Abstract: 【Aim】 To identify and explore the functions of cohesin complex subunits ZcSOLO and ZcSUNN in the reproductive processes of female and male Zeugodacus cucurbitae, thereby providing a basis for elucidating the role of the cohesin complex in meiosis and reproductive regulation of Z. cucurbitae. 【Methods】 The amino acid and nucleotide sequences of ZcSOLO and ZcSUNN of Z. cucurbitae were obtained through sequence alignment in the NCBI database, and the coding sequences (CDSs) of Zcsolo and Zcsunn were cloned from the cDNA that was synthesized from the total RNA extracted from the ovaries of mature Z. cucurbitae, subsequently sequenced and bioinformatically analyzed. The expression levels of Zcsolo and Zcsunn across different developmental stages ［embryo (15 s, and 1, 2, 3, 6, 12, 18 and 24 h after egg laying), larva (1-, 3- and 7-day-old), pupa (1-, 5- and 9-day-old) and adult (1-, 5-, 7-, 10- and 15-day-old)］ and 10-day-old adult tissues (head, thorax, abdomen, leg, testis and ovary) of Z. cucurbitae were examined by qPCR. RNAi-mediated knockdown of Zcsolo and Zcsunn in the 3-day-old adult of Z. cucurbitae was performed via dsRNA injection. Then the ovarian development of female adults was observed under a microscope. The ovarian area, the morphology and size of gonads, and the number of eggs laid in 10 d and egg hatching rate after mating were measured.【Results】 The correct CDSs of Zcsolo and Zcsunn of Z. cucurbitae were cloned. The CDS of Zcsolo consists of five exons with the length of 2 493 bp, while that of Zcsunn contains 15 exons with the length of 2 736 bp. SOLO and SUNN of Z. cucurbitae and Drosophila melanogaster shared very similar three-dimensional structure with high homology. Zcsolo and Zcsunn were specifically highly expressed in adult gonads, suggesting their roles related to fecundity. RNAi-mediated downregulation of Zcsolo and Zcsunn delayed the ovarian development and reduced the number of mature ovarian follicles. When the female adults after RNAi of Zcsolo and Zcsunn mated with the wild-type male adults, the number of eggs laid by female adults within 10 d and egg hatching rate significantly decreased. When the male adults after RNAi of Zcsolo and Zcsunn mated with the wild-type female adults, the number of eggs laid by the wild-type female adults within 10 d was not affected significantly, but the egg hatching rate after fertilization significantly reduced, indicating impaired male adult fecundity after RNAi of Zcsolo and Zcsunn. 【Conclusion】 This study demonstrates that Zcsolo and Zcsunn are essential for the fecundity of female and male Z. cucurbitae, providing a theoretical foundation for pest control strategies based on reproductive interference.

Key words: Zeugodacus cucurbitae, cohesin; Zcsolo, Zcsunn, fecundity, RNA interference