Department of Chemistry and Biology, Toronto Metropolitan University, 350 Victoria Street, Toronto, ON, M5B 2K3, Canada.
Parasitol Res. 2024 Feb 3;123(2):121. doi: 10.1007/s00436-024-08145-w.
Chemical defences against parasites and pathogens can be seen in a wide range of animal taxa, including insect pests such as the red flour beetle Tribolium castaneum. Antimicrobial quinone-based secretions can be used by these beetles to defend against various parasites, particularly the fungal entomopathogen Beauveria bassiana. While quinone secretions can inhibit B. bassiana growth, it is unknown how long they remain effective or how individual secretion compounds contribute to growth inhibition. Here, we tested each individual component of the quinone secretions (methyl-1,4-benzoquinone, ethyl-1,4-benzoquinone, and 1-pentadecene), as well as two mixed solutions that represent the composition range found in natural T. castaneum secretions, after aging for 0, 24, or 72 h. The two quinone compounds equally contributed to B. bassiana inhibition, but their efficacy was significantly reduced after 24 h, with no growth inhibition after 72 h. This indicates that quinones protect insects against B. bassiana for only a limited time, perhaps requiring constant secretion into the environment to effectively defend against this fungal threat. Future investigations may consider the extent to which quinone secretions are effective against other parasites, as well as how their ability to cause parasite damage changes with compound age.
昆虫化学防御机制在多种动物类群中都有体现，包括红粉甲虫等农业害虫。这些甲虫可以利用基于醌类的抗菌分泌物来抵御各种寄生虫，特别是真菌性昆虫病原真菌白僵菌。虽然醌类分泌物可以抑制白僵菌的生长，但尚不清楚它们的有效期有多长，以及单个分泌物化合物对生长抑制的贡献如何。在这里，我们测试了醌分泌物（甲基-1,4-苯醌、乙基-1,4-苯醌和 1-十五烯）的各个成分，以及两种代表天然红粉甲虫分泌物组成范围的混合溶液，它们在老化 0、24 或 72 小时后的效果。这两种醌类化合物对抑制白僵菌的作用相当，但在 24 小时后其效果显著降低，72 小时后则完全没有抑制作用。这表明醌类物质只能在有限的时间内保护昆虫免受白僵菌的侵害，可能需要不断向环境中分泌才能有效抵御这种真菌威胁。未来的研究可能需要考虑醌分泌物对其他寄生虫的有效程度，以及其引起寄生虫损伤的能力随化合物年龄的变化。
