Single-cell transcriptome sequencing reveals Wolbachia -mediated modification in early stages of Drosophila spermatogenesis

Abstract

Wolbachia are the most widely distributed intracellular bacteria, and their most common effect on host phenotype is cytoplasmic incompatibility (CI). A variety of models have been proposed to decipher the molecular mechanism of CI, among which the host modification (HM) model predicts that Wolbachia effectors play an important role in sperm modification. However, owing to the complexity of spermatogenesis and testicular cell-type heterogeneity, whether Wolbachia have different effects on cells at different stages of spermatogenesis or whether these effects are linked with CI remains unknown. Therefore, we used single-cell RNA sequencing to analyse gene expression profiles in adult male Drosophila testes that were infected or uninfected by Wolbachia . We found that Wolbachia significantly affected the proportion of different types of germ cells and affected multiple metabolic pathways in germ cells. Most importantly, Wolbachia had the greatest impact on germline stem cells, resulting in dysregulated expression of genes related to DNA compaction, and Wolbachia infection also influenced the histone-to-protamine transition in the late stage of sperm development. These results support the HM model and suggest that future studies on Wolbachia -induced CI should focus on cells in the early stages of spermatogenesis.

Prophage proteins alter long noncoding RNA and DNA of developing sperm to induce a paternal-effect lethality

“…Both CifA and CifB localize to spermatogonia and spermatocyte nuclei ( 13 ); thus, it is possible that Cifs act on AAGAG lncRNA and perhaps other spermatogenesis-related lncRNAs ( 24 , 26 ) earlier during premeiotic spermatogenesis to prime cells and/or chromosomes to affect downstream postmeiotic sperm chromatin organization. These findings are consistent with single-cell transcriptome sequencing in which Wolbachia alter fly gene expression in early stages of spermatogenesis, leading to downstream sperm defects ( 27 ). Altogether, the role of CifA in depleting AAGAG lncRNA suggests that CifA RNase activity is central to establishing the CI modification during early sperm development.…”

Insect Insights at the Single-Cell Level: Technologies and Applications

“…Interestingly, this technology has been used not only for the model insect Drosophila , but also for other insects, and numerous insect organs have been studied ( Figure 2 , Table 1 ). Recently, researchers have provided in-depth insights into the mechanisms governing embryonic development [ 47 , 48 ], germ cell development [ 44 , 45 , 49 , 50 ], brain aging [ 51 ], intestinal stem cell differentiation [ 52 ], tumorigenesis [ 53 , 54 ], immune cell specification [ 55 , 56 ], and neural development [ 57 , 58 , 59 ] of insects, using advanced techniques such as scRNA-seq In addition, scientists have used scRNA-seq to compare different caste members in social insects, unravelling the mysteries of their evolution [ 60 , 61 , 62 ].…”

“…Recent research of Witt et al [ 96 ] which compared early germ cells from old and young flies further characterized late spermatogenesis as a source of evolutionary innovation. scRNA-seq was also employed to uncover the of biotic ( Wolbachia ) and abiotic (Antimony) effects on the testis at single-cell level, including changes of the proportion of different types of germ cells and multiple metabolic pathways in germ cells [ 44 , 50 ].…”