RT Journal Article SR Electronic T1 A single-cell survey of Drosophila blood JF bioRxiv FD Cold Spring Harbor Laboratory SP 2019.12.20.884999 DO 10.1101/2019.12.20.884999 A1 Sudhir Gopal Tattikota A1 Yanhui Hu A1 Yifang Liu A1 Bumsik Cho A1 Victor Barrera A1 Michael Steinbaugh A1 Sang-Ho Yoon A1 Aram Comjean A1 Fangge Li A1 Franz Dervis A1 Ruei-Jiun Hung A1 Jin-Wu Nam A1 Shannan Ho Sui A1 Jiwon Shim A1 Norbert Perrimon YR 2019 UL http://biorxiv.org/content/early/2019/12/30/2019.12.20.884999.abstract AB Drosophila blood cells, called hemocytes, are classified into plasmatocytes, crystal cells, and lamellocytes based on the expression of a few marker genes and cell morphologies, which are inadequate to classify the complete hemocyte repertoire. Here, we used single-cell RNA sequencing (scRNA-seq) to map hemocytes across different inflammatory conditions in larvae. We resolved plasmatocytes into different states based on the expression of genes involved in cell cycle, antimicrobial response, and metabolism together with the identification of intermediate states. Further, we discovered rare subsets within crystal cells and lamellocytes that express fibroblast growth factor (FGF) ligand branchless and receptor breathless, respectively. We demonstrate that these FGF components are required for mediating effective immune responses against parasitoid wasp eggs, highlighting a novel role for FGF signaling in inter-hemocyte crosstalk. Our scRNA-seq analysis reveals the diversity of hemocytes and provides a rich resource of gene expression profiles for a systems-level understanding of their functions.HighlightsscRNA-seq of Drosophila blood recovers plasmatocytes, crystal cells, and lamellocytesscRNA-seq identifies different plasmatocyte states based on the expression of genes involved in cell cycle regulation, antimicrobial response, and metabolismPseudotemporal ordering of single cells identifies crystal cell and lamellocyte intermediate statesscRNA-seq uncovers a novel role for FGF signaling in inter-hemocyte crosstalk