家蚕感染球孢白僵菌后4种抗菌肽基因的表达分析

【目的】阐明家蚕(Bombyxmori)抗菌肽对球孢白僵菌感染的应答模式,为揭示家蚕及鳞翅目昆虫抗真菌机制提供参考依据。【方法】利用实时荧光定量PCR检测家蚕被球孢白僵菌感染后抗菌肽基因cecropinA、gloverin2、lebocin1/2和lysozyme的表达情况,比较4种抗菌肽在家蚕脂肪体、血淋巴、马氏管和中肠中不同时间点的表达差异。【结果】经球孢白僵菌诱导后,cecropinA基因在家蚕脂肪体中的最高上调表达倍数为10.2倍,在血淋巴中的最高上调表达倍数为13.2倍,在马氏管中感染初期显著上调表达(P<0.05,下同),在中肠中感染后期显著上调表达;gloverin2基因在家蚕脂肪体中出现2次上调表达过程,最高上调表达倍数为15.7倍,在血淋巴中感染前期呈上调表达,在马氏管中略呈下调表达,中肠中的gloverin2基因在接种后16~48 h呈显著上调表达,最高上调表达倍数为6.7倍;lebocin1/2基因在家蚕脂肪体和血淋巴中的最高上调表达倍数分别为19.4和22.4倍,在马氏管中仅在接种后16 h呈显著上调表达,在中肠中则是接种后24~48 h呈显著上调表达;lysozyme基因在家蚕脂肪体中显著上调表达,在血淋巴和马氏管中感染初期也呈显著上调表达,但在中肠中的表达无明显规律。【结论】cecropinA、gloverin2、lebocin1/2和lysozyme基因在球孢白僵菌侵染家蚕的过程中均不同程度地被诱导上调表达,尤其在家蚕脂肪体和血淋巴中较明显,由此推测这4种抗菌肽在抵御球孢白僵菌的侵染过程中发挥重要作用。

Expression of four antimicrobial peptide genes in Bombyx mori infected with Beauveria bassiana

Objective]The present study was conducted to evaluate response pattern of antimicrobial peptides in Bom-byx mori against Beauveria bassiana infection in order to provide beneficial reference for researches on antifungal mecha-nism of B. mori and other lepidoptera insects. Method]The expression patterns of antimicrobial peptide genes cecropinA, gloverin2, lebocin1/2 and lysozyme in B. mori after being infected with B. bassiana were detected using real-time fluores-cence quantitative PCR. The differential expressions of the four antimicrobial peptide genes in fat body, hemolymph, malpighian tubule and midgut at different time points were compared. Result]After being induced by B. bassiana, the expression of cecropinA was up-regulated by 10.2 times to the maximum in fat body and 13.2 times to maximum in hemolymph. The expression of cecropinA was also significantly up-regulated in malpighian tubule at early stage of the in-fection ( P<0 . 05 , the same below ) , and in midgut at middle-late stages of the infection . Up-regulated expression of gloverin2 occurred twice in fat body and the maximum re-regulated expression multiple was 15.7 times. The expression of gloverin2 up-regulated in hemolymph at earlier stage but down-regulated in malpighian tubule. It also up-regulated in mindgut after 16-48 hours of infection, with maximum up-regulated multiples reaching 6.7 times. The expression of lebocin1/2 up-regulated in fat body by 19.4 times to utmost limit and by 22.4 times to the maximum in hemolymph. It also up-regulated significantly in malpighian tubule after 16 hours of infection and in midgut after 24-48 hours of infection. The expression of lysozyme significantly up-regulated in fat body, and also significantly up-regulated in hemolymph and malpighian tubule at earlier stage of infection. But the expression in midgut showed no obvious regulation . Conclusion]The expressions of antimicrobial peptide genes cecropinA, gloverin2, lebocin1/2 and lysozyme up-regulated to differ-ent extents after B. mori infected by B. bassiana, especially in fat body and hemolymph of B. mori. The results suggest that cecropinA, gloverin2, lebocin1/2 and lysozyme may play important roles in B. mori antifungal process against B. bassiana infection.