Liu Zhan-Chi, Zhou Liu, Wang Jia-Lin, Liu Xu-Sheng
Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, 152 Luoyu Road, Wuhan, 430079, China.
Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, 152 Luoyu Road, Wuhan, 430079, China.
Dev Comp Immunol. 2021 Apr;117:103986. doi: 10.1016/j.dci.2020.103986. Epub 2020 Dec 24.
Entomopathogenic fungi have high potential for controlling insect pests, although the slow killing speed has blocked their widespread application. To increase the virulence of entomopathogenic fungi, genetic modification can be employed. Egf1.0 is an immunosuppressive protein encoded by polydnavirus, carried by parasitoid wasp Microplitis demolitor, which blocks the prophenoloxidase (PPO) activation response of host insects. In this study, we explored the feasibility of genetically modifying entomopathogenic fungi with increased virulence by expressing Egf1.0. In comparison with the wild-type parents, the median lethal concentration (LC) of Beauveria bassiana expressing Egf1.0 against Helicoverpa armigera was reduced by 2.7-fold, and the median lethal time (LT) was reduced by 22.8%. In vitro assay showed that recombinant Egf1.0 was able to inhibit the PPO activation response of H. armigera. In vivo assay revealed that the expression of Egf1.0 in B. bassiana caused a higher degree of suppression to PPO activation response of H. armigera. These assays suggested that the increased virulence of the transgenic fungi is due to the increased ability to suppress the host insect's immune response. Moreover, colony growth, conidia yield, and germination assays revealed that the expression of Egf1.0 in B. bassiana had no effect on its growth and development. In conclusion, the expression of Egf1.0 can significantly enhance the pathogenicity of B. bassiana against host insects.
昆虫病原真菌在控制害虫方面具有很高的潜力，尽管其缓慢的致死速度阻碍了它们的广泛应用。为了提高昆虫病原真菌的毒力，可以采用基因改造的方法。Egf1.0是一种由多分DNA病毒编码的免疫抑制蛋白，由寄生蜂毁侧沟茧蜂携带，它能阻断宿主昆虫的前酚氧化酶（PPO）激活反应。在本研究中，我们探索了通过表达Egf1.0对昆虫病原真菌进行基因改造以提高其毒力的可行性。与野生型亲本相比，表达Egf1.0的球孢白僵菌对棉铃虫的半数致死浓度（LC）降低了2.7倍，半数致死时间（LT）缩短了22.8%。体外试验表明，重组Egf1.0能够抑制棉铃虫的PPO激活反应。体内试验表明，Egf1.0在球孢白僵菌中的表达对棉铃虫PPO激活反应的抑制程度更高。这些试验表明，转基因真菌毒力的提高是由于其抑制宿主昆虫免疫反应的能力增强。此外，菌落生长、分生孢子产量和萌发试验表明，Egf1.0在球孢白僵菌中的表达对其生长发育没有影响。总之，Egf1.0的表达可以显著增强球孢白僵菌对宿主昆虫的致病性。
