Investigating genetic markers and key genes associated with sheep growth rate using integrated multi-omics approaches could provide valuable insights for the sheep industry. Based on the average daily gain (ADG), fast-growing (N_case=70) and slow-growing (N_control=70) Hu sheep were selected for a genome-wide association study (GWAS). Ten Hu sheep (fast-growing, n=5; slow-growing, n=5) and ten Dorper sheep (fast-growing, n=5; slow-growing, n=5) were selected for comparative transcriptome analysis. We identified hub genes and tissue-specific genes (TSGs) using weighted gene co-expression network analysis (WGCNA) and RNA sequencing (RNA-Seq) data from ten tissues, respectively. Ten genes were found within 50 kb distances of the significant single nucleotide polymorphisms (SNPs). Based on a comparative transcriptomic analysis, a total of 501 and 441 differentially expressed genes (DEGs) were identified in the HF vs. HS and DF vs. DS comparisons, respectively. We found some important signaling pathways closely associated with fat metabolism and energy metabolism, such as “regulation of lipolysis in adipocytes”, “Oxidative phosphorylation”, and “Thermogenesis”. Several DEGs play a crucial role in fat deposition (such as ADRB3, PDE3B, FABP4, SERPINE1, PLIN1, and FOXO6) and muscle development (MYL3). Using the WGCNA analysis, 15 genes were considered as hub genes associated with ADG. Integration of GWAS and RNA-Seq data indicates that BRINP3 and PENK may further influence the growth rate by regulating feeding behavior in sheep. Association analysis of 1,071 Hu sheep populations revealed that mutations in the BRINP3 (BRINP3 g.16903465 T>C) and PENK (PENK g.39289926 T>C) genes were significantly related to the growth traits (P<0.05). Our research provides novel insights into understanding the molecular mechanisms underlying growth traits in sheep. BRINP3 and PENK genes may be potential key candidate genes related to sheep growth rate.

Kiwifruit bacterial canker, caused by Pseudomonas syringae pv. actinidiae (Psa), is a significant threat to the kiwifruit industry. The two-component signaling systems (TCSs) play a crucial role in regulating the virulence of Pseudomonas syringae (P. syringae), yet their specific function in Psa remains largely unclear. In this study, we found that disrupting the TCS RegAB (encoded by Psa_802/Psa_803) resulted in a notable increase in the pathogenicity of Pseudomonas syringae pv. actinidiae M228 (Psa M228) in host plant and hypersensitive reaction (HR) in nonhost plant. Through comparative transcriptome analysis of the Psa M228 wild-type strain and the regA mutant, we identified the pivotal role of RegA/B in controlling various physiological pathways, including the Type III secretion system (T3SS), a key determinant of Psa virulence. Additionally, we discovered that the RegA does have binding sites in the promoter region of the hrpR/S, and the transcriptional level of the hrpR and other T3SS-related genes increased in the regA deletion strain relative to the Psa M228 wild-type. The DNA-binding affinity of RegA, and therefore the repressor function, is enhanced by its phosphorylation. Our findings unveil the function of TCS RegAB and the regulatory mechanism of T3SS by RegAB in Psa, highlighting the diverse functions of the RegAB system.