Plant Biotechnology Notes

Luther Burbank's Work: Created pure white blackberry, involved 65,000 unsuccessful crosses.
Challenge with Tree Crops: Long maturity time can be jeopardized by newly emerging diseases.

Marker-Assisted Selection:
- Identify genetic variants for desired traits (e.g., productivity, disease resistance).
- Use genetic markers to test tissue samples instead of growing seedlings to maturity.
Mutation Breeding:
- Seeds exposed to chemicals/radiation to induce mutations.
- Most mutations are not useful, but some may yield advantageous traits.
Protoplast Fusion:
- Fuses callus cells from different plants allowing hybrid growth.
- Callus develops after wounding; protoplasts are created by dissolving cell walls.
Genetic Engineering of Plants:
- Inserts new genes into plants (transgenic plants).
- Achieves results not possible with conventional methods, e.g., pest resistance.
Agrobacterium tumefaciens:
- Inserts DNA into plant cells via Ti plasmid, modified to include desired genes.
Leaf Fragment Technique:
- Cultures leaf discs with modified Agrobacterium, integrating modified DNA.
Chloroplast Engineering:
- Target chloroplast DNA for gene insertions; many remain active later.

CRISPR-Cas Technology:
- Used to delete specific genes accurately, improving traits (e.g., browning in mushrooms).
Antisense Technology:
- Introduces complementary gene copies to prevent protein translation.
- Example: Flavr Savr tomato prevented browning, extended shelf life.
Gene Stacking:
- Combining multiple inserted genes via hybrid stacking or molecular stacking techniques.