Transcript No Slide Title

GM Citrus with
Potential to Control
Greening
Dean W. Gabriel
Plant Pathology Department
University of Florida, Gainesville
and
Integrated Plant Genetics, Inc.
Alachua
Strategies for greening disease control
o No practical resistance breeding.
o Eradication impossible.
o Chemical control of insects may require 25 sprays per year.
o Genetically modified (GM) citrus (add a resistance gene).
Citrus greening, likely trapped in dooryard citrus, nationwide.
6 year lag from psyllid establishment to greening diagnosis.
APHIS/PPQ
intercepted the
vector
40 times in US
ports between
1985-98.
Why don't chemicals work on greening?
Canker bacteria
Greening bacteria
How to make a "GMO"
1
2
Nucleus
1. Start with DNA cloning vector.
2. Add gene of interest + plant selection gene.
3. Add cloned genes on vector to specialized bacterial pathogen.
4. Contact pathogen with target plant cell.
5. The pathogen injects the cloned genes into the plant cell, and the
genes are guided to the nucleus by DNA vector.
 Transformation process for GM Citrus
1. In a test tube, construct a gene encoded on vector DNA.
2. Add the vector DNA to a specialized bacterial pathogen.
3. Contact wounded citrus with the pathogen; the vector
DNA is injected by the pathogen into the plant cell.
--Essenberg & Richardson
 Transformation process for GM Citrus
1
2
Greenhouse
testing
Bacteria with cloned
genes applied to cut
end of citrus stem section.
Antibiotic selection applied.
Grafting onto rootstock
4 weeks --- 26% juvenile stem pieces survive;
1/2 of these are transformed
Mature Valencia & Hamlin regenerated
Juvenile grapefruit after grafting
May, 2008: Growth of transgenic citrus trees, each with 1 of 3
IPG DiseaseBlock genes.
Current status: GM citrus trees currently
being evaluated by IPG.
Technology (IP) is co-owned by UF.
Citrus has natural defenses
Transgenes that interfere with
defense are more susceptible...
Citrus has natural defenses
Harder to prove are transgenes that enhance defense... a
negative result (determined by PCR). To date, negative.
IPG DiseaseBlock® added
Transgenic tobacco as proxy... to date negative
IPG DiseaseBlock® added
GMOs can be accepted in the U.S.
Transgenic and nontransgenic papaya in Hawaii.
Work by: D. Gonsalves, Cornell U.; S. Ferreira and R. Manshardt, U.Hawaii; M. Fitch,
USDA; J. Slightom, Pharmacia
Transgenic 'UH Rainbow' to be graded in a commercial packinghouse.
Adoption Rates: Principal GM Crops in US
100
90
Percent of Crop
80
70
60
Soybean
Corn
Cotton
50
40
30
20
10
0
1996
1997
1998
1999
2000
Year
2001
2002
2003
2004
The Regulatory Process--Who's minding the Store?
 NIH mandated IBC review
 USDA-APHIS facility review
• USDA-APHIS field-release approval
• USDA-APHIS shipping authority
approval
• USDA-APHIS permission to
commercialize or non-regulatory status
(public comment, 12-24 mo)
The Regulatory Process
• EPA experimental use permit (if > 10 acres)
• EPA determines if limits needed on % gene
product (public comment, 24-30 mo.)
• EPA product registration (public comment)
• FDA review (public comment (12-18 mo.)
Earliest time to market: 2015
Integrated Plant Genetics, Inc.
IPG Research Sponsored by:
Southern Gardens Citrus
USDA-APHIS
NSF
Fischer USA
Goldsmith Plants
12085 Research Drive
Alachua, Florida 32615 USA
http://www.ipgenetics.com
[email protected]