BACKGROUNDBacillus thuringiensis (Bt) is a Gram‐positive bacterium that produces various insecticidal proteins used to control insect pests. Spodoptera frugiperda is a global insect pest which causes serious damage to crops, but bio‐insecticides currently available to control this pest have limited activity and so new ones are always being sought. In this study we have tested the hypothesis that a biomarker for strain toxicity could be found that would greatly facilitate the identification of new potential products.RESULTSUsing genomic sequencing data we constructed a linkage network of insecticidal genes from 1957 Bt genomes and found that four gene families, namely cry1A, cry1I, cry2A and vip3A, showed strong linkage. For 95 strains isolated from soil samples we assayed them for toxicity towards S. frugiperda and for the presence of the above gene families. All of the strains that showed high toxicity also contained a member of the vip3A gene family. Two of them were more toxic than a commercially available strain and genomic sequencing identified a number of potentially novel toxin‐encoding genes.CONCLUSIONSThe presence of a vip3A gene in the genome of a Bt strain proved to be a strong indicator of toxicity towards S. frugiperda validating this biomarker approach as a strategy for future discovery programs. © 2024 Society of Chemical Industry.

中文翻译：

---

基于杀虫基因连锁分析鉴定苏云金芽孢杆菌高毒抗草地贪夜蛾生物标志物


背景苏云金芽孢杆菌（Bt）是一种革兰氏阳性细菌，可产生多种用于控制害虫的杀虫蛋白。草地贪夜蛾是一种全球性害虫，对农作物造成严重损害，但目前可用于控制这种害虫的生物杀虫剂活性有限，因此一直在寻找新的杀虫剂。在这项研究中，我们测试了这样的假设：可以找到菌株毒性的生物标志物，这将极大地促进新的潜在产品的鉴定。结果利用基因组测序数据，我们构建了 1957 年 Bt 基因组杀虫基因的连锁网络，并发现了四个基因家族，即cry1A、cry1I、cry2A和vip3A，表现出很强的连锁性。对于从土壤样品中分离出的 95 个菌株，我们检测了它们对草地贪夜蛾的毒性以及上述基因家族的存在。所有表现出高毒性的菌株都含有 vip3A 基因家族的成员。其中两种菌株的毒性比市售菌株的毒性更大，并且基因组测序鉴定出许多潜在的新型毒素编码基因。结论 Bt 菌株基因组中 vip3A 基因的存在被证明是对草地贪夜蛾毒性的有力指标。验证这种生物标记方法作为未来发现计划的策略。 © 2024 化学工业协会。