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

Abstract

AbstractWolbachiais a genus of maternally inherited endosymbionts that can affect reproduction of their hosts and influence metabolic processes. The pollinator,Valisia javana, is common in the male syconium of the dioecious figFicus hirta. Based on a high-quality chromosome-levelV. javanagenome with PacBio long-read and Illumina short-read sequencing, we discovered a sizeable proportion ofWolbachiasequences and used these to assemble two novelWolbachiastrains belonging to supergroup A. We explored its phylogenetic relationship with describedWolbachiastrains based on MLST sequences and the possibility of induction of CI (cytoplasmic incompatibility) in this strain by examining the presence ofcifgenes known to be responsible for CI in other insects. We also identified mobile genetic elements including prophages and insertion sequences, genes related to biotin synthesis and metabolism. A total of two prophages and 256 insertion sequences were found. The prophage WOjav1 is cryptic (structure incomplete) and WOjav2 is relatively intact. IS5 is the dominant transposon family. At least three pairs of type Icifgenes with three copies were found which may cause strong CI although this needs experimental verification; we also considered possible nutritional effects of theWolbachiaby identifying genes related to biotin production, absorption and metabolism. This study provides a resource for further studies ofWolbachia-pollinator-host plant interactions.