The filamentous fungus Beauveria bassiana is a natural pathogen of the greater wax moth Galleria mellonella. Infection with this fungus triggered systemic immune response in G. mellonella; nevertheless, the infection was lethal if spores entered the insect hemocel. We observed melanin deposition in the insect cuticle and walls of air bags, while the invading fungus interrupted tissue continuity. We have shown colonization of muscles, air bags, and finally colonization and complete destruction of the fat body—the main organ responsible for the synthesis of defense molecules in response to infection. This destruction was probably not caused by simple fungal growth, because the fat body was not destroyed during colonization with a human opportunistic pathogen Candida albicans. This may mean that the infecting fungus is able to destroy actively the insect's fat body as part of its virulence mechanism. Finally, we were unable to reduce the extremely high virulence of B. bassiana against G. mellonella by priming of larvae with thermally inactivated fungal spores.

中文翻译：

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大蜡螟感染丝状真菌白僵菌后的宿主-病原体相互作用

丝状真菌白僵菌是大蜡蛾 Galleria mellonella 的天然病原体。感染这种真菌引发了大蜡螟的全身免疫反应；然而，如果孢子进入昆虫血细胞，这种感染是致命的。我们观察到黑色素沉积在昆虫角质层和气囊壁中，而入侵的真菌中断了组织的连续性。我们已经展示了肌肉、气囊的定植，最后是脂肪体的定植和完全破坏——脂肪体是负责合成防御分子以应对感染的主要器官。这种破坏可能不是由简单的真菌生长引起的，因为在人类机会性病原体白色念珠菌定植期间，脂肪体没有被破坏。这可能意味着感染真菌能够积极破坏昆虫的脂肪体，作为其毒力机制的一部分。最后，我们无法通过用热灭活的真菌孢子激发幼虫来降低球孢杆菌对大蜡螟的极高毒力。