Podcast
Questions and Answers
What is a key characteristic of Agrobacterium-induced galls?
What is a key characteristic of Agrobacterium-induced galls?
Which component of the Ti plasmid is crucial for genetic engineering in plants?
Which component of the Ti plasmid is crucial for genetic engineering in plants?
What role does salicylic acid play in plant defense mechanisms?
What role does salicylic acid play in plant defense mechanisms?
Which of the following is the first transgenic plant developed?
Which of the following is the first transgenic plant developed?
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How does the bacterium Bacillus velezensis 9D-6 aid in biocontrol for tomato canker disease?
How does the bacterium Bacillus velezensis 9D-6 aid in biocontrol for tomato canker disease?
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What problem does citrus greening cause in plants?
What problem does citrus greening cause in plants?
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What is the role of Chv genes in Agrobacterium?
What is the role of Chv genes in Agrobacterium?
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What triggers transformation in Agrobacterium-plant co-cultivation?
What triggers transformation in Agrobacterium-plant co-cultivation?
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Which method is used for controlling the citrus greening pathogen?
Which method is used for controlling the citrus greening pathogen?
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What can occur due to overexpression of T-DNA in genetically modified plants?
What can occur due to overexpression of T-DNA in genetically modified plants?
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Study Notes
Bacterial Diseases
- Bacterial plant pathogens include Pseudomonas syringae, Agrobacterium tumefaciens, Xanthomonas oryzae, and Erwinia amylovora
- Some bacteria are avirulent, and virulent
- Most bacteria require persistent presence to cause disease
- Agrobacterium causes crown gall disease, a neoplastic growth
- Agrobacterium transfers DNA into plant cells via a Ti plasmid (tumor-inducing plasmid)
- Ti plasmid contains T-DNA which integrates into the plant's genome
Genetic Engineering of Plants
- Transgenic plants express Bt toxin (insecticide)
- Golden rice is genetically modified to produce beta-carotene
- Some plants are genetically modified to resist disease and increase yields
- Genetically modified plants can increase resistance to disease, but yield can be affected.
- Methods like Agrobacterium-mediated transformation are used to introduce genes into plants
Bacterial Plant Pathogen Mechanisms
- Agrobacterium use a process called transfer DNA (T-DNA) to introduce genes into plants
- Plant cells release a chemical signal (acetosyringone) which attracts the Agrobacterium
- Bacteria genes are transferred to the plant and integrated into the plant's genome
- Some bacteria trigger plant defenses, such as salicylic acid and ethylene, to limit pathogenic effects
- Bacteria utilize quorum sensing to coordinate their behavior and release virulence factors
- Genes for opine synthesis are important for survival/growth of the pathogen in the plant
- Other pathogens may produce chemicals like surfactin that cause disease
Plant-Bacterial Interactions
- Bacteria can attach to plant cells and begin the infection process.
- Plants use various defense mechanisms like salicylic acid to fight off bacteria
- Quorum sensing regulates bacteria behavior once certain high concentrations are reached.
- Plants modify gene expression to counter the bacterial invasion.
Biocontrol
- Isolation of the bacterium
- Purification/preparation of the chemical made the bacteria
- Plate the pathogen in a mix with the chemical to observe effect
Plant Diseases Symptoms and Pathogens
- Citrus greening is caused by Candidatus Liberobacter, which blocks phloem and causes yellowing and death of citrus trees
- Citrus greening is vectored by psyllids.
- Biological and chemical controls are available for controlling pathogens
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Description
Explore the mechanisms of bacterial plant pathogens and the role of genetic engineering in agriculture. This quiz covers key bacteria such as Agrobacterium and their impact on plant health, alongside advances in transgenic plants like Golden rice. Test your knowledge on disease resistance, yield effects, and genetic modification techniques.
