Bacterial virulence and Plant disease
-
Upload
saif-ullah -
Category
Science
-
view
82 -
download
5
Transcript of Bacterial virulence and Plant disease
![Page 1: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/1.jpg)
Saifullah11-ARID-489
M.Sc Hons Plant pathology
Bacterial virulence and Plant disease
![Page 2: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/2.jpg)
Definition of VirulenceDifferentiation between Virulence and
PathogenisityVirulent proteinsType three secretion systemHypersensitive responseDefinition of diseaseSymptoms
Contents
![Page 3: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/3.jpg)
The ability of a microorganism to invade and cause injury to the host. It is the relative capacity of a microorganism to overcome the host defense mechanism
Tanada and Kaya (1993)OR
The severity of disease
Barr (1978)
Definition of Virulence
![Page 4: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/4.jpg)
virulence
• Virulence is the measurement of the ability to cause a disease in host
• It describes the quantitative negative effect on host.
Pathogenicity
• Pathogenicity is the ability to cause a disease in host organisms
• The pathogenicity is a qualitative measurement
Differentiation between Virulence and Pathogenisity
![Page 5: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/5.jpg)
Poly saccharides.
Plant cell wall degrading enzymes.
Type three secretion system.
Growth regulators.
Virulent proteins
![Page 6: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/6.jpg)
Many plant pathogens produce large amount of exopolysaccharides.
EPS’s are carbohydrate polymers that are secreted by bacteria and form either a closely attached capsule layer surrounding the bacterial cell.
FunctionsFacilitate absorption of water, minerals and nutrients.Providing protection against abiotic stressesPromoting colonizationContributing to the production of disease.
Poly saccharides
![Page 7: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/7.jpg)
Plant cell walls are composed of several complex carbohydrate polymers, the most abundant of which are cellulose, hemicellulose, and pectin.
Many plant pathogens include a battery of cell wall degrading enzymes in their repertoire of virulence factors.
Pectinases Cellulases Proteases
Plant cell wall degrading enzymes
![Page 8: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/8.jpg)
Plant hormones, which are also often referred to as ‘‘plant growth regulators,’’ are endogenous signaling molecules important for many aspects of plant growth and development.
Growth regulators
Auxin Ethylene CytokininsAbscisic acidGibbberellins
![Page 9: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/9.jpg)
T3SS are complex bacterial structures.
Found in Gram –ive bacteria.
Pilus like structure called Hrp pili.
Type three - secretion system
![Page 10: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/10.jpg)
![Page 11: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/11.jpg)
The hypersensitive response (HR) is a mechanism, used by plants, to prevent the spread of infection by microbial pathogens.
The HR is characterized by the rapid death of cells in the local region surrounding an infection.
The HR serves to restrict the growth and spread of pathogens to other parts of the plant.
Hypersensitive response
![Page 12: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/12.jpg)
A plant disease is any physiological or structural abnormality that is caused by a living organism.
It is a physiological process that affects some or all plant functions.
Disease is a process or a change that occurs over time. It does not occur instantly like injury.
Plant disease
![Page 13: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/13.jpg)
Visible effects of disease on plants are called symptoms.
Any detectable changes in color, shape, and/or functions of the plant in response to a pathogen is symptom.
Symptoms
![Page 14: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/14.jpg)
Bacterial spot of tomato
Mosaic on cucumber.
Anthracnose of mangoGalls produced by root knot nematode
![Page 15: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/15.jpg)
![Page 16: Bacterial virulence and Plant disease](https://reader035.fdocuments.in/reader035/viewer/2022062400/5883fbb01a28ab884b8b4d6f/html5/thumbnails/16.jpg)