<p style="text-align: justify;">The oxynil family of herbicides is active against dicotyledenous plants by blocking electron flow during the light reaction of photosynthesis.</p>

<p style="text-align: justify;">One gene from the bacteria Klebsiella pneumoniae subspecies ozaenae has been introduced into the canola variety Westar providing a field level of tolerance to oxynil herbicides.</p>

<p style="text-align: justify;">The gene codes for a bacterial enzyme, nitrilase, which hydrolyses ioxynil and bromoxynil into non-phytotoxic compounds.</p>

<p style="text-align: justify;">The expression of the nitrilase gene is linked to a promoter and an enhancer which control gene expression. The nitrilase gene is linked to a polyadenylation signal from an Agrobacterium gene.</p>

<p style="text-align: justify;">The gene is expressed at a level of 1 microgram nitrilase per milligram of total protein in leaves and approximately 100-fold less in seeds.</p>

<p style="text-align: justify;">The nitrilase protein showed no significant homology with any known toxins or allergens in the Genebank and Swiss-Pro databases. The nitrilase protein was also shown to have low stability under simulated gastric conditions. The enzyme which confers oxynil tolerance is a bacterial version of an enzyme that is ubiquitous in nature including monocot plants such as corn, wheat and barley, and therefore would not be expected to be toxic or allergenic. Brassica napus variety Westar was transformed using a disarmed non-pathogenic Agrobacterium tumefaciens vector; the vector contained the transfer DNA (T-DNA) region of an A. tumefaciens plasmid from which virulence and disease causing genes were removed, and replaced with the oxynil tolerance gene. The T-DNA portion of A. tumefaciens plasmids are generally known to insert randomly into the plant&#39;s genome and the insertion is usually stable, as was shown to be the case in Oxy-235. Rh&ocirc;ne Poulenc has provided information on segregation and from Southern blot analysis that demonstrates that Oxy-235 has a single genetic insert, consisting of a single copy of the oxynil tolerance gene.</p>

<p style="text-align: justify;">Oxy-235 is several generations removed from the original transformant. Mendelian inheritance of the herbicide tolerance, and Southern analyses of third-generation material show the stability of the introduced traits.</p>

<p style="text-align: justify;">&nbsp;</p>
