To reveal the molecular mechanism of meat quality and excavate function genes related to tenderness in Chinese south cattle,this study selected Yunling,Wenshan and Simmental cattle at approximately 12 months of age as experimental object.Firstly,after slaughter,muscle tenderness of above cattle was measured at different stages of acid discharge (0,1,2,3,5,7d),which aimed at revealing the differences of meat quality among three varieties.Using transcriptome sequencing and bioinformatics analysis,we screened out differential expression genes related to meat quality,then real-time fluorescence quantification PCR was further performed.Results showed,meat tenderness of three varieties (Yunling,Wenshan and Simmental) showed a decreasing trend at different stages of acid discharge.At the same stage of acid discharge,the value of shear force showed the highest in Simmental,followed by Wenshan and Yunling,which indicated that the tenderness of Yunling was relatively good and Simmental was relatively poor.After cDNA library sequencing of longissimus dorsi between Yunling and Simmental,we screened out 3198 differential expression genes,of which 1750 genes were up-regulated in Yunling.Additionally,we found two important pathways related to meat quality,such as adipocytokine signaling pathway and protein processing in endoplasmic reticulum.Further qPCR verification and correlation analysis between gene expression level and shear force value,we ultimately identified Leptin and CAPN1 genes related to meat tenderness.This study screened and identified important pathways and key genes regulating meat tenderness,which will provide theoretical basis for genetic improvement of meat quality in Chinese south cattle.%为揭示南方黄牛肉质调控的分子机制并挖掘与肌肉嫩度相关的功能基因,本研究以1周岁左右的云岭牛、文山牛和中国西门塔尔牛为试验对象,屠宰后测定背最长肌不同排酸时间(0、1、2、3、5、7d)下剪切力变化,揭示不同黄牛品种肌肉嫩度的差异,利用RNA-Seq技术对背最长肌进行比较转录组学分析,并结合生物信息学筛选与肌肉嫩度调控相关的信号通路及差异表达基因,最后利用qPCR进行验证.结果表明:在宰后成熟过程中,黄牛肌肉嫩度表现为明显的下降趋势,且在同一个成熟时间点下,剪切力值表现为西门塔尔牛＞文山牛＞云岭牛,表明云岭牛嫩度较好,而西门塔尔牛嫩度相对较差;云岭牛与西门塔尔牛背最长肌2组文库经测序后,筛选出3 198个差异表达基因,其中云岭牛上调基因1 750个,KEGG功能注释发现2个与肉质调控相关的重要信号通路:脂肪细胞因子信号通路和内质网蛋白加工通路,结合qPCR验证、基因表达水平与剪切力值相关性分析,最终筛选出Leptin和CAPN12个可能肌肉嫩度相关的功能基因.本研究筛选与鉴定出南方黄牛肌肉嫩度相关信号通路及其关键基因,为今后南方黄牛肉质遗传改良奠定理论基础.
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