Distribution of Bacterial Endosymbionts of the <i>Cardinium</i> Clade in Plant-Parasitic Nematodes
Bacteria of the genus “<i>Candidatus</i> Cardinium” and related organisms composing the <i>Cardinium</i> clade are intracellular endosymbionts frequently occurring in several arthropod groups, freshwater mussels and plant-parasitic nematodes. Phylogenetic analyses based on tw...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-02-01
|
| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/24/3/2905 |
| Summary: | Bacteria of the genus “<i>Candidatus</i> Cardinium” and related organisms composing the <i>Cardinium</i> clade are intracellular endosymbionts frequently occurring in several arthropod groups, freshwater mussels and plant-parasitic nematodes. Phylogenetic analyses based on two gene sequences (16S rRNA and <i>gyrB</i>) showed that the <i>Cardinium</i> clade comprised at least five groups: A, B, C, D and E. In this study, a screening of 142 samples of plant-parasitic nematodes belonging to 93 species from 12 families and two orders using PCR with specific primers and sequencing, revealed bacteria of <i>Cardinium</i> clade in 14 nematode samples belonging to 12 species of cyst nematodes of the family Heteroderidae. Furthermore, in this study, the genome of the <i>Cardinium</i> cHhum from the hop cyst nematode, <i>Heterodera humuli,</i> was also amplified, sequenced and analyzed. The comparisons of the average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values for the strain <i>Cardinium</i> cHhum with regard to related organisms with available genomes, combined with the data on 16S rRNA and <i>gyrB</i> gene sequence identities, showed that this strain represents a new candidate species within the genus “<i>Candidatus</i> Paenicardinium”. The phylogenetic position of endosymbionts of the <i>Cardinium</i> clade detected in nematode hosts was also compared to known representatives of this clade from other metazoans. Phylogenetic reconstructions based on analysis of 16S rRNA, <i>gyrB, sufB, gloEL, fusA, infB</i> genes and genomes and estimates of genetic distances both indicate that the endosymbiont of the root-lesion nematode <i>Pratylenchus penetrans</i> represented a separate lineage and is designated herein as a new group F. The phylogenetic analysis also confirmed that endosymbionts of ostracods represent the novel group G. Evolutionary relationships of bacterial endosymbionts of the <i>Cardinium</i> clade within invertebrates are presented and discussed. |
|---|---|
| ISSN: | 1661-6596 1422-0067 |