xanthomonas virulence factors. FEMS Microbiol Rev 34 (2010); 107- 121.

DAVID O. NIÑO-LIU PAMELA C. RONALD AND ADAM J. BOGDANOVE (2006); Xanthomonas oryzae pathovars: model pathogens of a model crop. 2006 BLACKWELL PUBLISHING LTD.303-310.

Robert P. Ryan and J. Maxwell Dow (2011); Communication with a growing family: diffusible signal factor (DSF) signaling in bacteria. Trends in Microbiology March 2011, Vol. 19, No. 3; Cell Press.145-150.

Ya Wen He et.al; Quorum sensing and virulence regulation in Xanthomonas campestris; 2008; Institute of Molecular and Cell Biology, Singapore, Singapore; FEMS Microbiol Rev; 842-854

Steven T. Rutherford1 and Bonnie L. Bassler (2012); Bacterial Quorum Sensing: Its Role in Virulence

and Possibilities for Its Control Cold Spring Harb Perspect Med 2012;2: a012427. Cold Spring Harbor Laboratory Press. 2012; 1-3, 9-11

Robert P. Ryan and J. Maxwell Dow (2011); Communication with a growing family: diffusible signal factor (DSF) signaling in bacteria. Trends in Microbiology March 2011, Vol. 19, No. 3; Cell Press.145-150.

Christopher M.Waters and Bonnie L. Bassler (2005). Quorum Sensing: Cell-to-Cell Communication in Bacteria; Annu. Rev. Cell Dev. Biol. 2005.

Acknowledgements I would like to thank my guide R. Chandrakanth for his guidance.

I would also like to thank our course coordinator Dr. N.S Devaki for providing me this opportunity to present this seminar.

I would whole heartedly thank the members in the lab of Plant-Microbe Interaction, CDFD, Hyderabad.

Thank u all for your patience.

Thank You

Type II and III Secretion Systems6 types of Secretion systems (SS). Type I (T1S)- VI (T6S).

Vary in composition and function.

Not conserved.

T2S and T3S are very important during host-pathogen interaction.

Daniela Buttner & Ulla Bonas-2009T2S and T3S Systems

ControlCultural Methods-

At the nursery stage-

seed disinfection, proper nursery drainage, and removal of diseased plants, weeds and debris.

Prior to transplanting, fields-disinfected by burning rice straw left from the previous season.

Weeds-removed from canals and ridges in order to reduce natural habitats for the pathogen and its dispersal through irrigation water.

Paddy field stage, judicious fertilization and proper plant spacing are the most recommended cultural methods of control.

Chemical Methods-

Bordeaux mixture (hydrated lime and copper sulfate) , several antibiotics, mercuric and copper compounds.

Inefficent- damage rice grains when sprayed.

In temperate regions, probenazole-added to the paddy water before and after transplanting the seedlings-to inhibit bacterial multiplication and prevent or retard the disease.

Other chemicals such as tecloftalam, phenazine oxide and nickel dimethyldithiocarbamate are sprayed directly on plants

However, chemical control of BB in the tropical monsoon climate of Asia is impractical, and no truly effective bactericide is commercially available for disease control.

Biological control-

Pseudomonas fluorescens and P. putida strain V14i (also used in biocontrol of the rice sheath blight pathogen Rhizoctonia solani) significantly suppressed BB severity when sprayed on leaves.

Breeding and deployment of resistant cultivars carrying major resistance (R ) genes-most effective approach to controlling BB.