Cultivated strawberry (Fragaria×ananassa) originated from four diploid ancestors: F. vesca, F. viridis, F. iinumae and F. nipponica.  Among them, F. vesca is the dominant subgenome for cultivated strawberry.  It is not well understood how differences in gene expression between diploid and octoploid strawberry contribute to differences during fruit development.  In this study, we used comprehensive transcriptomic analyses of F. vesca and F.×ananassa to investigate gene expression at the different stages of fruit development.  In total, we obtained 3 508 (turning stage) and 3 958 (red stage) differentially expressed genes with pairwise comparisons between diploid and octoploid.  The genes involved in flavonoid biosynthesis were almost upregulated in the turning stages of octoploid, and we also discovered a ripe fruit-specific module associated with several flavonoid biosynthetic genes, including FveMYB10, FveMYB9/11, and FveRAP, using weighted gene coexpression network analysis (WGCNA).  Furthermore, we identified the species-specific regulated networks in the octoploid and diploid fruit.  Notably, we found that the WAK and F-box genes were enriched in the octoploid and diploid fruits, respectively.  This study elucidates new findings on flavonoid biosynthesis and fruit size of strawberry with important implications for future molecular breeding in cultivated strawberry. 

MicroRNAs (miRNAs) have been widely identified in porcine testicular tissues and implicated as crucial regulators of proliferation, apoptosis, and differentiation in porcine spermatogenesis related cells.  However, the function roles of most of the miRNAs that have been identified in Sertoli cells are poorly understood.  In the present study, six experiments were conducted to study the regulatory role of miR-10b in porcine immature Sertoli cells.  In experiment 1, the results showed that the relative mRNA expression level of miR-10b in porcine testicular tissues decreased quadratically (P<0.001) with increasing age, while the relative mRNA expression level of DAZAP1 gene increased (P<0.001).  In addition, the mRNA expression of miR-10b was negatively (P<0.01) correlated with DAZAP1 mRNA expression (r=–0.550).  In experiment 2, the results from the bioinformatic analysis and a luciferase reporter assay demonstrated that miR-10b directly targeted the DAZAP1 gene in porcine immature Sertoli cells.  DAZAP1 mRNA and protein expressions were both regulated (P<0.05) by miR-10b.  In experiments 3 to 5, the over-expression of miR-10b or the siRNA-mediated knockdown of the DAZAP1 gene promoted (P<0.05) porcine immature Sertoli cell proliferation, as determined by the Cell Counting Kit-8 (CCK-8) assay and the 5-Ethynyl-2´-deoxyuridine (EdU) assay.  However, an annexin V-FITC/PI staining assay and the expression of cell survival-related genes indicated that over-expression of miR-10b or knockdown of DAZAP1 had no effect (P>0.05) on porcine immature Sertoli cell apoptosis.  In experiment 6, the co-transfection treatment results showed that miR-10b promoted (P<0.05) porcine immature Sertoli cell proliferation by targeting DAZAP1 gene.  Overall, these experiments demonstrated that miR-10b promotes porcine immature Sertoli cell proliferation by targeting the DAZAP1 gene.

MicroRNAs (miRNAs) are implicated in swine spermatogenesis via their regulations of cell proliferation, apoptosis, and differentiation.  Recent studies indicated that miR-34c is indispensable in the late steps of spermatogenesis.  However, whether miR-34c plays similar important roles in immature porcine Sertoli cells remain unknown.  In the present study, we conducted two experiments using a completely randomised design to study the function roles of miR-34c.  The results from experiment I demonstrated that the relative expression level of miR-34c in swine testicular tissues increased (P=0.0017) quadratically with increasing age, while the relative expression level of SMAD family member 7 (SMAD7 ) decreased (P=0.0009) with curve.  Furthermore, miR-34c expression levels showed a significant negative correlation (P=0.013) with SMAD7 gene expression levels.  The results from experiment II indicated that miR-34c directly targets the SMAD7 gene using a luciferase reporter assay, and suppresses (P<0.05) SMAD7 mRNA and protein expressions in immature porcine Sertoli cells.  Overexpression of miR-34c inhibited (P<0.05) proliferation and enhanced (P<0.05) apoptosis in the immature porcine Sertoli cells, which was supported by the results from the Cell Counting Kit-8 (CCK-8) assay, the 5-Ethynyl-2´-deoxyuridine (EdU) assay, and the Annexin V-FITC/PI staining assay.  Furthermore, knockdown of SMAD7 via small interfering RNA (siRNA) gave a similar result.  It is concluded that miR-34c inhibits proliferation and enhances apoptosis in immature porcine Sertoli cells by targeting the SMAD7 gene.