Abdullah Mohd Amir F, Moussa Saad, Taylor Milton D, Adang Michael J
InsectiGen, Inc., 425 River Road, Athens, GA 30602-2771, USA.
Pest Manag Sci. 2009 Oct;65(10):1097-103. doi: 10.1002/ps.1798.
Specific Bacillus thuringiensis Berliner (Bt) toxins are effective against a narrow spectrum of species. While specificity is an advantage for limiting adverse effects on non-target organisms, it is also the primary drawback of Bt's application for controlling multiple pest species in agriculture, forestry and other areas. Recently, it was reported that a small toxin-binding fragment of Manduca sexta (Joh.) cadherin acts as a synergist of Bt toxins to M. sexta, Heliothis virescens F. and Helicoverpa zea (Boddie). These insects are quite susceptible to the Cry1A toxins. The first aim of the present study was to determine if longer-sized fragments of M. sexta cadherin differed in the level of toxin enhancement. The second aim was to examine enhancement of Bt toxins against relatively Bt-tolerant insects Agrotis ipsilon (Hufn.) and Spodoptera exigua (Hübner).
Cadherin fragments longer than previously reported had improved synergistic properties. Significant enhancement of Bt Cry1A toxins against A. ipsilon and S. exigua was found. A cadherin fragment also increased Cry1C toxicity to S. exigua.
The commercial development of this synergist has the potential to widen the spectrum of Bt toxicity to other important agricultural lepidopteran insect pests and thus increase its usefulness in agriculture.
特定的苏云金芽孢杆菌（Bt）毒素仅对窄谱物种有效。特异性虽有利于限制对非靶标生物的不利影响，但也是Bt在农业、林业及其他领域用于防治多种害虫时的主要缺点。最近有报道称，烟草天蛾（Manduca sexta）钙黏蛋白的一个小毒素结合片段可作为Bt毒素对烟草天蛾、烟芽夜蛾（Heliothis virescens）和玉米螟（Helicoverpa zea）的增效剂。这些昆虫对Cry1A毒素相当敏感。本研究的首要目的是确定烟草天蛾钙黏蛋白更长片段在毒素增强水平上是否存在差异。第二个目的是检测Bt毒素对相对耐Bt的昆虫小地老虎（Agrotis ipsilon）和甜菜夜蛾（Spodoptera exigua）的增强作用。
比先前报道的更长的钙黏蛋白片段具有更好的协同特性。发现Bt Cry1A毒素对小地老虎和甜菜夜蛾有显著增强作用。一个钙黏蛋白片段还增强了Cry1C对甜菜夜蛾的毒性。
这种增效剂的商业开发有可能拓宽Bt对其他重要农业鳞翅目害虫的毒性谱，从而提高其在农业中的实用性。
