Agrobacterium

Question 1

Argobacterium Tumefaciens

Answer 1

Crown-Gall disease

Crown gall represents an uncontrolled tumor-like growth of undifferentiated plant tissue

Question 2

Argobacterium rhizogenes

Answer 2

Hairy root disease

uncontrolled root growth emanating from the stem

Question 3

Wound cycle- tumorgenesis

Answer 3

Infect Wound site by argobacterium
attachment if agrobacterium cells to plant cells-> requires Ti plasmid to infect
processing of T-DNA from Ti plasmid
transfer of T-DNA into plant cell by conjugation-> incorporated into genome
Integration of T-DNA into plant genome->T-DNA causes tumor
Tumorgenesis

Question 4

The Ti plasmid composition

Answer 4

argobacterium tells plant to make opine, but it can degrade opine as a food source
onc and ops genes are transmissibility genes
onc- oncogenes
ops- opine synthesis
vir genes (ABGCDE) encode virulence factors
opine degradation genes

Question 5

T-DNA transfer induction

Answer 5

plant is wounded-> secretes sugars and aromatic compounds to attract agrobacterium to the wound
phenol compounds bind to vir A signal receptor
-responds to phenols
- phosphorylated transfer P to Vir-G
vir-G nicks t-DNA at transmissibility site
S_S DNA encoded by VirE
-SSDNA translocated DNA
DNA goes to nucleus, is integrated into genome randomly

Question 6

The argobacterium genome composition

Answer 6

Most bacteria have on genome, agrobacterium have two
circular and linear chromosome + Ti plasmid and conjugal transfer
has transmissibility factos, antibiotic resistance genes, etc.

Question 7

GMO

Answer 7

Plasmid has antibiotic resistance genes, Origin of recombinant sites
Plasmids transferred by conjugation, D-Ti combined w recombinant plasmid
D-Ti with vir genes and recombinant plasmid are transferred to plant cells and integrated into the nucleus
regenerate transgenic plant cells