Morphological and molecular identification of Spinibdella lignicola (Canestrini, 1886) (Trombidiformes: Bdellidae)

Abstract

In October 2019, specimens of Spinibdella lignicola (Canestrini, 1886) (Trombidiformes: Bdellidae) were isolated from a soybean sample in Anqing City, Anhui Province, China. The morphological features were observed under a digital microscope and digital pathological scanning system, and the DNA of a single mite was extracted. Cytochrome oxidase subunit I (Cox1) and the small ribosomal subunit RNA (18S rRNA) gene sequences were obtained by Polymerase Chain Reaction (PCR) amplification and sequencing, and BLAST comparison was performed. The base composition was analyzed using MEGA7.0 software, and a phylogenetic tree was constructed using the maximum likelihood method. PCR amplification results showed the Cox1 gene to be 1238 bp in length and the 18S rRNA gene to be 1740 bp in length. The content of the Cox1 gene (A+T) was 71.0%, and that of 18S rRNA gene (A+T) was 52.7%. In the phylogenetic tree constructed based on Cox1 gene and 18S rRNA gene, Spinibdella lignicola and the other mites in Bdelloidea gathered in one branch. The Cox1 gene and 18S rRNA gene can be useful tools for use as molecular markers for species identification.