Abstract
Salivary cell secretion (SCS) plays a critical role in blood feeding by medicinal leeches, making them of use for certain medical purposes even today. To fill the gap in our knowledge about the genetically encoded components of leech SCS, we annotated the Hirudo medicinalis genome and performed RNA-seq on salivary cells isolated from three closely related leech species, H. medicinalis, Hirudo orientalis, and Hirudo verbana. Differential expression analysis verified by proteomics identified salivary cell-specific genes, many of which encode previously unknown salivary components. However, the genes encoding known anticoagulants were not differentially expressed in the salivary cells. The function-related analysis of the unique salivary cell genes enabled an update of the concept of interactions between salivary proteins and components of haemostasis. In addition, a metagenomic analysis performed in our study revealed the overall metabolic potential of the leech microbiota. Thus, our study extends the knowledge of the genetic fundamentals of the blood-sucking lifestyle in leeches.
