Elleuch Jihen, Zghal Raida Zribi, Jemaà Mohamed, Azzouz Hichem, Tounsi Slim, Jaoua Samir
Biopesticides Team [L.P.I.P.], Centre of Biotechnology of Sfax, University of Sfax, P.O. Box 1177, 3018 Sfax, Tunisia.
Biopesticides Team [L.P.I.P.], Centre of Biotechnology of Sfax, University of Sfax, P.O. Box 1177, 3018 Sfax, Tunisia.
Int J Biol Macromol. 2014 Apr;65:148-54. doi: 10.1016/j.ijbiomac.2014.01.029. Epub 2014 Jan 18.
Cyt1Aa from Bacillus thuringiensis israelensis is known by its synergistical activity with B. thuringiensis and Bacillus sphaericus toxins. It is able to improve dipteran specific toxins activity and can prevent or overcome larval resistance to those proteins. The objective of the current study was to investigate the possible improvement of larvicidal activity of B. thuringiensis kurstaki expressing heterogeneous proteins Cyt1A and P20. cyt1A98 and p20 genes encoding the cytolytic protein (Cyt1A98) and the accessory protein (P20), respectively, were introduced individually and in combination into B. thuringiensis kurstaki strain BNS3. Immunoblot analysis evidenced the expression of these genes in the recombinant strains and hinted that P20 acts as molecular chaperone protecting Cyt1A98 from proteolytic attack in BNS3. The toxicities of recombinant strains were studied and revealed that BNS3pHTp20 exhibited higher activity than that of the negative control (BNS3pHTBlue) toward Ephestia kuehniella, but not toward Spodoptera littoralis. When expressed in combination with P20, Cyt1A98 enhanced BNS3 activity against E. kuehniella and S. littoralis. Thus, Cyt1Aa protein could enhance lepidopteran Cry insecticidal activity and would prevent larval resistance to the most commercialized B. thuringiensis kurstaki toxins.
来自以色列苏云金芽孢杆菌的Cyt1Aa以其与苏云金芽孢杆菌和球形芽孢杆菌毒素的协同活性而闻名。它能够提高双翅目特异性毒素的活性，并能预防或克服幼虫对这些蛋白质的抗性。本研究的目的是调查表达异源蛋白Cyt1A和P20的库斯塔克苏云金芽孢杆菌杀幼虫活性的可能提高情况。分别将编码溶细胞蛋白（Cyt1A98）和辅助蛋白（P20）的cyt1A98和p20基因单独或组合导入库斯塔克苏云金芽孢杆菌菌株BNS3。免疫印迹分析证明了这些基因在重组菌株中的表达，并暗示P20作为分子伴侣在BNS3中保护Cyt1A98免受蛋白水解攻击。对重组菌株的毒性进行了研究，结果显示BNS3pHTp20对粉斑螟的活性高于阴性对照（BNS3pHTBlue），但对海滨夜蛾没有活性。当与P20联合表达时，Cyt1A98增强了BNS3对粉斑螟和海滨夜蛾的活性。因此，Cyt1Aa蛋白可以增强鳞翅目Cry杀虫活性，并能防止幼虫对最商业化的库斯塔克苏云金芽孢杆菌毒素产生抗性。
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