Meta-transcriptional Detection of Rickettsia canadensis from Ixodes persulcatus in China

Abstract

Abstract Genus Rickettsia associated to blood-feeding arthropods are usually pathogenic when transmitted to vertebrates. These species include the agents of acute human disease such as typhus and Rocky Mountain spotted fever. However, many other Rickettsia have been uncovered with uncertain pathogenic to vertebrates in recent surveys. It is therefore perhaps more appropriate to consider these Rickettsiaas endosymbionts that are transmitted vertically in invertebrates, and secondarily as pathogens of vertebrates. Rickettsia canadensis, an ancestor species in genus Rickettsia, had been well characterized for its peculiar genome size and genes’ contents bridging the pathogenic Rickettsiaand non-pathogenic ones. However, there is few research on the ancient rickettsia species in China which may seriously influence our pursue for the evolutionary nature of Rickettsia in China. In the present study, R. canadensis was detected from Ixodes persulcatusticks from forest areas of both Heilongjiang province and Inner Mongolia Autonomous Region in northern China. The molecular evidences from both 16S rRNA gene and 3 arrays of gene transcripts strongly indicated the natural infection of R. canadensis occurs in Ixodid ticks in China. The gene transcripts including rpoB-rpoC-rpoC/160KDa-leucyl aminopeptidase-hypothetical protein-leucyl aminopeptidase-aspartate tRNA ligase, RlmE-Omp 1-Peptidase M50-nusB, dnaK-dnaJ-ChaBfamily protein-BamD-RecN-Carboxypeptidase M32 revealed from I. persulcatus suggested the intensive interactions between R. canadensis and. host ticks, which would provide scientific clues to highlight the possible evolutionary trajectory of Rickettsia species in China.