Bacteria 1 Flashcards
Characteristics of bacteria
Prokaryote Lack well define organelles DNA not organized DNA circular Container plasmid
Facultative parasites
Free living organism that can become parasitic in certain host
Can live as epiphytes, soil inhabitants, soil invaders
Obligate parasites
Cannot live without host
No free living stage
Difficult or impossible to culture
Bacterial DNA
Circular and plasmid
Shape of bacteria (3)
Spiral, sphere, rod
Types of fillamentous plant pathogenic bacteria
Motility Monotrichrous Lophotrichrous Aamphitricrous Peritrichrous
Reproduction of bacteria
Multiply by binary fission(asexual reproduction)
Binary fission
Rapid 20-50min
Produce clone
Environment strongly influence
Ways to introduce genetic variation
1 mutation the selection ( bacteria is a haploid so selection happen quickly)
2lateral ( horizontal ) gene transfer
3 types of Lateral ( horizontal) gene transfer
Conjugation
Transformation
Transduction
Characteristics of each types of lateral( horizontal) gene transfer
Conjugation- sex pilus or conjugation tube to connect two bacteria and transfer plasmid to another.
Transformation- involve uptake of short fragments of naked DNA by naturally transformable bacteria
Transduction- transfer gene by bacteriophage
Symptom - leaf spots and blight
Common symptom
Halo/yellow zone due to t common pseudomonas, xanthamonas
Symptom vascular wilts
Plug xylem elements, and prevent water movement
Clavibacter, xanthomonas, Erwin is
Symptom bacterial soft rot
Affect root tuber due to enzyme
Utilize pectins from plant cell wall
Pectobacterium carotovorum
Symptoms Timers and galls
Growth disorder by hormon
Agrobacterium
How do we identify bacterial plant pathogens
Physical feature
Physiological feature
Genetic
Serological
Physical feature
True bacteria walled prokaryotes, most rod shape, usually flagella.
Mollicutes wall less
Cell wall composition
Peptidogylcan layer
- gram + peptide grylcan is most outside
- gram - peptidegrylcan is middle
Lipo- polysaccharide outer membrane for only gram -
Pigmentation
Xanthomonadins are unique carotenoids like pigment
Physiological Features
Relating to the way in which a living organism function
- Aerobic or anaerobic growth
- Ability to use specific nutritional sources
- Degradation of given substrates
Soft rot releases pectolytic enzyme – can degrade pectate
hypersensitive on tobacco plant
Genetic Features
DNA
compare DNA sequence with BLAST
Serological Features
Agdia Immunostrip
Identifies bacterial structural or secreted antigens
(usually protein based)
Pathovar
~SUBSPECIES! ~Based on Host Species
Race
~Based on host genotype/cultivars ~Due to genetic differences within species
