Wolbachiainfection at least partially rescues the fertility and ovary defects of several newDrosophila melanogaster bag of marblesprotein-coding mutants

Abstract

The D. melanogaster protein coding gene bag of marbles (bam) plays a key role in early male and female reproduction by forming complexes with partner proteins to promote differentiation in gametogenesis. Like another germline gene, Sex lethal, bam genetically interacts with the endosymbiont Wolbachia, as Wolbachia rescues the reduced fertility of a bam hypomorphic mutant. Here, we explored the specificity of the bam-Wolbachia interaction by generating 22 new bam mutants. We find Wolbachia rescues all six mutants of partially reduced fertility, but none of the four with severely reduced fertility. There is no specificity between the rescue and the known binding regions of bam, suggesting Wolbachia does not interact with one singular bam partner to rescue fertility. We further tested if Wolbachia interacts with bam in a non-specific way, by increasing bam levels or acting upstream in germline stem cells. However, a fertility assessment of a bam RNAi knockdown mutant reveals that Wolbachia rescue is specific to functionally mutant bam alleles and we find no obvious evidence of Wolbachia interaction with germline stem cells in bam mutants.