Two serpins from the endoparasitoid Tetrastichus brontispae Ferrière (Hymenoptera: Eulophidae) targe

• 作 者: Baozhen Tang Huajian Zhang You-ming Hou
• 机 构: Fujian Provincial Key Laboratory of Insect Ecology,Department of Plant Protection,Fujian Agriculture
• 出 处: 第四届全国生物入侵大会暨青年创新论坛
• 发表日期: 2014年5期
• 关键词: Octodonta nipae Parasite Tetrastichus brontispae Immunity Phenoloxidase cascade

　　The beetle Octodont nipae(Maulik)(Coleoptera: Chrysomelidae)is a serious invasive pest insect of palm plants in south China,and the endoparasite Tetrastichus brontispae Ferrière(Hymenoptera: Eulophidae)is a natural enemy of this pest,exhibits great potential in biocontrol of O.nipae.For successful parasitism,endoparasitoids often introduce or secrete various virulent factors to suppress host immunity.As a key component of the insect immune system,the PO cascade is known to be tightly regulated by serine protease and serpins,and the regulations of serine protease and serpins are suspected to contribute to an endoparasitoid immune suppressive strategy.However,the underlying mechanisms of this inhibition are largely unknown.Here,one prophenoloxidase-activating enzyme 3(PPAF3)and two serpins(SRPN5 and-6)from O.nipae and two T.brontispae serpins(SPN5 and-6)were isolated.PPAF3 consisted of two parts,a regulatory amino-terminal clip domain and a catalytic serine proteinase domain at the carboxyl terminus.The sequence similarity of SRPN5 and-6 with T.brontispae serpins(SPN5 and 6-),respectively,particularly in the amino acid residues surrounding the scissile bond in the reactive center loop(RCL),supported the prediction that T.brontispae serpins(SPN5 and 6-)might inhibit the O.nipae PPAF3.The results shed valuable light on host(O.nipae)manipulation mechanisms by T.brontispae,pave the way for the development of novel immune defense based management strategy of O.nipae.