New approach for the study of mite reproduction: The first transcriptome analysis of a mite, Phytoseiulus persimilis (Acari: Phytoseiidae)

Many species of mites and ticks are of agricultural and medical importance. Much can be learned from the study of transcriptomes of acarines which can generate DNA-sequence information of potential target genes for the control of acarine pests. High throughput transcriptome sequencing can also yield sequences of genes critical during physiological processes poorly understood in acarines, i.e., the regulation of female reproduction in mites. The predatory mite, Phytoseiulus persimilis, was selected to conduct a transcriptome analysis using 454 pyrosequencing. The objective of this project was to obtain DNA-sequence information of expressed genes from P. persimilis with special interest in sequences corresponding to vitellogenin (Vg) and the vitellogenin receptor (VgR). These genes are critical to the understanding of vitellogenesis, and they will facilitate the study of the regulation of mite female reproduction. A total of 12,556 contiguous sequences (contigs) were assembled with an average size of 935 bp. From these sequences, the putative translated peptides of 11 contigs were similar in amino acid sequences to other arthropod Vgs, while 6 were similar to VgRs. We selected some of these sequences to conduct stage-specific expression studies to further determine their function.

Distribution of transcripts from a whole-body Phytoseiulus persimilis, 454 transcriptome with major categories of level 2 biological functions from a gene ontology (GO) analysis (n = 630 contigs).Figure optionsDownload as PowerPoint slideResearch highlights▶ First transcriptome was conducted of a mite, Phytoseiulus persimilis, using 454-pyrosequencing. ▶ 507,000 reads were assembled into 12,556 contigs with an average length of 935 bp. ▶ Putative functions were assigned to 4862 contigs (e-value: ≤1e−05) and 2958 contigs were novel. ▶ Sequence alignments, evolutionary relationships, conserved motifs and developmental expression studies revealed 11 contgs had similar translated amino acid sequences to vitellogenin (Vg) and not carrier protein and 6 contigs matched to several arthropod vitellogenin receptors (VgR). ▶ More detailed studies will be needed to understand the role of these putative Vgs and VgRs in female reproduction and how egg development is hormonally regulated in P. persimilis.