两种昆虫激素对鹿儿岛被毛孢表观形态的影响

昆虫激素不仅能调控昆虫的生长发育，而且也是昆虫免疫系统的重要调节因子，因此当虫生真菌入侵昆虫寄主体腔并定殖时可能会受其影响。但定殖过程中虫生真菌与昆虫激素之间的直接作用关系尚不清楚。本研究利用不同浓度的蜕皮激素(20E)和保幼激素(JH)模拟鳞翅目昆虫家蚕体内的主要激素水平，对虫生真菌鹿儿岛被毛孢Hirsutella satumaensis进行培养，观察其表观形态特征的变化。结果表明，两种昆虫激素对鹿儿岛被毛孢的表观形态均有不同程度的影响。添加20E和JH培养后，鹿儿岛被毛孢菌落直径和菌丝生物量的变化差异不大；孢子的萌发率稍有下降；而菌落产生的色素和产孢量与对照组相比则呈现显著性变化。菌落色素圈和分生孢子的粘液厚度会随两种激素浓度的增加而增大，而产孢量随激素浓度增加呈先增加后降低的趋势，这说明鹿儿岛被毛孢定殖昆虫血体腔的过程中两种昆虫激素会抑制真菌的生长，而虫生真菌会适应性地做出应答反应，这对于进一步理解虫生真菌在昆虫血体腔中的定殖机理有重要意义。

Effects of two insect hormones on the morphological characters of Hirsutella satumaensis

Insect hormones play indispensable roles in the regulation of insect growth and development, as well as insect immune response. Consequently, the growth of entomopathogenic fungi may be influenced by these hormones when it colonized in the host haemocoele. However, it is unclear that whether there is a direct interaction between these fungi and insect hormones during the process of colonization. In this study, different concentrations of ecdysone (20E) and juvenile hormone (JH) that simulate the main hormone levels of lepidopteran silkworm were added to the agar plate cultivating Hirsutella satumaensis to observe the change of morphological characters of H. satumaensis. The results revealed that both of the two insect hormones had different great effects on the morphological characters of H. satumaensis. After incubation with 20E and JH, no significant differences in colony diameter and mycelial biomass of H. satumaensis were observed, and the spore germination rate was decreased slightly. However, the secretion of pigment and conidial production assumed dramatic changes as compared with that of the control group. The pigment circle and mucilage thickness of conidia were escalated with the increase of the concentration of the hormones, while the sporulation was boosted firstly and then declined slightly, indicating that the two insect hormones might inhibit the growth of entomopathogenic fungi during the colonization process, and these fungi could accordingly make adaptive response. This work is conducive to further reveal the colonization mechanism between entomopathogenic fungi and insect.