209 A Single-Cell Atlas of Bovine Skeletal Muscle Tissue Reveals Mechanisms Underlying Differences in Quality between Wagyu and Brahman Beef

Abstract Wagyu cattle are renowned for their premium beef characterized by abundant intramuscular fat (IMF). In contrast, Brahman, a popular breed in the southern coastal area of US, generally produces tough meat with scarce IMF. However, mechanisms underlying differential quality between 2 breeds still largely unknown. Here, using single-cell RNAseq (scRNAseq), we report atlas bovine skeletal muscle tissue. Multiple fibro/adipogenic progenitor (FAP) subpopulations were identified, including an endomysial adipogenic subpopulation and perimysial fibrogenic subpopulation. Further analysis comparing individual FAP Brahman identified stronger expression pro-adipogenic genes higher pro-fibrogenic Overexpression CFD, gene upregulated FAPs, enhanced efficiency FAPs. Moreover, CFD FAPs was positively correlated IMF content. Interestingly, not mouse models adipogenesis, suggesting that is cattle-specific regulator formation. Cell-cell communication reveals significant differences CFD+ CFD- interactions other cell types, further important role growth development.