Molecular mechanism of egg green shell trait formation based on transcriptomic and proteomics

【Objective】Study on potential regulatory genes and proteins involved in the formation of green shell eggs could provide a theoretical basis for the breeding of Chishui black-bone chicken and revealing the molecular mechanism of eggshell color formation in poultry. 【Method】Pure 280-day-old Chishui black-bone chicken was used as the research object. Collected gland tissue samples of dark green （SL） and white shell （BK） eggs， selected differential expressed genes （DEGs） and differentially expressed proteins （DEPs） through transcriptome sequencing and TMT quantitative proteomics technology， and combined analysis of the transcriptomics and proteomics were conducted， selected the candidate genes and candidate proteins regulating the color of green shell eggs. 【Result】A total of 82 DEGs were identified from the SL and BK groups through transcriptome sequencing， with 46 up-regulated and 36 down-regulated DEGs. Among these， four DEGs associated with eggshell pigment synthesis and deposition （SLC22A4， SPP1， FAM26E and HSP5 genes） were found to be up-regulated. KEGG signaling pathway analysis revealed significant enrichment of α-linolenic acid metabolism and arachidonic acid metabolism in the DEGs pathways. Additionally， a total of 167 DEPs were identified through TMT quantitative proteomics analysis， including 104 up-regulated and 63 down-regulated DEPs. KEGG signaling pathway enrichment analysis showed that the DEPs were mainly enriched in glycerophospholipid metabolism， cysteine and methionine metabolism， as well as ether lipid metabolism signaling pathways. Joint analysis of transcriptomics and proteomics indicated no common annotation of GO function terms between transcriptome and the proteome. However， 82 DEGs and 167 DEPs were enriched on 19 KEGG signaling pathways， among which two signaling pathways， glycerophospholipid metabolism and ether lipid metabolism， were found in both the transcriptome and proteome. 【Conclusion】 SLC22A4， SPP1， FAM26E and HSP5 genes and FAM102A， FAM107B and SLCO1B1 proteins may be involved in eggshell pigment synthesis， transport and deposition， especially the SLC family plays an important role， so it is speculated that these genes and proteins affect the formation of chicken egg candidate genes and proteins， and the enrichment of glycerophospholipid metabolism and ether lipid metabolism may be the key signaling pathway to regulate the formation of egg green shell.