Comparative Transcriptome Analysis Of Bat Species Representative Of The Genus Rhinolophus In China

Horseshoe bats are considered to be the potential reservoir hosts of the severe acute respiratory syndrome coronavirus(SARS-CoV)and severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).This bat genus can carry these viruses asymptomatically despite the fact that they have been responsible for widespread host transmission and mortality in humans and other mammals.Horseshoe bats have a variety of extraordinary adaptive traits present in other bat species of the order Chiroptera,such as the fly ability,exceptional lifespan,enhanced disease tolerance,and a unique immune system,this has sparked a lot of interest in bat research.However,it still remains unclear that how bats coexist with pathogens and adapt to diverse extreme environments.We sequenced,assembled,and analyzed the whole transcriptomes of 12 bat species representative of the Rhinolophus genus in China,to identify the molecular basis for transcriptional level differences and specific adaptive evolutionary traits in human and healthy Rhinolophus bats found in this bat genus.On the one hand,we detected numerous infection and cancer-related pathways,based on the functional annotation of differentially expressed genes in bats and humans from multiple organs.It was suggested that bats might exist a specific antiviral response immune system that allows them to sustain a balance between host defence and immune tolerance due to their massive downregulated innate immune-related genes(IRGs)when compared with functional counterparts in human.The discovery of these differentially expressed IRGs supports the hypothesis that bats have an inhibitory immune state,but the function of these IRGs requires further research.On the other hand,to investigate the characteristics of the bat transcriptome above the evolutionary level,146 genes were found under positive natural selection based on the holistic analysis of positive selection for bats transcriptomes.By annotating each of these genes,we found that most of them are involved in immune response and cancer suppression,which is in convergence with the findings of differential expression analysis.This transcriptome analysis sheds light on the molecular basis of the unique antiviral immune response and antitumor defense of the host defense system in Rhinolophus bats.This study provides a rich source of data on the adaptive mechanisms of the Rhinolophus bats,and these conclusions and findings also provide new ideas and strategies for the prevention and treatment of infectious diseases.In addition,a large number of promising candidate genes are expected to become molecular targets for the eventual prevention,control and treatment of human infectious diseases,cancer and other related diseases.