Morphological and molecular variations within Helicotylenchus vulgaris

Helicotylenchus vulgaris is a plant-parasitic nematode reported from several countries in various biogeographical regions. During the survey on Helicotylenchus in Iran and the South African Plant-Parasitic Nematode Survey in South Africa, H. vulgaris was found in samples from northern and southern Iran and from two provinces in South Africa. Helicotylenchus vulgaris was identified based on morphological and molecular characteristics. The result based on the hierarchical clustering of the principal component analysis placed the South African and Iranian populations into different groups, while the British populations were put together with the Iranian populations. Besides, the phylogenetic analysis of four Iranian H. vulgaris based on 28S rDNA indicated that they group into two different clades. Median-joining network analysis using 28S rDNA grouped H. vulgaris into two different groups, with the South African (acc. nrs: HM014239 and HM014238) sequences having 65 and 67 step differences, whereas a population from Iran (MF996711) was placed in a different group. In conclusion, the results showed that variations exist among the diverse populations of H. vulgaris, as shown by both morphological and molecular characters. A detailed revision of the species is, however, should be studied using different genes.