Benfarhat-Touzri Dalel, Ben Amira Amal, Ben khedher Saoussen, Givaudan Alain, Jaoua Samir, Tounsi Slim
Biopesticides Team (LPIP), Centre of Biotechnology of Sfax, University of Sfax, P.O. Box "1177", 3018, Sfax, Tunisia.
J Basic Microbiol. 2014 Nov;54(11):1160-5. doi: 10.1002/jobm.201300142. Epub 2013 Jul 30.
Spodoptera littoralis, one of the major pests of many important crop plants, is more susceptible to Bacillus thuringiensis aizawai delta-endotoxins than to those of Bacillus thuringiensis kurstaki. Within the framework of the development of efficient bioinsecticides and the prevention against insect resistance, we tested the effect of mixing B. thuringiensis kurstaki delta-endotoxins and Photorhabdus luminescens cells on S. littoralis growth. The obtained results showed that the growth inhibition of this insect was more effective when B. thuringiensis kurstaki spore-crystal mixture and Photorhabdus luminescens cells were used in combination. Furthermore, this synergism is mainly due to the presence of Cry1Ac, which is one of the three delta-endotoxins that form the crystal of B. thuringiensis kurstaki strain BNS3 in addition to Cry1Aa and Cry2Aa. This work shows a possibility to use B. thuringiensis as a delivery means for Photorhabdus bacteria in order to infect the insect hemocoel and to reduce the risk of developing resistance in the target organism.
草地贪夜蛾是许多重要农作物的主要害虫之一，相较于苏云金芽孢杆菌库尔斯塔克亚种的δ-内毒素，它对苏云金芽孢杆菌 aizawai 亚种的δ-内毒素更为敏感。在高效生物杀虫剂研发及预防昆虫抗性的框架下，我们测试了将苏云金芽孢杆菌库尔斯塔克亚种的δ-内毒素与发光杆菌细胞混合对草地贪夜蛾生长的影响。所得结果表明，当苏云金芽孢杆菌库尔斯塔克亚种的芽孢-晶体混合物与发光杆菌细胞联合使用时，对该昆虫的生长抑制效果更佳。此外，这种协同作用主要归因于 Cry1Ac 的存在，Cry1Ac 是构成苏云金芽孢杆菌库尔斯塔克亚种 BNS3 菌株晶体的三种δ-内毒素之一，另外两种是 Cry1Aa 和 Cry2Aa。这项研究表明，有可能利用苏云金芽孢杆菌作为发光杆菌的传递载体来感染昆虫血腔，并降低目标生物产生抗性的风险。
