Evolution of Wolbachia reproductive and nutritional mutualism: insight from two novel strains that double infect pollinator of dioecious Ficus hirta

Wolbachia is a genus of endosymbiont which can manipulate the reproductive system of hosts and exert an influence on metabolic processes. Wolbachia is dominant in male syconium of dioecious Ficus hirta with pollinator Valisia javana . From high-quality chromosome-level V. javana genome with PacBio long-read and Illumina short read sequencing, we discovered a sizeable proportion of Wolbachia sequences and then assembled two novel strains belonging to supergroup A. Besides the basic genome description, we identified mobile genetic elements including prophages and insertion sequences, genes related to biotin synthesis and metabolism, and cytoplasmic incompatibility related cif genes in them. The results showed that (i) A total of two prophages and 201 insertion sequences were found. The prophage WOjav1 is cryptic and WOjav2 relatively intact. IS5 is dominant family. (ii) At least three pairs of cif genes belong to type I and is speculated to cause strong CI with infected female biased reproductive advantages; (iii) The Wolbachia only provide biotin precursors to absorb and metabolize biotin which is synthesized by host plant. This research provided a basis for reproductive and nutritional mutualism between Wolbachia and fig-fig wasp system, and will serve as a useful resource for further research into Wolbachia -pollinator-host interactions.