Integrated volatile metabolomics and transcriptomics provide insights into the formation of characteristic flavor in gynogenetic grass carp and its offspring

To investigate the muscle quality differences and their underlying mechanisms among grass carp with different genetic backgrounds, this study analyzed muscle quality traits, volatile metabolomics, and transcriptomic of gynogenetic grass carp (GGC), disease-resistant grass carp (DRGC) and grass carp (GC). Compared to GC, the muscle of GGC exhibited higher water-holding capacity, hardness, and chewiness, while DRGC displayed greater gumminess in its muscle (P < 0.05). Using GC × GC-TOFMS analysis, a total of 2826 volatile flavor compounds (VFCs) were identified, with significant differences observed in VFCs types and relative abundances among the three varieties. Through multivariate statistical analysis, 296 differential VFCs were screened (VIP > 1, P < 0.05). By combining relative odor activity values (ROAVs), seven characteristic VFCs (VIP > 1, ROAV >0.1) were further identified as potential markers for variety discrimination and quality evaluation. Transcriptomic analysis, including differential expression analysis and weighted gene co-expression network analysis, identified several potential key genes, including sirt1, hsdl2, capzb, nmnat1, atic, stbd1, and arfgap3, which may influence the formation of characteristic flavor through regulating target metabolic pathways. This study revealed the flavor profiles of GGC and DRGC, and explored the potential mechanisms of characteristic flavor formation, providing scientific insights for improving muscle flavor through breeding.