Ti-Ri plasmid ,tumor formation and some DNA transfer methods are described here..

1. St. THOMAS COLLEGE
RUABANDHA
TOPIC :BASIS OF TUMOR FORMATION ,
Ti- Ri PLASMID & DNA TRANSFER.
(PAPER-7 - PLANT BIOTECHNOLOGY)
GUIDED BY : SUBMITTED BY:
Dr. UJJWALA SUPE V. SUKIRTI
M.Sc. II SEMESTER
BIOTECHNOLOGY
YEAR:- 2016-17

2. SYNOPSIS
 INTRODUCTION.
 BASIS OF TUMOR FORMATION.
 AGROBACTERIUM.
 Ti- PLASMID.
 OPINES.
 HOW Ti- PLASMID CAUSE A DISEASE?
 T- DNA.
 Ri – PLASMID.
 HOW Ri – PLASMID CAUSE A DISEASE?
 DNA TRANSFER.
 REFERENCES.

3. INTRODUCTION
• Agrobacterium is a pathogenic bacteria that
causes tumor in plants .
• Ti- plasmid causes crown gall disease in plants.
• Small part of Ti- plasmid (T- DNA) is transferred
into plant genome.
• Ri – plasmid cause hairy root diseases in plants.
• DNA transfer - The foreign DNA transformation of
bacterial cells and its subsequent integration into the
genetic material of host.

4. BASIS OF TUMOR FORMATION
• Agrobacterium tumefaciens causes tumor in
plants i.e. crown gall disease.
• Agrobacterium rhizogenes causes hairy root
disease.
• The tumor formation results from the transfer of
particular set of Ti & Ri – plasmid into plant
chromosome.
• Tumor formation occur by transfer of small
segment of Ti – plasmid. (T- DNA).

5. AGROBACTERIUM
 There are two main species of agrobacterium :-
1. Agrobacterium tumefaciens -
 Infects damaged plant tissue which is induced plant
tumor i.e. crown gall.
 Crown gall occurs when bacterium releases Ti – plasmid
into cytoplasm.
2. Agrobacterium rhizogenes -
 induces hairy root disease.
 Bacterial genes transfer its T- DNA from its Ri- plasmid
into plant through wound.

6. Ti- PLASMID
• Extra chromosomal , double
stranded circular DNA
molecule.
• Vir genes helps in transfer of
T-DNA into plant cell.
• Small segment of Ti- plasmid
transferred to host plant &
integrated with genome i.e. T-
DNA.
• Agrobacterium induced
tumors synthesize variety of
unusual compounds- opines.

7. OPINES
• Agrobacterium induce tumors synthesize a
variety of unusual compounds called
opines.
• Types of opines:-
Octapine
Nopaline
Agropine
• These opines are catabolized by
agrobacterium to obtain energy.

8. HOW Ti- PLASMID CAUSE A
DISEASE?

9. T- DNA
• Only a small segment of Ti-
plasmid is transferred to the
host plant cell & gets
integrated with genome i.e. T –
DNA.
• It contains genes for tumor
formation (Tum) & nopaline
biosynthesis (Nos).
• T-DNA is bordered by 25 bp
repeats , required for excision
& transfer of DNA.

10. Ri- PLASMID
• The virulence plasmid of
A.rhizogenes is commonly
known as Ri- Plasmid (pRi).
• Agrobacterium rhizogene is a
soil borne , gram negative
bacterium.
• It causes hairy root disease in
plants .
• All strains of A.rhizogenes are
known to produce
agrocinopine.

11. HOW Ri –PLASMID CAUSE A
DISEASE?

12. DNA TRANSFER
• The insertion of a DNA fragment (gene of
interest) into a cloning vector & then its
introduction into a suitable host.
• The uptake of isolated plasmid directly by
plant protoplast can be done by following
DNA gene transfer methods :-
1. Electroporation.
2. Microprojectile bombardment.
3. Microinjection.

13. 1. ELECTROPORATION
• It involves the use of high
field strength electric
impulses .
• It results in the formation of
transient pores in the plasma
membrane through which
DNA enters & gets integrated
into the host cell genome.
• This technique is simple,
convenient & rapid.

14. 2. MICROPROJECTILE
BOMBARDMENT
• This method is used for
delivery of foreign genes into
plant cells or tissues .
• Exogenous DNA or RNA
molecules can be coated to the
surface of microscopic
tungsten microprojectiles.
• These are then accelerated to
high velocities by a particle
gun, enabling them to pierce
cell walls & membranes.

15. 3. MICROINJECTION.
• This technique involves animal
cells transformation at high
frequency .
• Protoplasts are surface attached
on a slide by embedding in
agarose or polylysine using a
holding pipette.
• DNA is transferred by injecting it
with microneedles into surface-
attached protoplast.
• After this the recipient cell is kept
in position by a suction holding
pipette.

16. REFERENCES.
• K.G.RAMAWAT – PLANT BIOTECHNOLOGY (2004) .
3rd EDITION, S.CHAND AND COMPANY Ltd. PAGE NO.
231-238, 183 .
• M.K. RAZDAN – INTRODUCTION TO PLANT TISSUE
CULTURE (2012). 2nd EDITION, OXFORD & IBH
PUBLISHING Co. Pvt. Ltd. PAGE NO. – 186-189.

17. THANK
YOU..