Comparative Muscle Quality and Multiomic Analyses in Wild-Type and Yellow-Mutant Triplophysa siluroides: TGF-β/BMP-Mediated Covariation and Breeding for Muscle Quality

This study investigated muscle quality differences between wild-type (WT) and yellow-mutant (YM) <i>Triplophysa siluroides</i>. Texture analysis showed WT <i>T. siluroides</i> had significantly greater hardness, gumminess, and resilience than YM. Histological and biochemical analyses ruled out myofiber diameter/density as drivers, instead identifying reduced collagen in YM as key, as confirmed by Picrosirius red staining, collagen quantification, and transmission electron microscopy. Transcriptomic and proteomic analyses revealed that TGF-β/BMP pathway suppression in YM resulted in downregulation of core molecules (e.g., <i>BMP2</i> and <i>SMAD1</i>), collagen-related genes (e.g., <i>COL1A1a</i> and <i>COL1A1b</i>), and ECM-related genes (e.g., <i>TNC</i> and <i>FN1</i>), potentially influencing collagen synthesis and ECM homeostasis. Notably, melanin gene <i>TYRP1</i> was also downregulated in YM <i>T. siluroides</i>, suggesting a link between pathway suppression, muscle quality alteration, and body pigmentation. The potential role of the BMP2-SMAD1-TYRP1 axis in the association between muscle quality and body colour provides novel mechanistic insights, offering molecular targets for the breeding of <i>T. siluroides</i> with superior commercial traits.