Morphological, Morphometrical and Molecular Characterization of Oscheius siddiqii Tabassum and Shahina, 2010 (Rhabditida, Rhabditidae) from India with Its Taxonomic Consequences for the Subgenus Oscheius Andrássy, 1976

Abstract

An insect parasitic nematode belonging to the genus Oscheius was recovered from the agricultural soils from the Hapur district in western Uttar Pradesh, India. Morphological studies on this species exhibited its high resemblance with two Pakistani species: Oscheius siddiqii and O. niazii. No molecular data are available for these taxa but, morphologically, both species do not differ significantly from our strains and each other. Hence, these nematodes can be considered conspecific, and the correct name for this taxon is O. siddiqii, the first described species. The phylogenetic analyses of the ITS-, 18S-, and the 28S rDNA sequences showed that O. siddiqii is a sister taxon to the group formed by Oscheius microvilli, O. myriophilus, O. safricanus, and several unidentified Oscheius species. Additionally, our analyses show that based on molecular and morphological data, the species Oscheius rugaoensis and O. microvilli cannot be distinguished from O. chongmingensis and O. myriophilus, respectively, and are thus considered junior synonyms of these taxa. Furthermore, the available data are not sufficient to evaluate the status of Oscheius basothovii and O. safricanus, which are, in consequence, considered species inquirendae. These findings highlight the necessity of the proper morphological and molecular characterisation of the described Oscheius species.

Description ofOscheius cyrusn. sp. (Nematoda: Rhabditidae) as new entomopathogenic nematode from Iran

“…Geneious prime software (version 2019.1.3; ()) was used to assemble and trim the consensus sequence for all tree genes. According to Bhat et al (2021), legitimate and validated sequences of the genus and outgroup sequences were chosen for phylogenetic analysis. The sequences for all three amplified locus (ITS, SSU and LSU) were aligned using the ClustalX with default parameters and the alignment was manually edited in Molecular Evolutionary Genetics Analysis (MEGA) 7 (Kumar et al , 2016).…”

“…In Iran, few studies have been done on the identification, ecology, and biology of Oscheius spp., and few species including, Oscheius chongmingensis (Darsouei et al , 2014) ( Oscheius rugaoensis newly was proposed as a junior synonym of O . chongmingensis by Bhat et al , 2021), Oscheius necromenus , Oscheius onirici , O. Oscheius tipulae (Valizadeh et al , 2017; Karimi et al , 2018) and Oscheius myriophilus (Gholami Ghavamabad et al , 2021) have been reported until now.…”

Entomopathogenic potential of bacteria associated with soil-borne nematodes and insect immune responses to their infection

“…were isolated from specimens of Rhabditis regina [74]. Furthermore, numerous species of Oscheius are vectors of bacteria [75][76][77]. For instance, several species of Acinetobacter, Bacillus, Klebsiella, Enterobacter, Pseudomonas, Lysinibacillus and Alcaligenes have been isolated from different Oscheius species [30,78].…”

Genotypic relationships and phylogeography of the genus Oscheius (Rhabditidae: Rhabditomorpha) with a new entomopathogenic isolate of Oscheius tipulae Lam and Webster, 1971

“…The tree topology and the arrangement of the taxa showed congruency with those of the D2/D3-based molecular phylogenetic tree, however the original populations of O. siddiqii and O. niazensis Tabassum and Shahina, 2010 were not included in the molecular tree due to lack of molecular data. The morphology-based phylogenetic analysis showed a very close a nity of O. siddiqii Tabassum and Shahina, 2010 to O. shamimi Tahseen and Nisa, 2006 with well-supported posterior probability value (100%); whereas, O. niazensis Tabassum and Shahina, 2010 showed close a nity with the Indian population O. siddiqii [5] because of a shared character "separate/ free lip", although, both species differ from each other in the number of lateral lines (six vs eight).…”

“…The systematic position of the genus was frequently discussed and revised by several workers in the past [1,5,17,19]. The genus was divided into two species groups viz., insectivorusgroup and Dolichura-group [36,40].…”