Insecticidal activity of Beauveri bassiana ERL1170-egfp against Tribolium castaneum

Background
Beauveria bassiana is one of the commercially available entomopathogenic fungi (EPF), and a number of isolates with high virulence and broad host spectrum have been used to control agricultural and forest pests. Although the functional importance of genes in EPFs’ pathogenesis have been extensively studied, the precise ultrastructural mechanism of the fungal infection, particularly penetration of the host insect cuticles, is not well understood.
Results
In this study, we investigated the morphology and ultrastructure of the larval cuticle of the red flour beetle, Tribolium castaneum, after treatment with B. bassiana ERL1170 expressing an enhanced green fluorescent protein (Bb-eGFP). The Bb-eGFP showed high virulence against the larvae, with approximately 90% mortality at 48 h after treatment (HAT) and 100% at 72 HAT under our infection conditions. In these larvae, the regions of the body wall with flexible cuticles, such as the ventral and ventrolateral thorax and abdomen, b...

背景
球孢白僵菌（Beauveria bassiana）是目前已商业化应用的昆虫病原真菌（entomopathogenic fungi, EPF）之一，多个兼具高毒力与广谱宿主范围的菌株已被用于农林害虫的生物防治。尽管昆虫病原真菌致病过程中相关基因的功能重要性已得到广泛研究，但该类真菌侵染宿主的精确超微结构机制，尤其是穿透宿主昆虫体壁的具体过程，仍尚未被充分阐明。
结果
本研究针对表达增强型绿色荧光蛋白（enhanced green fluorescent protein, eGFP）的球孢白僵菌ERL1170菌株（Bb-eGFP）处理后的赤拟谷盗（Tribolium castaneum）幼虫体壁的形态与超微结构展开了分析。实验结果显示，Bb-eGFP对赤拟谷盗幼虫具有显著毒力：在本研究的侵染条件下，处理后48小时（48 HAT）幼虫死亡率约为90%，72 HAT时死亡率达100%。在此类处理幼虫中，体壁柔软的区域，如腹面、胸腹侧面及腹部的体壁区域，b...