Phylogenetic relationships of 52 Eimeria species based on COI sequences

Abstract

Coccidiosis is an important protozoan disease of domestic animals, which frequently presents as simultaneous infections with multiple Eimeria species, however the relationships of Eimeria species are not clear at present. In this study, we sequenced the COI of E. tenella, E. mitis, E. anseri isolated from wintering Anser albifrons feces, and also downed 49 Eimeria species published in Genbank. The results indicated that no phylogenetic reconstruction supported monophyly of Eimeria species, which is different from previous studies, Eimeria dispersa may have arisen via host switching from another host.

Coccidiosis is an important protozoan disease of domestic animals, also is recognized as one of the most important diseases with great economic impact on wild birds and poultry industry throughout the world (Lin et al. 2011; Ogedengbe et al. 2014; Chengat Prakashbabu et al. 2017). The disease frequently presents as simultaneous infections with multiple Eimeria species (Apicomplexa: Eimeriidae) (Ogedengbe et al. 2013). Eimeria can cause serious damage to the digestive tract of the host, resulting in malabsorption of nutrients and diarrhea, which causes decreased body weight gain, and possibly lead to death, and has been one of the biggest challenges faced by the global poultry industry (Lin et al. 2011; Chengat Prakashbabu et al. 2017; Song et al. 2017). However, the relationships of Eimeria species are not clear at present (Ogedengbe et al. 2013; Liu et al. 2019).

COI gene provide useful markers for investigating population genetic structures, systematics and phylogenetics of organisms, it has been extensively used as genetic markers for phylogenetic analyses at different levels (Lin et al. 2011; Liu et al. 2019). Here, we sequenced the COI of three Eimeria species (E. tenella, E. mitis, E. anseri) isolated from wintering Anser albifrons feces which collected in Shenjin lake (E117°0′42.55″, N30°20′30.73″), Anhui province of China in January, 2019. The DNA samples were stored at −20 °C in the Cancer Cell Biology Laboratory, School of Life Sciences, Anhui Medical University (Sample codes are AHMUP20190101-AHMUP20190103). The COI sequences have been submitted to GenBank (accession number MN586863-MN586865). We also searched all the COI genes of Eimeria species which published in Genbank more than 450 bp in the length to this day.

The nucleotide compositions of the 52 COI sequences for Eimeria are biased toward A and T, with T being the most common nucleotide and G the least common. The mean total nucleotide composition was: A, 26.1%; C, 18.5%; G, 16.9%; and T, 38.5%; the average AT content (55.6%) being slightly higher than the CG content (44.4%), which is similar to the most Eimeria, in which the rarest nucleotide is G (Lin et al. 2011; Ogedengbe et al. 2014; Hafeez et al. 2015; Liu et al. 2019).

Phylogenetic trees were estimated using ML and BI methods, to study the phylogeny of the Eimeria species. Corresponding Isospora butcherae (KY801687) sequence was used as outgroup. Phylogenetic analyses of 52 Eimeria species based on COI revealed five distinct groups with high statistical support (Figure 1). No phylogenetic reconstruction supported monophyly of Eimeria species, is different from previous studies, Eimeria dispersa may have arisen via host switching from another host (Lin et al. 2011; Chengat Prakashbabu et al. 2017; Song et al. 2017). Though the inferred phylogenetic trees in this study provided new evidence for understanding the evolution of Eimeria species, the present dataset has its limitation in reconstruction of the intra-generic relationships.

Figure 1.

Phylogenetic trees based on COI sequeces of 52 Eimeria species by the ML and BI methods. Numbers at each node are bootstrap values from three analyses (Maximum likelihood/Bayesian inference). Notes: E. acervulina: FJ_236443, E. meleagrimitis: KC_346353, E. adenoeides: KC_346360, E. mitis: FR_796699, E. alabamensis: KU_351690, E. nafuko: JQ_993708, E. alorani: JQ_993701, E. necatrix: EU_025108, E. apionodes: JX_464221, E. nkaka: JQ_993697, E. arloingi: KX_857470, E. paludosa: KJ_767189, E. auburnensis: KU_351693, E. piriformis: JQ_993698, E. boholensis: MH_350860, E. purpureicephali: KU_140598, E. bovis: KU_351697, E. ranae: MH_698563, E. brasiliensis: KU_351698, E. subspherica: KU_351704, E. bukidnonensis: KU_351700, E. syrichta: MH_350859, E. burdai: JQ_993709, E. tamiasciuri: KT_184375, E. cahirinensis: JQ_993687, E. tenella: FJ_236453, E. callospermophili: JQ_993688, E. uptoni: KU_216013, E. Canadensis: KU_351701, E. vejdovskyi: JQ_993699, E. christenseni: KX_857468, E. vermiformis: MH_777577, E. cylindrical: KU_351702, E. intestinalis: JQ_993693, E. dispersa: HG_793048, E. irresidua: JQ_993694, E. exigua: JQ_993691, E. ivitaensis: MH_892075, E. falciformis: MH_777576, E. jerfinica: KU_216033, E. ferrisi: MH_777593, E. kaunensis: KU_216034, E. flavescens: JQ_993692, E. magna: JQ_993695, E. furonis: MF_774036, E. maxima: FJ_236459, E. gallopavonis: HG_793051, E. illinoisensis:KU_351703, E. hirci: KX_857469, E. tenella: MN_586863, E. mitis: MN_586864, E. anseri: MN_586865.

Nucleotide sequence accession number

The COI sequences of E. tenella, E. mitis and E. anseri have been assigned with GenBank accession numbers MN586863-MN586865.

Disclosure statement

The authors report no conflicts of interest.