Expression and functional analyses of transformer-2 in Phytoseiulus persimilis and other genes potentially participating in reproductive regulation

Abstract Transformer-2 is an important sex-determining gene in insects and also plays roles in reproduction of Phytoseiid mites. We performed bioinformatics analyses for the transformer-2 ortholog in Phytoseiulus persimilis, measured its expression in different stages, and quantitatively identified its function in reproduction. This gene, termed as Pptra-2, encodes 288 amino acids with a conserved RRM domain. Its peak expression was observed in female adults, especially ca. 5 days after mating. Besides, expression in eggs is higher than that in other stages and male adults. When Pptra-2 was interfered through oral delivery of dsRNA, 56% females had their egg hatching rates decreased in the first 5 days, from ca. 100% to ca. 20%, and maintained at low levels during the rest of its oviposition period. To detect other genes functionally related to Pptra-2, transcriptome analyses were performed on the 5th day after mating. We compared mRNA expressions among interfered females with significant egg hatching rate decrease, interfered females with no significant egg hatching rate decrease, and the CK. A total of 403 differential genes were identified, among which 42 functional genes regulating female reproduction and embryonic development were screened and discussed.