What are the 3 types of gene flow in plants?
- Pollen
- Seeds
- Vegetative growth
Low distance of gene flow risks what?
inbreeding
How is tetraploid tissue formed?
Tetraploid tissue is formed when cells fail to divide after replication in mitosis
Triploids are not uncommon but are generally sterile. True of false?
True
Which of the following is sterile?
Tetraploids,
Pentaploids,
Hexaploids
Pentaploids
From which parent plant, is the chloroplast genome inherited?
Mother
Many plants reproduce asexually. What two ways does this occur? Define them.
Fragmentation: Clonal growth, tillering, suckers
Apomixis: Production of seed identical to mother
Most species out-cross. Define the following:
- Self-incompatibility
- Monoecious
- Dioecious
Self-incompatibility: Mechanisms to prevent selfing
- Monoecious: Separate male and female flowers
- Dioecious: Male & female plants
Briefly describe inbreeding depression
- Self-crossing is much more common in plants than animals
- The reason many plants can inbreed may be due to the relative importance of the gametophyte generation
- The superior performance of an F1 from inbred parents is called HYBRID VIGOUR. It is very important in crop production
Which parasitic plant has been described as the most important biological constraint to crop production in Africa?
Striga
What is complete resistance?
AKA vertical resistance
- Highly specific (race specific)
- Involves evolutionary genetic interaction (arms race) between host and one species of pathogen
QUALITATIVE
What is partial resistance?
- AKA horizontal resistance
- Not specific - confers resistance to a range of pathogens
QUANTITATIVE
Gene-for-Gene theory of Complete Resistance states that if the pathogen has an AVIRULENCE gene and the host a RESISTANCE gene, then there is what?
No infection
According to the Gene-for-Gene theory of Complete Resistance…
The Avirulence gene codes for what?
An Elicitor molecule or protein controlling the synthesis of an elicitor
According to the Gene-for-Gene theory of Complete Resistance…
The Resistance gene codes for what?
A receptor molecule which “recognises” the Elicitor
According to the Gene-for-Gene theory of Complete Resistance…
A plant with the Resistance gene can detect the pathogen with the avirulence gene. Once the pathogen has been detected, what happens?
The plant responds to destroy the pathogen
According to the Gene-for-Gene theory of Complete Resistance…
Both the resistance gene and the avirulence gene are what (dominant/recessive)?
Dominant
What is an elicitor?
A molecule which induces any plant defence response.
It can be a polypeptide coded for by the pathogen avirulence gene, a cell wall breakdown or low-molecular weight metabolites.
Not all elicitors are associated with gene-for-gene interactions
What is SAR?
Systemic Acquired Resistance
- Long-term resistance to a range of pathogens throughout plant caused by inoculation with inducer inoculum
