Identification and Functional Study of Potential Receptors Involved in Vitellogenesis of Female Banana Shrimp Fenneropenaeus merguiensis

Abstract

One of several molecular factors control ovarian development in organisms is receptors which play an initial role in signaling pathways in several physiological processes, including reproduction. This study aimed to identify the potential receptors involved in the control of female banana shrimp, Fenneropenaeus merguiensis, reproduction. The ovarian transcriptome derived from 4 developmental stages was constructed from Illumina RNA sequencing and bioinformatics analysis. A total of 53,763 transcripts was de novo assembled, and 663 genes were identified as receptors. Among them, 1 8 5 receptors were differentially expressed during ovarian development. The 15 differentially expressed receptor genes related to ovarian maturation were selected to validate for their expressions by qRT- PCR. In this study bone morphogenetic protein receptors (BMPR) were further characterized and studied their function in shrimp. Both saxophone (FmSax), a BMPR type I, and FmBMPR type II (FmBMPRII) were mainly expressed in eyestalks. The mRNA expression of FmSax was increased at the mature stage whilst expression of FmBMPRII was high at the late vitellogenic stage in both ovary and hepatopancreas. To study the role of FmSax, the double-stranded RNA specific to FmSax (dsSax) was produced in Escherichia coli. On day 7 after the injection of dsSax to female F. merguiensis shrimps, FmSax expression was significantly suppressed, and vitellogenin (Vg) and FmBMPRII expressions were significantly increased in both ovary and hepatopancreas. In addition, the knockdown of FmSax led to induce oocyte proliferation in vivo. These suggested that FmSax positively controls Vg synthesis, but negatively regulates oocyte proliferation in shrimp.