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斯氏线虫Steinernema spp.是近年来发现的颇具希望的一种昆虫致病线虫,它与细菌Xenorhabdus nematophilus互惠共生。当斯氏线虫进入昆虫体腔后,排出的共生菌引起寄主败血症而使昆虫致死(poinar 1966)。因此,线虫对害虫的致病性一定程度上取决于感染期线虫所携带的共生菌。由于不同种的斯氏线虫携带不同亚种的共生菌,同种线虫中每条线虫所携带的共生菌的数量不同,所以对害虫显示了不同的致病力。在一般情况下,病原线虫的带菌率和每条线虫的带菌数目均与其致病力(毒力)成正相关
Steinernema spp. Is a promising insect nematode discovered in recent years. It interacts with the bacterium Xenorhabdus nematophilus. After the C. elegans enters the insect body cavity, the excreted symbionts cause host sepsis and kill the insects (poinar 1966). Therefore, the pathogenicity of nematodes to pests depends to some extent on the commensal bacteria carried by the nematodes during the infection. Because different species of nematodes carry commensal bacteria of different subspecies, the number of commensal bacteria carried by each nematode in the same species is different, so different virulence is shown. In general, the incidence of pathogenic nematodes and the number of each nematode carried are positively related to their virulence