Morphology, morphometric and molecular study of geographical isolates of an entomopathogenic nematode, Steinernema feltiae (Rhabditida: Steinernematidae) from north-west of Iran

The study was intended to investigate the morphological, morphometric and molecular characterization of eight geographical isolates of the entomopathogenic nematode Steinernema feltiae from northwest of Iran. The results showed no detectable morphological variations, but significant morphometric variations were recorded among the isolates. Clustering based on morphometry of infective juveniles, classified the isolates in the following three separate groups: group I consists of IRA30 and IRA25; group II includes IRA21, IRA23, IRA34, IRA28 and IRA21 and group III contains of IRA17. Clustering the isolates based on the male's morphometric characters, yielded nearly similar results and four groups were constructed as follows: group I is made up of IRA22, IRA23 and IRA21; group II holds IRA25, IRA34 and IRA28; group III contains IRA30 and IRA17 constitutes group IV. No intraspecific variation was observed among PCR-RFLP patterns of the native isolates resulted from16 restriction enzymes but significant variations were recorded within the isolate Pumping by HinfI, MspI and MboI. Although these markers serve as effective tools in separating the native isolates from the exotic ones, they are unable to detect variations among native isolates. Therefore, only ITS-rDNA sequence based phylogenetic analysis can effectively clarify the intraspecific variations of S. feltiae.