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Abstract Background The golden pompano (Trachinotus ovatus) is an economically significant warm-water aquaculture species in China. The time required for sexual maturity of T. ovatus is relatively long. Consequently, it has prompted researchers to investigate gonadal development process of this fish. To gain further insight into the function of competing endogenous RNA (ceRNA) in the gonads of T. ovatus and the regulatory mechanism of the ceRNA network, whole transcriptome libraries were constructed from the testes and ovaries. Results Overall, a total of 96 differentially expressed microRNAs (DE-miRNAs), 2,338 differentially expressed messenger RNAs (DE-mRNAs), 973 differentially expressed long non-coding RNAs (DE-lncRNAs), and 94 differentially expressed circular RNAs (DE-circRNAs) were identified. Additionally, a ceRNA network was constructed, and enrichment analysis confirmed the involvement of numerous pathways in reproduction and gonadal development, including the TGF-β signaling pathway and GnRH signaling pathway. The ceRNA network analysis revealed that the oni-let-7d-1-p3 and PC-3p-112794_13 may play significant roles in T. ovatus gonadal development. And we have observed a possible relationship related to gonadal development involving R-spondin-1 (Rspo1), oni-let-7d-1-p3, and MSTRG.14909.1 (lnc-TGFβR). Dual-luciferase gene reporter system and fluorescence in situ hybridization analyses preliminary verified the regulation relationship between Rspo1 and oni-let-7d-1-p3, as well as lnc-TGFβR and oni-let-7d-1-p3 in the cytoplasm of sertoli cells. Conclusion It is hypothesized that the lnc-TGFβR functions as a sponge for oni-let-7d-1-p3, participating in regulating the process of testis development. These findings could enhance our understanding of ncRNAs in gonadal development. It also provides new insight into the function of ncRNAs and the regulatory relationship of ceRNA between males and females. These results might contribute to discussions on the regulation of ncRNA during gametogenesis.

IntroductionCitrus tristeza virus (CTV) is a threat to the citrus production and causes severe economic losses to the citrus industry. Ethylene response factors (ERFs) play important roles in plant growth and stress responses. Although ERF genes have been widely studied in model plants, little is known about their role in biological stress responses in fruit trees, such as citrus. CsERF1 belongs to the citrus AP2/ERF transcription factor family.MethodsTo determine the role of CsERF1 on CTV resistance in citrus and the effects of the exongenous hormone application on CsERF1 in citrus, the expression of related genes was quantitatively analyzed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) in this study.ResultsThe expression profile showed that the expression level of CsERF1 in roots was significantly lower under CTV infection than in healthy plants, while the expression level in stems was significantly increased. CsERF1 responded to exogenous salicylic acid (SA) and methyl jasmonate (MeJA) treatments. The CTV titer in RNAi-CsERF1 transgenic sweet orange plants significantly increased. Furthermore, CsERF1-overexpressing and RNAi-CsERF1 transgenic sweet orange plants exhibited differential expression of genes involved in jasmonic acid (JA) and SA signaling.DiscussionThese results suggest that CsERF1 mediates CTV resistance by regulating the JA and SA signaling pathways. The results of this study provide new clues as to the citrus defence response against CTV. It is of great significance to create citrus germplasm resources resistant to recession disease.