Abstract: This aim of the study was to analyze the transcriptome and metabolome data by WGCNA technology, and explore the regulatory mechanism of donkey meat tenderness. Healthy female Guangling donkeys aged 24-36 months (average body weight 236.10 kg) were used as experimental animals. The shear force and intermuscular fat content of donkey meat were used as phenotypic data, phenotypic data was detected in 3 replicates per sample. In this study, based on the transcriptome and metabolome sequencing data of 14 longissimus dorsi muscle samples with significant shear force and intramuscular fat content differences in previous studies, WGCNA technology was used to screen genes and metabolites related to donkey meat tenderness, and combined transcriptome and metabolome analysis was performed to analyze tenderness related genes and metabolites. The results showed that 3 key gene modules Greenyellow, Darkgrey, Darkgreen and 2 key metabolite modules Brown and Yellow were obtained by using the WGCNA technology through|r| ≥ 0.5 and P ≤ 0.05. GO enrichment of key gene modules revealed that the genes in the modules were mainly enriched in GO functions such as glycerophospholipid biosynthesis, lipid oxidation, fatty acid β-oxidation, cellular macromolecular catabolism, muscle organ development, and calcium ion binding. KEGG functional enrichment analysis showed that most of genes and metabolites in the key modules were enriched in arginine and proline metabolism, Wnt signaling pathway, protein digestion and absorption, fatty acid metabolism, TCA cycle, glucagon signaling pathway, glycerophospholipid metabolism, purine metabolism, β-alanine metabolism and other pathways. Combined analysis indicated that alanine, aspartate and glutamate metabolism, arginine and proline metabolism, β-alanine metabolism and PPAR signaling pathway could regulate donkey meat tenderness. Alanine, aspartate and glutamate metabolism, arginine and proline metabolism, β-alanine metabolism and PPAR signaling pathway screened by WGCNA and combined KEGG co-enrichment analysis might play an important role in regulating donkey meat tenderness; while GAD1, PPAT, NIT2, AGMAT, CARNS1, ACOXL and adenylate succinic acid, L-proline, L-glutamic acid, creatine, homocarnosine, carnosine, pantothenic acid, (9S)-Hydroxy octadecadienoic acid might be the candidate genes and metabolites affecting donkey meat tenderness. This experiment results can provide a theoretical basis for the molecular regulation and improved breeding in meat tenderness of Guangling donkey in the future.

Key words: Guangling donkey, tenderness, WGCNA, omics, combined analysis