[From SARS, MERS to COVID-19: A journey to understand bat coronaviruses].

From the beginning of this century, three coronaviruses (CoVs) have caused severe human respiratory diseases, including severe respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and corona virus disease 2019 (COVID-19), which outbroke in 2002-2003, 2012 and 2019-2020, respectively. These viruses are three different species belonging to  family,  genus. Discovery of closely-related CoVs in bats indicates that bats are natural reservoirs of these viruses. How and when the bat CoVs cross-species barriers to infect humans are largely understudied. This article provides an overview of the distribution, genetic evolution and interspecies transmission of bat coronaviruses in China, particularly focusing on bat SARS-related CoVs (SARSr-CoVs). Our studies showed that SARS-related CoVs are highly prevalent in horseshoe bats and some of them use the same receptor as SARS-CoV and SARS-CoV-2 and have wide cell tissue tropism. However, these bat viruses seem to be low pathogenic in human ACE2 transgenic mice compared with the SARS-CoV-2. These results imply that these bat CoVs have potential interspecies transmission to other animals and humans. Our work highlights the necessity of preparedness for future emerging infectious diseases caused by these CoVs.