UNIVERSITY OF CALIFORNIA, DAVIS 
BERKELEY • DAVIS • IRVINE • LOS ANCELES • RIVERSIDE • SAN DIEGO • SAN FRANCISCO 
SANTA BARBARA • SANTA CRUZ 
COLLEGE OF AGRICULTURAL AND DAVIS, CALIFORNIA 95616 
ENVIRONMENTAL SCIENCES 
AGRICULTURAL EXPERIMENT STATION 
department of plant patholocy December 27, 1979 
Dr. Donald S. Fredrickson 
Director, National Institutes of Health 
Bethesda, Maryland 20205 
Dear Dr. Fredrickson: 
I would like to respond to the proposed revised NIH Guidelines for 
Recombinant DNA Research beginning on page 69210 of the Federal Register, 
Friday, November 30, 1979, Part VII. 
1. Section I-D-3 (under Prohibitions). "Deliberate creation by the use 
of recombinant DNA of a plant pathogen with increased virulence and 
host range beyond that which occurs by natural genetic exchange." 
I would like to see this statement eliminated from the guidelines. The 
inclusion of this statement in the guidelines originated during the 
early history of drafting the Guidelines. The statement was discussed 
at the USDA-NSF Invitational Workshop on Recombinant DNA Research in 
Relation to Plant and Animal Sciences, April 12-13, 1977. At that 
time little information was available on plant pathogens and many of 
us did not accept the scenaristic viewpoints about "creating" new 
plant pathogens. Still that statement remains in the current revision. 
I would like to document my argument for elimination of this statement. 
A. We have shown that Agrobacterium tumef aciens strains with limited 
host range and virulence (small gall production) can be altered by 
natural genetic means into a pathogen with broad host range and 
high virulence equivalent to but not exceeding that of wild type 
species with broad host range and high virulence character. I 
enclose a reprint documenting this. It is true that virulence and 
host range were increased by natural genetic means. However, the 
same type of experiment can be performed by inserting the virulence 
specifying genes by genetic transformation. If recombinant DNA 
molecules are used (which will be the case when Ti plasmid segments 
are cloned for functional analysis) , then it is a prohibitive 
experiment even though one is simply inserting the same genes by 
using a different technique. On one hand we are deliberately "creating" 
a plant pathogen and on the other the experiments seem to be exempt 
from the guidelines because it is a self-cloning experiment. 
[ 604 ] 
