بررسی ویژگی‌های ریخت‌شناختی و مولکولی گونه‌ها‌ی جنس Aporcella خاک‌های استان آذربایجان‌شرقی

The family Aporcelaimidae is a polyphyletic group with 231 known species that include 172 valid species belonging to 15 genera. These nematodes are cosmopolitan and one of the most abundant dorylaimids. In this study, species of the genus Aporcella were identified in different regions of East Azarbaijan province. These are moderately slender to slender nematodes with medium to large size. Cuticle three-layered, with similar refraction. Lip region offset with more or less distinct constriction. Odontostyle short and robust, with aperture occupying more than half its length. Guiding ring single, plicate. Odontophore rod-like. Pharynx enlarging gradually, with basal expansion occupying ca half of total neck length; S1N1 at about middle of DN-S1N2 distance. Female genital system didelphic-amphidelphic, vulva a transverse slit, pars refringens vaginae non sclerotized. Tail similar in both sexes, short, hemispherical to conical, usually about as long as anal body diameter. Spicules dorylaimoid, ventromedian supplements 3-17 in number. Aporcella resembles Aporcelaimellus, but can be easily distinguished in lacking pars refringens vaginae, its cuticle layers almost always show similar refraction and S1N1 is often slightly closer to DN than to S1N2. It is also comparable to Metaporcelaimus, but differs from this genus in terms of absence of pars refringens vaginae and tail morphology. In this study 500 soil samples were collected from the rhizosphere of various vegetation from East Azarbaijan province. Nematodes were extracted by conventional methods and fixed and transferred to glycerin using De Grisse method and after preparation the permanent slides, identification was carried out based on morphological and morphometric characteristics. In the molecular study, DNA of nematodes was extracted and amplified by the primers related to D2-D3 28S rDNA region. After sequencing, drawing of the phylogenetic tree using MrModel test 2.3 and Mrbayes Softwares were performed. In this survey, seven species of this genus were identified, including five un-described species namely Aporcella sp.1, Aporcella sp.2, Aporcella sp.3, Aporcella sp.4 and Aporcella sp.5 and two species, A. simplex and A. vitrinus are the first record for nematode fauna of Iran. The new species in the phylogenetic tree are located adjacent to two isolates of A. charidemiensis and, along with A. simplex, form a separate clade and distinct from other aporcelaimids and neighboring to the clade consisting the species belong to Discolaiminae and Tylencholaiminae. This shows that Aporcella does not share a common ancestor with other Aporcelaimidae and which is a polyphenetic group.