Ecology and host-symbiont interactions drives the strain-specific association of Wolbachia with Indian Drosophila host

The discovery of Wolbachia, a gender bender of insect population revolutionized the field of medical biology with the possibility of using Wolbachia infected host to control the spread of major vector borne diseases. Drosophila has long been known as an invertebrate experimental model and the presence of Wolbachia strains in this species makes it unique for the entomologist to explore the different Wolbachia strains present in the Drosophila host and understand host-symbiont interactions. In the light of these developments we obtained whole genome sequences of four different Wolbachia strains using NGS technology based on Illumina platform isolated from two human commensal Indian Drosophila species i.e. Drosophila melanogaster and Drosophila ananassae from Kochi (Southern India) and Ahmedabad (Western India). The strains were identified as wMel to be present in D. Melanogaster and wRi in D. Ananassae based on BLAST analysis. This was the first attempt at obtaining the whole genomes of Indian Wolbachia strains. Further we compared these novel genome assemblies and observed strain-specific sequence similarity in certain gene sequences known for their significant role in strain identification or host symbiont interaction. Upon comparison of the Indian Wolbachia genomes with the earlier sequences one, we also observed India specific sequence similarity in some of the genes. In order to understand better the Wolbachia-host association we also studied the associated bacterial diversity in these two Drosophila species. The distribution of the associated bacterial species was found to be both species as well region dependent. The findings of the current study support that ecology also plays a major role in gene-genome evolution and host preferences. The results of the above study provide us an overview of Wolbachia-host interaction and strain specific nature of this endosymbiont. However, in order to further understand the exact forces at play that makes such an association, deeper study needs to be carried out