DNA barcoding, phylogeny and phylogeography of the cyst nematode species of the Avenae group from the genus Heterodera (Tylenchida: Heteroderidae)

Abstract

SummaryAmong the recognised species groups ofHeterodera, theAvenaegroup is one of the largest with a total of 12 species. Ten of them,H. arenaria,H. aucklandica,H. australis,H. avenae,H. filipjevi,H. mani,H. pratensis,H. riparia,H. sturhaniandH. ustinovi, are morphologically closely related and represent theH. avenaespecies complex, and the other two,H. hordecalisandH. latipons, are morphologically more distinct from this complex. In this study we provide comprehensive phylogenetic analyses of several hundredCOIand ITS rRNA gene sequences from theAvenaegroup using Bayesian inference, maximum likelihood and statistical parsimony. Some 220COIand 11 ITS rRNA new gene sequences from 147 nematode populations collected in 26 countries were obtained in this study. Our study showed that theCOIgene is a powerful DNA barcoding marker for identification of populations and species from theAvenaegroup. A putatively new cyst nematode species related toH. latiponswas revealed from the analysis ofCOIand ITS rRNA gene datasets.COIgene sequences allow distinguishingH. arenaria,H. australisandH. sturhanifrom each other and other species. Problems of species delimiting of these species are discussed. The results of the analysis showed thatCOIhaplotypes corresponded to certain pathotypes of the cereal cyst nematodes. It is recommended that information onCOIhaplotypes of studied populations be included in research with these nematodes. Based on the results of phylogeographical analysis and age estimation of clades with a molecular clock approach, it was hypothesised that several species of theAvenaegroup primarily originated and diversified in the Irano-Anatolian hotspot during the Pleistocene and Holocene periods and then dispersed from this region across the world. Different geographic barriers, centres and times of origin might explain current known distribution patterns for species of theAvenaegroup. Possible pathways, including a long distance trans-Atlantic dispersal, and secondary centres of diversification are proposed and discussed.

Morphological and molecular characterization of Heterodera dunensis n. sp. (Nematoda: Heteroderidae) from Gran Canaria, Canary Islands

“…Using morphological and molecular characteristics, the species of this genus have been divided into nine groups, i.e., Afenestrata, Avenae, Bifenestra, Cardiolata, Cyperi, Goettingiana, Humuli, Sacchari, and Schachtii. Morphological characterization of Heterodera species is mainly done based on vulva-slit length, vulval cone fenestration, presence or absence of bullae and underbridge in female cysts, and stylet length, lateral field differentiation, tail length, and hyaline tail length in J2 (Subbotin et al, 2010). Since the last two decades, employing molecular data such as ITS and 28S of ribosomal DNA and COI gene of mitochondrial DNA to characterize Heterodera species has been a common practice, including DNA barcoding, phylogeny, and even phylogeography (Ferris et al, 1999;Toumi et al, 2013a;Subbotin et al, 2017Subbotin et al, , 2018.…”

Identification of Heterodera glycines (Tylenchida; Heteroderidae) Using qPCR

“…For this reason, a qPCR assay based on the differences of another gene sequence was developed to discriminate between the Heterodera avenae group species ( H. avenae , H. filipjevi , and H. latipons ) by targeting the CO I gene (Toumi et al, 2013, 2015). Several studies have adopted the CO I gene for the DNA barcoding of the Heteroderidae family (Powers et al, 2018; Subbotin et al, 2018; Vovlas et al, 2015). According to Subbotin et al (2018), the CO I gene is a powerful barcoding marker because each species of Heterodera has a unique sequence.…”

“…Several studies have adopted the CO I gene for the DNA barcoding of the Heteroderidae family (Powers et al, 2018; Subbotin et al, 2018; Vovlas et al, 2015). According to Subbotin et al (2018), the CO I gene is a powerful barcoding marker because each species of Heterodera has a unique sequence. Furthermore, the Consortium for the Barcode of Life proposed to barcode all known species according to the DNA sequence of the CO I gene (Blok and Powers, 2009).…”

Phylogeography of Chinese cereal cyst nematodes sheds lights on their origin and dispersal

“…Compared with the wide distribution of EHA population, CHA was only found in China. Subbotin et al ( 2018 ) showed that CHA has low mtCOI genetic diversity based on limited samples. This suggests that CHA may have gone through a strong bottleneck as a result of being associated with a domesticated host, and thus their dissemination may associate with its host.…”