Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, 58030, México.
Facultad de Ciencias Agrotecnológicas, Universidad Autónoma de Chihuahua, Chihuahua, Chihuahua, 31350, México.
FEMS Microbiol Ecol. 2022 Oct 10;98(10). doi: 10.1093/femsec/fiac114.
Microbial volatile organic compounds may act as semiochemicals, inciting different behavioral responses in insects. Beauveria bassiana is an entomopathogenic fungus, and physiological and environmental factors are positively related to fungal virulence. In this study, we examined the volatile profiles produced by eight B. bassiana strains, isolated from soil plots and mycosed insect cadavers, with different speeds of kill and determined if these compounds induce oviposition behavior in Spodoptera frugiperda. Fungal volatilome analysis revealed differences between the isolates. Isolates from mycosed insects showed higher virulence, larger egg mass area and length, and a higher number of eggs by mass, than those obtained from soil. Furthermore, a dilution of the fungal odoriferous compounds increased the insect response, suggesting that S. frugiperda is highly susceptible to the fungal compound's fingerprint. Otherwise, the insect response to the natural blend of volatiles released by the fungus was different from that obtained with 3-methylbutanol, which was the most abundant compound in all isolates. The ability of an entomopathogen to produce volatiles that can induce olfactory stimulation of egg-laying behavior could represent an ecological adaptive advantage in which the entomopathogen stimulates the insect population growth.
微生物挥发性有机化合物可能作为信息素，在昆虫中引发不同的行为反应。球孢白僵菌是一种昆虫病原真菌，生理和环境因素与真菌的毒力呈正相关。在这项研究中，我们检测了 8 株球孢白僵菌菌株产生的挥发性图谱，这些菌株分别从土壤样地和感染昆虫尸体中分离得到，具有不同的致死速度，并确定这些化合物是否能诱导草地贪夜蛾产卵行为。真菌挥发物分析显示了分离株之间的差异。与从土壤中分离得到的菌株相比，来自感染昆虫的菌株具有更高的毒力、更大的卵质量面积和长度，以及更大的卵质量数量。此外，真菌气味化合物的稀释增加了昆虫的反应，表明草地贪夜蛾对真菌化合物的指纹具有高度的敏感性。另一方面，昆虫对真菌释放的天然挥发性混合物的反应与用 3-甲基丁醇获得的反应不同，3-甲基丁醇是所有分离株中含量最丰富的化合物。一种昆虫病原真菌产生能够诱导产卵行为嗅觉刺激的挥发物的能力，可能代表了一种生态适应性优势，即昆虫病原真菌刺激昆虫种群的生长。
