a study of a native isolate of an entomopathogenic nematode, heterorhabditis bacteriophora and its symbiont, photorhabdus luminecens subsp. laumondii

entomoparasitic nematodes (epn) are among the very important pest control agents. among the related groups within these nematodes, two families namely steinernematidae and heterorhabditidae are more important than the others. due to commercial application of these agents in pest control, extensive research has been carried out to identify the different species of these nematodes throughout the world. during a survery on the occurrence of epn in mashhad, a population of heterorhabditis genus was isolated from the soil. based upon morphological and morphometric traits, the isolated species was determined as h. bacteriophora. the its rdna region in the nematode was amplified and sequenced. in a phylogenetic analysis as based on mp and nj methods, this isolate stood with other populations of h. bacteriophora. the symbiotic bacterium associated with this nematode was characterized based on phenetic data as well as on 16s rdna sequence. the results revealed this bacterium as photorhabdus luminescens ssp. laumondii. this presents the first comprehensive repot of this bacto-helminthic complex in iran.