Afrina sporoboliae sp. n. (Nematoda: Anguinidae) Associated with Sporobolus cryptandrus from Idaho, United States: Phylogenetic Relationships and Population Structure

Abstract

The dropseed gall-forming nematode, Afrina sporoboliae sp. n., is described from seed galls of Sporobolus cryptandrus (Poaceae: Chloridoideae: Sporobolinae) collected in Idaho, USA. This is the third report of an Afrina species in North America and the first report of this genus in a natural plant population on this continent. Morphological, morphometric, and molecular analyses placed this nematode in genus Afrina and demonstrated that it differs from Afrina hyparrheniae and Afrina spermophaga by having longer body and stylet lengths for females and males, and from Afrina wevelli by the absence of tip irregularities on the tails of female and presence of lips noticeably protruding beyond the body contour. The new species has several characters that overlap with Afrina tumefaciens, but differs from this species by inducing seed galls, whereas Afrina tumefaciens induces ovoid galls on stems, leaves, and in flower heads. Evolutionary relationships of Afrina sporoboliae sp. n. with other representatives of the family Anguinidae are presented based on analysis of the internal transcribed spacer (ITS)1-5.8S-ITS2 rRNA and the D2-D3 regions of the rRNA genes. Analysis of 270 sequences of the cox1 gene from 25 populations of Afrina sporoboliae sp. n. revealed seven haplotypes with sequence divergence up to 5%. This study did not demonstrate a significant positive relationship between genetic difference and geographic distance. Seed gall nematodes are important quarantine pests in many countries. The association of this and other seed gall nematodes with Rathayibacter species and their ability to serve as vectors, especially of R. toxicus, is of concern for U.S. agriculture.

Molecular Phylogenetic Characterization of Anguina tritici (Steinbuch, 1799) Filipjev, 1936 (Rhabditida: Anguinidae) on Barley from Iraq

“…In this tree, the newly generated sequences have formed a maximally supported clade with previously deposited sequences of A. tritici from wheat. Anguina agropyronifloris Norton, 1965 formed a clade with A. tritici sequences from wheat and barley, a similar relationship that was already resolved (Barrantes-Infante et al, 2018). The current phylogenetic analysis also confirmed the monophyly of Anguina and polyphyly of Ditylenchus (Aliverdi et al, 2021).…”

Description of Nothotylenchus savadkoohensis n. sp. (Rhabditida, Anguinidae) from Iran based on morphological and molecular data

“…The relevant sequences used in ITS phylogeny also yielded in cladogenesis events, showing this marker could be used in future molecular taxonomic studies on the genus, as commonly used for other anguinid taxa (e.g. Vovlas et al, 2016 ; Barrantes-Infante et al, 2018 ).…”