Ovarian transcriptome profile from pre-laying period to broody period of Xupu goose

Abstract

Xupu goose, a breed from Hunan province, produces high quality and quantity of meat and liver. However, its egg production rate is low, with poor reproductive traits but strong broody performance. These characteristics decrease the economic value of Xupu goose significantly. Here, RNA-seq was used to analyze the transcriptome changes of ovaries of Xupu goose at different stages to explore the molecular mechanism of reproduction from the pre-laying period to the broody period. A total of 258 genes were differentially expressed in the 3 stages. These genes are associated with inflammation, reproduction, mutual recognition and adhesion between cells, and cytoskeleton formation, and so on. In particular, we report, for the first time, the expression patterns of MRP126, serglycin, TXNIP, and FZD2 during the pre-laying, egg-laying, and broody periods of goose ovaries. Functional analysis by GO annotation revealed that GO terms were mainly involved in actin, cell signal transduction and regulation, and cellular components. Three pathways, including focal adhesion (gga04510), ECM-receptor interaction (gga04512), and N-Glycan biosynthesis (gga00510), were significantly enriched in the three groups. These findings provide a basis for further exploration of profiles of goose ovaries to improve egg production of Xupu goose.

Keywords: Xupu goose; broody period; laying period; ovarian transcriptome; pre-laying period.

Figure 1

Validation of sequencing data by qPRC. Validation of the results for pre-laying period (T1), egg-laying period (T2) and broody period (T3). (A) T1 vs. T2; (B) T1 vs. T3; (C) T2 vs. T3. All data are presented as means ± SEM, x-axis individual genes whereas y-axis represents the fold change in expression determined by RNA-seq (gray bars) or qPCR (black bars). The representative genes are GCK (glucokinase), ITGB2 (integrin subunit beta 2), LCP1 (lymphocyte cytosolic protein 1), MPEG1 (macrophage expressed 1), PTAFR (platelet-activating factor receptor), SLA (Src-like-adaptor), STRA6 (stimulated by retinoic acid 6) and GAPDH (glyceraldehyde-3-phosphate dehydrogenase, house-keeping gene for qPCR).

Figure 2

Differentially expressed genes from the three reproduction periods. (A) Heat maps of DEGs from ovaries during pre-egg period (T1), laying-egg period (T2) and broody period (T3). The read counts of each cellular mRNA were normalized by the sum of the total reads. Colors from white to red represent upregulated cellular genes; colors from white to green represent downregulated cellular genes. (B) Pearson correlation analysis of T1, T2, and T3 groups. Volcano plot of corrected P values as a function of weighted fold change for mRNAs in T1 vs. T2 (C); T1 vs. T3 (D); (C) T2 vs. T3 (E). The vertical dotted line delimits up- and downregulation. Red plots represent significant upregulated genes and green plots represent significant downregulated genes (|log2-fold change|≥0, corrected P < 0.05). (F) A Venn diagram showed the relationships among T1, T2, and T3 groups of DEGs. A total of 258 DEGs were identified in all 3 groups. Abbreviation: DEGs, differentially expressed genes.

Figure 3

GO terms enrichment analysis of DEGs in ovaries. Histogram charts show the top 30 significantly enriched GO terms of T1 vs. T2 (A), T1 vs. T3 (B), T2 vs. T3 (C), which are classified as biological process (BP, red bar), cellular component (CC, green bar) and molecular function (MF, blue bar). Abbreviations: DEGs, differentially expressed genes; GO, gene ontology.

Figure 4

KEGG pathway enrichment analysis of DEGs in ovaries. Bubble charts represent the top 20 significantly enriched KEGG pathways of T1 vs. T2 (A), T1 vs. T3 (B), T2 vs. T3 (C). Size of each circle represents the number of DEGs in each pathway (larger circles represent more DEGs) and the color represents the P value of each pathway. Abbreviations: DEGs, differentially expressed genes; KEGG, Kyoto Encyclopedia of Genes and Genomes.