Lazarte J Nicolás, Valacco María Pía, Moreno Silvia, Salerno Graciela L, Berón Corina M
Instituto de Investigaciones en Biodiversidad y Biotecnología (INBIOTEC) - CONICET and Fundación para Investigaciones Biológicas Aplicadas (FIBA), Vieytes 3103, Mar del Plata, Buenos Aires Province 7600, Argentina.
Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales, Facultad de Ciencias Exactas y Naturales, 1428 Ciudad Autónoma de Buenos Aires, Argentina.
J Invertebr Pathol. 2021 Jul;183:107563. doi: 10.1016/j.jip.2021.107563. Epub 2021 Feb 24.
The insecticidal proteins of Bacillus thuringiensis are used in formulations of spore-crystal complexes and their genes have been incorporated into several crops, providing a model for genetic engineering in agriculture. Despite the variability of the Cry proteins described so far, it is still necessary to look for toxins with a broad spectrum of action, since a significant number of pests are not controlled with the available Cry proteins. It is also important to provide alternatives to address the problem of insect resistance, which has already appeared with the use of formulations and with transgenic plants that express cry genes that code for insecticidal proteins. The FCC 7 strain was characterized by the ultrastructural parasporal body under optical and electronic microscopy, and for the detection of Cry8-type proteins by genomic and proteomic approaches. The identity of the strain and the presence of putative toxin encoding genes, and virulence factors analyzed by Illumina Miseq 1500 platform genomic sequencing, was confirmed. The identity of the two Cry8 proteins that make up the parasporal body was confirmed by MALDI-TOF/TOF. To expand knowledge about the insecticidal activity of this strain, we conducted preliminary tests against the cotton boll weevil, Anthonomus grandis. Here we report the characterization of a novel B. thuringiensis isolate native to Argentina (FCC 7) toxic against A. grandis. The strain shows a rounded parasporal body harboring mainly a protein of about 140 kDa and two different types of Cry8 proteins. Through whole-genome sequencing, we identified the presence of two cry8-like crystal protein genes, one vpa-like and two vpb-like genes, and multiple virulence factors, deepening the knowledge of a strain that had already been described as toxic against some lepidopterans and coleopterans, including Spodoptera frugiperda, Anticarsia gemmatalis, Tenebrio molitor and Diabrotica speciosa.
苏云金芽孢杆菌的杀虫蛋白被用于芽孢 - 晶体复合物制剂中，其基因已被整合到多种作物中，为农业基因工程提供了一个模型。尽管目前已描述的Cry蛋白具有变异性，但仍有必要寻找具有广泛作用谱的毒素，因为大量害虫无法被现有的Cry蛋白所控制。提供解决昆虫抗性问题的替代方法也很重要，昆虫抗性问题已经在使用制剂以及表达编码杀虫蛋白的cry基因的转基因植物中出现。通过光学和电子显微镜对FCC 7菌株的超微结构伴孢晶体进行了表征，并通过基因组和蛋白质组学方法检测Cry8型蛋白。通过Illumina Miseq 1500平台基因组测序，确认了该菌株的身份以及推定的毒素编码基因和毒力因子的存在。通过基质辅助激光解吸电离飞行时间/串联飞行时间质谱（MALDI - TOF/TOF）确认了构成伴孢晶体的两种Cry8蛋白的身份。为了扩展对该菌株杀虫活性的了解，我们针对棉铃象甲（Anthonomus grandis）进行了初步测试。在此，我们报告了一种来自阿根廷的新型苏云金芽孢杆菌分离株（FCC 7）对棉铃象甲有毒性的特性。该菌株显示出圆形的伴孢晶体，主要含有一种约140 kDa的蛋白质和两种不同类型Cry8蛋白。通过全基因组测序，我们鉴定出存在两个cry8样晶体蛋白基因、一个vpa样基因和两个vpb样基因以及多个毒力因子，加深了对该菌株的了解，该菌株已被描述为对一些鳞翅目和鞘翅目昆虫有毒性，包括草地贪夜蛾、银纹夜蛾、黄粉虫和南美玉米根虫。
