Qinchuan cattle, renowned for their distinctive meat quality, flavor, and exceptional environmental adaptability, represent a highly valuable genetic resource in beef cattle breeding. However, the molecular mechanisms underlying the formation of its meat quality traits, especially the genetic regulatory network of the core indicator of tenderness that affects consumer experience, are not yet clear. This study aims to employ transcriptomic techniques to identify candidate genes associated with tenderness in Qinchuan cattle, thereby providing a theoretical foundation for molecular breeding in beef cattle. Phenotypic analysis of meat quality revealed that the average shear force of the longissimus dorsi muscle (LDM) from 20 Qinchuan cattle was 115.43 ± 20.25 N, with significant differences among individuals (P < 0.01). Based on extreme tenderness differences, high shear force groups (HSF, n = 3) and low shear force groups (LSF, n = 3) were selected for transcriptome sequencing. A total of 286 differentially expressed genes (DEGs) were identified. Compared with the low shear force group, 247 genes were up-regulated and 39 genes were down-regulated in the HSF. GO and KEGG enrichment analyses indicated that these genes were significantly enriched in processes such as collagen binding, collagen trimer assembly, PI3K-Akt signaling pathway, and regulation of the actin cytoskeleton. Further protein-protein interaction (PPI) network analysis identified 5 hub genes associated with tenderness: POSTN, BGN, COL5A2, COL6A1 and COL6A2. Functional validation in cells showed that knockdown of POSTN expression significantly promoted bovine myoblast differentiation (up-regulation of MRF4, MYOG, and MYH3 expression, increase in MYH3 and MRF4 proteins), while inhibiting the expression of collagen deposition-related genes (CCN2 and LOX). Through transcriptomic and bioinformatic analyses, this study identified 5 core genes closely associated with meat tenderness in Qinchuan cattle and demonstrated that POSTN modulates tenderness formation through its dual role in regulating myogenic differentiation and collagen metabolism. These findings provide critical molecular targets for meat quality improvement in Qinchuan cattle and establish a theoretical foundation for molecular breeding of high-quality beef cattle.
Ma et al. (Fri,) studied this question.