Study On Cold Resistance Mechanism Of Mongolian Cattle Based On Transcriptome

Mongolian cattle is one of characteristic species of Mongolian plateau,After a long period of adaptive selection for a harsh natural environment,it has evolved a strong biological characteristics of cold resistance.In this study,skin,fat,muscle and liver tissues of Mongolian cattle in winter and summer were RNA-sequenced and bioinformatics analysed to reveal the regulation patterns of different tissues during cold resistance,and to screen out the candidate genes and signaling pathways,and lay the foundation for the cold resistance mechanism researches of herbivores.The specific results of this study are as follows:1.Differential expression analysis showed that the numbers of DEGs in the skin,fat,muscle and liver tissues were 182,2100,128 and 89,respectively.2.Clustering analysis of DEGs showed that different tissues of Mongolian cattle had different gene expression patterns.Different tissues played different roles in the process of cold resistance.These tissues were independent and had their own regulatory mechanism3.GO analysis showed that lipid synthesis and transport,as well as the regulation of enzyme activity which is enriched in the skin tissues,nerve regulation and cell signal transduction which is enriched in the adipose tissue,cell signal transduction in muscle may be related to cold resistance of Mongolian cattle;4.KEGG analysis showed that there were 23 signaling pathways enriched in skin,in which the metabolic pathways associated with lipid transport and metabolism and melanin synthesis may be important for cold resistance of Mongolian cattle;DEG_s of adipose tissue were enriched into 41 signaling pathways,including circadian entrainment,steroid biosynthesis,PPAR signaling pathway.They may be involved in the Mongolian cattle cold resistance process through the regulation of lipid metabolism.5.Hub gene network analysis showed that RARRES1 is a pivotal gene,which may play an important role in regulating adipose tissue and adipocytes development in winter.6.Candidate gene screening results showed that there were 4,21,2 and 2candidate genes screened out from skin,fat,muscle and liver tissues,respectively.7.The results showed that the roles and metabolic pathways of the skin,adipose,muscle and liver tissues of Mongolian cattle during cold resistance were all different,and it showed tissue independence.Skin tissue may reduce oxidative stress which is caused by cold resistance primarily by lowering ROS levels and may reduce the heat loss by increasing hair thickness through making hair more crimped;Adipose tissue may reduce cholesterol biosynthesis and reduce adipocytes FA uptake,to maintain cell membrane fluidity and to maintain FFA in the blood at a high level,in order to provide energy for other tissues;Unlike short-term strategies for cold adaptation in other mammalian,Mongolian cattle muscle tissue does not depend on increasing the skeletal muscle heat production,and may depend on reducing the energy comsuption by reducing exercise performance;Liver tissue protects itself by inhibiting synthesis of hepatic fat while maintaining high levels of FFA in the circulatory system in order to provide metabolic substrates for other tissues to withstand coldness.It was the first time that the cold resistance mechanism of Mongolian cattle was described at the transcriptional level.Numbers of candidate genes and pathways were found.This study will provided references for herbivores'cold tolerance mechanisms researches.