Formation of autotriploid Carassius auratus and its fertility-related genes analysis

Chongqing Wang,Shaojun Liu,Huan Qin,Li Yang,Chun Zhao,Qinbo Qin,Xu Huang,Yuxin Zhang,Xidan Xu,Tingting Yu,Xiang Luo

doi:10.1186/s12864-021-07753-5

Abstract

BackgroundFormation of triploid organism is useful in genetics and breeding. In this study, autotriploid Carassius auratus (3nRR, 3n = 150) was generated from Carassius auratus red var. (RCC, 2n = 100) (♀) and autotetraploid Carassius auratus (4nRR, 4n = 200) (♂). The female 3nRR produced haploid, diploid and triploid eggs, whereas the male 3nRR was infertile. The aim of the present study was to explore fertility of potential candidate genes of 3nRR.ResultsGonadal transcriptome profiling of four groups (3 females RCC (FRCC), 3 males 4nRR (M4nRR), 3 males 3nRR (M3nRR) and 3 females 3nRR (F3nRR)) was performed using RNA-SEq. A total of 78.90 Gb of clean short reads and 24,262 differentially expressed transcripts (DETs), including 20,155 in F3nRR vs. FRCC and 4,107 in M3nRR vs. M4nRR were identified. A total of 106 enriched pathways were identified through KEGG enrichment analysis. Out of the enriched pathways, 44 and 62 signalling pathways were identified in F3nRR vs. FRCC and M3nRR vs. M4nRR, respectively. A total of 80 and 25 potential candidate genes for fertility-related in F3nRR and M3nRR were identified, respectively, through GO, KEGG analyses and the published literature. Moreover, protein-protein interaction (PPI) network construction of these fertility-associated genes were performed. Analysis of the PPI networks showed that 6 hub genes (MYC, SOX2, BMP4, GATA4, PTEN and BMP2) were involved in female fertility of F3nRR, and 2 hub genes (TP53 and FGF2) were involved in male sterility of M3nRR.ConclusionsEstablishment of autotriploid fish offers an ideal model to study reproductive traits of triploid fish. RNA-Seq data revealed 6 genes, namely, MYC, SOX2, BMP4, GATA4, PTEN and BMP2, involved in the female fertility of the F3nRR. Moreover, 2 genes, namely, TP53 and FGF2, were related to the male sterility of the M3nRR. These findings provide information on reproduction and breeding in triploid fish.

Highlights

Formation of triploid organism is useful in genetics and breeding
Fertility of autotriploid Carassius auratus Autotriploid Carassius auratus (3nRR) were generated by crossing female Carassius auratus red var (RCC) and male Autotetraploid Carassius auratus (4nRR) during the breeding season (Figs. 1a, b and c, 2 and 3a, b and c; Table 1)
Testes of RCC and 4nRR (Fig. 4a, b) contained spermatogonia (SG), spermatocytes (SC) and a large number of mature spermatid (ST), whereas the mature sperm was not observed in 3nRR (Fig. 4c)

Summary

Introduction

Formation of triploid organism is useful in genetics and breeding. Autotriploid Carassius auratus (3nRR, 3n = 150) was generated from Carassius auratus red var. The aim of the present study was to explore fertility of potential candidate genes of 3nRR. Polyploid organisms have three or more chromosome sets. Development of gonads is critical to fertility in sexually reproducing organisms especially in triploids and is tightly regulated by complex processes [2]. Sexual differentiation and gametogenesis are important processes during gonadal development. Any abnormality in these events can result in infertility. Several genes implicated in sexual determination and differentiation have been reported [3,4,5]. Gametogenesis, including oogenesis and spermatogenesis, are regulated by complex mechanisms and several regulatory

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