Survey on entomopathogenic nematodes in families steinernematidae and heterorhabditidae in North Khorasan

Entomopathogenic nematodes (EPNs) are one of the most important biocontrol agents. The identification of these agents has become very important issue due to the developing trend of their applications in the recent decades. A survey for isolation of EPNs was conducted in Bojnourd region, from three different habitats. Subsequently, morphological and molecular characteristics as well cross breeding tests were used to identify those native isolates. Among 50 soil samples, 5 samples were positive including 10 populations. Both Steinernema and Heterorhabditis genera were isolated using Galleria trap method. According to morphological and morphometric characters, four isolates, namely Boj1, Boj7, Boj8 and Boj9 were from "feltiae" species group of Steinernema. Another isolate, HBoj was a member of "bacteriophora" species group of Heterorhabditis. The phylogenetic analysis on sequence data of ITS showed that Boj1, Boj7, Boj8 and Boj9 attributed to “feltiae” group, while HBoj isolate belonged to “bacteriophora” group. Reconstruction of phylogenetic trees using ITS sequences showed that four isolates, Boj1, Boj7, Boj8 and Boj9 were grouped in a clade with other species of "feltiae" group (of Steinernema). Phylogenetic analysis on those genes for HBoj isolate grouped this isolate with H. bacteriophora species in a clade. Crossbreeding tests between Boj1, Boj7, Boj8 and Boj9 isolates and reference strain of S. feltiae showed that Boj1 belongs to the S. feltiae species. The other three isolates (Boj7, Boj8 and Boj9) were species from Steinernema genus. Current survey is the first study on native populations of EPNs in North Khorasan.