胰岛素对昆虫病原线虫生长发育、生殖力及致病力的影响

Effects of Insulin on Growth,Fecundity and Pathogenicity of Entomopathogenic Nematodes

昆虫病原线虫是一种极具潜力的生防因子,因其高效的杀虫特性而受到国际生防界的广泛关注,胰岛素作为一种蛋白质多肽,已被证实对昆虫、线虫等的生长发育、寿命均有重要调控作用。为了明确胰岛素对昆虫病原线虫的影响,本试验通过对经卡森斯氏线虫Steinernema kraussei 0657L和短尾异小杆线虫Heterorhabditis brevicaudis 0641TY侵染的大蜡螟Galleria mellonella注射不同浓度胰岛素,观测昆虫病原线虫的生活史及其对大蜡螟的致病力,以明确胰岛素对昆虫病原线虫生长发育、生殖力、致病力的影响。结果表明:胰岛素干预时间和干预浓度均可对卡森斯氏线虫0657L在寄主昆虫体内的生长发育产生影响,侵染当天(t)干预和高浓度(1:500)干预,会明显缩短其发育历期;侵染当天无论是高浓度还是低浓度的胰岛素干预,均会明显缩短短尾异小杆线虫0641TY的发育历期,且相比较卡森斯氏线虫0657L,胰岛素促进短尾异小杆线虫0641TY发育历期的效果更明显。在卡森斯氏线虫0657L侵染大蜡螟10 d后,注射低浓度的胰岛素,可显著提高其生殖力;在短尾异小杆线虫0641TY侵染大蜡螟1 d后,注射低浓度的胰岛素,可显著提高其生殖力。胰岛素对卡森斯氏线虫0657L致病力有影响,在24 h内高浓度胰岛素可显著缩短寄主昆虫的死亡时间,但是侵染36 h后,各处理间差异不显著;而对短尾异小杆线虫0641TY致病力无影响。综上所述,胰岛素对卡森斯氏线虫0657L和短尾异小杆线虫0641TY的发育和生殖力均有影响,且对卡森斯氏线虫致病力有影响。

Entomopathogenic nematodes(EPN)possess many attributes as biocontrol agents.They are safe to humans and generally safe to other nontarget organisms.Insulin,as a protein peptide,has been proved to play an important role in regulating the growth,development and lifespan of insects and nematodes.To investigate the effects of insulin on entomopathogenic nematodes,we studied the life span,fecundity and pathogenicity of Steinernema kraussei 0657L and Heterorhabditis brevicaudis 0641TY exposed to insulin and their pathogenicity to Galleria mellonella.The results showed that both the intervention time and the concentration of insulin could affect the growth and development of S.kraussei 0657L in the host insect.Intervention on the day of infection(t)and high concentration(1:500)could reduce the life span of S.kraussei 0657L,while on the day of infection,both high and low concentration of insulin intervention significantly shortened the life span of H.brevicaudis 0641TY,which was more prominent in H.brevicaudis 0641TY than in S.kraussei 0657L.After infection with S.kraussei 0657L for 10 days,low concentration of insulin increased its fertility significantly,while just after infection with H.brevicaudis 0641TY for 1 day,low concentration of insulin increased the fertility of H.brevicaudis 0641TY significantly.In addition,insulin had an effect on the pathogenicity of S.kraussei 0657L.High concentration of insulin applied within 24 h quickened the death of host significantly,which,however,disappeared at 36 h post application.Similar effects were not observed on the pathogenicity of H.brevicaudis 0641TY.Therefore,insulin affects the development and fecundity of S.kraussei 0657L and H.brevicaudis 0641TY and has an effect on the pathogenicity of S.kraussei 0657L.These findings will shed light on the use of entomopathogenic nematodes.