Biolistic transformation Flashcards
Describe briefly particle bombardment
The delivery of heavy metal particles into plant cells
The particles carry DNA/RNA and are accelerated towards the target by an explosive force
The genetic material is delivered to the nucleus through breaches in the cell wall
What are the 7 steps in particle bombardment?
- Pressurised helium tank that is under vacuum
- Rupture disc is placed near the inlet of He gas
- Macrocarrier disc loaded with gold/tungsten particles and DNA is placed below the rupture disc
- Wire mesh stopping screen is placed under the macrocarrier
- Rupture disc stops to /he from entering thus pressure builds up
- Rupture disc opens when the maximum pressure has been reached and He enters the chamber and slams the macrocarrier
- Macrocarrier displaces and hit the stopping screen and particles displace towards tissue
What are the advantages of particle bombardment?
Simple
Broad application range
Multiple genes can be introduced simultaneously (14 is highest)
No plasmid needed
What is plastid biolistic transformation?
A leaf is bombarded with DNA coated tungsten/gold
When DNA is delivered to one chloroplast, integration of the transgene occurs, generating a heteroplastomic cell in which a small number of plastid genomes are transgenic (open circles)
Why genetically engineer chloroplasts?
Natural containment High expression level No gene silencing Multigene Maternal inheritance
What are some problems with plastid transformation?
Lack of suitable vectors
May be genetically unstable
What is somaclonal variation?
The variation seen in plants that have been produced by plant tissue culture
What are some genetic effects of somaclonal variation?
Changes in chromosome number
Changes in chromosome structure
Changes in DNA sequences
What are some epigenetic effects of somaclonal variation?
Gene amplification
Gene methylation
