Nitrogen-fixing cyanobacteria as gene delivery system for expressing mosquitocidal toxins of Bacillus thuringiensis ssp israelensis
Nitrogen-fixing cyanobacteria as gene delivery system for expressing mosquitocidal toxins of Bacillus thuringiensis ssp israelensis
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DOI：
10.1023/a:1008114929490
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发表时间：
2000-10-01
影响因子：
3.3
通讯作者：
Zaritsky, A
中科院分区：
文献类型：
--
作者：
Boussiba, S;Wu, XQ;Zaritsky, A
经典的生物防治是取代化学农药最成功和最有前途的方法。苏云金芽孢杆菌以色列亚种（Bti）是一种安全、有效的蚊媒防治剂。克服Bti的当前制剂的低功效和短半衰期的一种方法是通过在作为递送系统的重组蓝藻中表达毒素基因。在过去的十年中，已经进行了在蓝杆菌中表达Bti毒素的尝试。然而，转基因菌株的毒性非常低，即使在强启动子的调节下，也太低而不能在体内有效。两种Bti Cry蛋白最近在丝状固氮蓝藻Anabaena PCC 7120中共表达，产生了迄今为止具有最高毒性和稳定性的克隆。然而，为了获得持久的制剂，在从自然界分离的蓝藻菌株中表达Bti毒素基因将是有用的。该方法需要开发用于有效转化成此类菌株的系统。将这种重组菌株释放到开放环境中仍然是开发这种生物技术的主要障碍。
Classical biological control is the most successful and promising way to replace chemical pesticides. The subspecies israelensis of Bacillus thuringiensis (Bti) is a safe and efficient agent to control mosquito larvae and hence mosquito-borne diseases. One approach to overcome the low efficacy and short half-life in nature of current formulations of Bti is by expressing the toxin genes in recombinant cyanobacteria as a delivery system. Attempts to express Bti toxin in cyanoabcteria have been carried out during the last ten years. Toxicities of the transgenic strains were however very low, even under regulation of strong promoters, too low to be effective in vivo. Two Bti Cry proteins have recently been co-expressed in the filamentous nitrogen-fixing cyanobacterium Anabaena PCC 7120, resulting in clones with the highest toxicities and stabilities ever reached so far. However, to obtain a long-lasting preparation, it would be useful to express Bti toxin genes in cyanobacterial strains isolated from nature. This approach requires development of a system for effective transformation into such strains. Releasing such recombinant strains to open environments is still a major obstacle in exploiting this biotechnology.