Invasive Insect Biocontrol and Behavior Laboratory, USDA-ARS, Henry A Wallace Beltsville Agricultural Research Center, Beltsville, MD, 20705, USA.
Department of Entomology and Nematology, University of Florida, Gainesville, FL, 32611, USA.
BMC Res Notes. 2023 Jul 4;16(1):134. doi: 10.1186/s13104-023-06411-1.
This work was performed in support of a separate study investigating the activity of pesticidal proteins produced by Bacillus thuringiensis against the Asian citrus psyllid, Diaphorina citri. The fourteen Bacillus isolates chosen were selected from a large, geographically diverse collection that was characterized only by biochemical phenotype and morphology of the parasporal crystal, hence, for each isolate it was desired to determine the specific pesticidal proteins produced, assign each to a Bacillus cereus multilocus sequence type (ST), and predict their placement within the classical Bt serotyping system. In addition, phylogenetic distances between the isolates and Bacillus thuringiensis serovar type strains were determined by calculating digital DNA-DNA hybridization (dDDH) values among the isolates.
Based on the assembled sequence data, the isolates were found to be likely representatives of the Bt serovars kurstaki (ST 8), pakistani (ST 550), toumanoffi (ST 240), israelensis (ST 16), thuringiensis (ST 10), entomocidus (ST 239), and finitimus (ST 171). In cases where multiple isolates occurred within a predicted serovar, pesticidal protein profiles were found to be identical, despite the geographic diversity of the isolates. As expected, the dDDH values calculated for pairwise comparisons of the isolates and their apparent corresponding Bt serovar type strains were quite high (> 98%), however dDDH comparisons of the isolates with other serovar type strains were often surprisingly low (< 70%) and suggest unrecognized taxa within Bt and the Bacillus cereus sensu lato.
这项工作是为了支持一项单独的研究而进行的，该研究调查了苏云金芽孢杆菌产生的杀虫蛋白对亚洲柑橘木虱 Diaphorina citri 的活性。选择的 14 个芽孢杆菌分离株是从一个大型的、地理上多样化的分离株中选择的，这些分离株仅通过生化表型和伴孢晶体的形态特征进行了特征描述，因此，希望确定每个分离株产生的特定杀虫蛋白，将每个分离株分配到一个蜡状芽孢杆菌多位点序列类型 (ST)，并预测它们在经典 Bt 血清型系统中的位置。此外，通过计算分离株之间的数字 DNA-DNA 杂交 (dDDH) 值，确定了分离株与苏云金芽孢杆菌血清型菌株之间的系统发育距离。
根据组装的序列数据，发现这些分离株可能是苏云金芽孢杆菌血清型 kurstaki（ST8）、pakistani（ST550）、toumanoffi（ST240）、israelensis（ST16）、thuringiensis（ST10）、entomocidus（ST239）和 finitimus（ST171）的代表。在预测的血清型中出现多个分离株的情况下，尽管分离株的地理多样性很大，但杀虫蛋白谱是相同的。正如预期的那样，计算的分离株与其明显对应的苏云金芽孢杆菌血清型菌株之间的 dDDH 值非常高（>98%），但是分离株与其他血清型菌株之间的 dDDH 比较往往出乎意料地低（<70%），这表明苏云金芽孢杆菌和蜡状芽孢杆菌广义概念内存在未被识别的分类单元。
