玫烟色棒束孢侵染对小菜蛾幼虫体内不同酶活的影响

在实验室条件下,测定了昆虫病原真菌玫烟色棒束孢Isaria fumosorosea的侵染对小菜蛾Plutella xylostella3龄幼虫体内酚氧化酶(PO)和不同抗氧化酶类,包括超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢(CAT)及谷胱甘肽S-转移酶(GSTs)活力的变化。结果表明,玫烟色棒束孢侵染小菜蛾3龄幼虫后,体内PO、SOD、POD、CAT和GSTs活力均受到明显的影响。其中感病小菜蛾幼虫体内的PO活力始终高于同期未感染的小菜蛾幼虫,当接菌40h时,酚氧化酶活力达到最大37.4U/g,为对照的2.6倍,而SOD、POD、CAT和GSTs活力在感病前期明显高于对照,接菌40–48h各种酶活力均达到最大,当接菌56h酶活力开始下降,64h时酶活力均明显低于对照。可见玫烟色棒束孢的侵染严重干扰了小菜蛾幼虫体内正常的生理活动。

Effects of Isaria fumosorosea infection on different enzyme activities in the larvae of Plutella xylostella

The activities of phenoloxidase (PO) and different antioxidative enzymes, including superoxide dismutase (SOD), perioxidase (POD), catalase (CAT) and glutathione S-transferase (GST) in the 3rd instar larvae of diamondback moth (Plutella xylostella) infected by Isaria fumosorosea were studied. The results showed that activities of PO and antioxidative enzymes in the 3rd instar larvae were significantly affected by I. fumosorosea. PO activity in the infected larvae was always higher than that in the control, and reached a value of 37.4U/g, being 2.6 times the PO activity of the control in 40h after inoculation. The antioxidative enzyme activities were higher than those of the controls at the beginning period of infection, and reached their peaks in 40–48h, then started to decline in 56h,finally became lower than those of the control in 64h, indicating that the physiological activities of P. xylostella larvae were disturbed by the infection of I. fumosorosea.