<p style="text-align: justify;">Event MON 15985 (tradename Bollgard II&reg;) was derived from the hybrid cotton variety DP50B, which was a cross between DP50 and transgenic Bollgard&reg; cotton line 531, by biolistic transformation with plasmid DNA containing the <i>cry2Ab2</i> gene originally isolated from <i>Bacillus thuringiensis</i> subsp. <i>kurstaki</i>. As a result, event 15985 expresses both the Cry1Ac and Cry2Ab2 insecticidal proteins and exhibits resistance to a range of lepidopteran pests such as the cotton bollworm, tobacco budworm, pink bollworm, and armyworm.</p>

<p style="text-align: justify;">As with other <i>B. thuringiensis</i>-derived delta-endotoxins, the Cry1Ac and Cry2Ab2 proteins exert their insecticidal activity by binding to specific receptors located on the brush border midgut epithelium of susceptible insect species. Following binding, cation-specific pores are formed that disrupt midgut ionic equilibrium leading to gut paralysis and eventual death due to bacterial sepsis. Cry1Ac and Cry2Ab2 are highly selective and are only active against lepidopteran insects. These proteins do, however, interact with different receptor sites in the target insects and it is expected that &ldquo;stacking&rdquo; these traits will result in increased protection against insect attack and a delay in the development of resistant insect populations.</p>

<p style="text-align: justify;">In addition to the <i>cry</i> genes conferring insect resistance, MON 15985 also contains the <i>nptII</i> and <i>aad</i> selectable marker genes (derived from the parental cotton line containing event 531) and the beta-D-glucuronidase (GUS) encoding <i>uidA</i> gene from <i>Escherichia coli</i>. This latter gene was introduced as a visually scorable marker gene to identify transformed plantlets in tissue culture. The GUS enzyme can be used to catalyze a colorimetric reaction resulting in the production of a blue colour in transformed cells.</p>

<p style="text-align: justify;">This product description will focus on those aspects of the risk assessment pertaining to the <i>cry2Ab2</i> and <i>uidA</i> gene products. For additional information on the safety assessment of <i>cry1Ac</i> and <i>nptII</i> gene products, the reader is directed to the product description for line MON 531.</p>
