Genomic Characterization Of Vibrio Campbellii Rt 1 And Vibrio Harveyi Rt 6 Strains Isolated From Infected Shrimp Litopenaeus Vannamei

Abstract

Vibrio spp. belonging to Vibrionaceae family exists as natural microbial flora of wild and cultured shrimps. The pathogenicity of quotVibriosisquot in shrimps constitutes a major obstacle to the sustainable development of mariculture. However, Vibriosis infection provoked by this pathogenic community targets larvae and juvenile stages of rearing shrimps leading to adverse mortality and tremendous economic losses. The outbreak of the disease is predominantly associated with Vibrio harveyi and its closely related species. Furthermore, genomic technologies are designed to study the specific organisms, genome architecture, genome evolution, organization, expression and function of selected modified genomes of interest in order to maximize benefits for better understanding of pathogenicity. This thesis provides a detailed investigation to identify bacterial isolates in infected shrimps (Litopenaeus vannamei) from aquaculture ponds located in Marakkanam, East coast of Chennai, Tamil Nadu, India (12.1899° N, newline79.9249° E). Notably, six pathogenic species: - V. harveyi (MH209255); V. campbellii (MH211225); V. parahaemolyticus (MH211224); V. owensii (MH211364); V. rotiferianus (MH211221) and V. alginolyticus (MH209576) were isolated from infected shrimps inhabiting the ponds. Among them, V. campbellii and V. harveyi were identified as major etiological agents contributing to mass mortality of shrimps. newline newline newlineThis doctoral thesis provides sequencing the whole genome of Vibrio campbellii RT-1 and Vibrio harveyi RT-6 strains. The whole genome sequencing (WGS) was performed using the Illumina Hiseq 2500 platform and assembled de novo using SPAdes and Velvet optimiser. Furthermore, genome annotation can be divided into two different phases: gene prediction and functional annotation which were performed by a rapid prokaryotic genome tool-Prokka. The genome of V. campbellii RT-1 strain possesses the genome size with 6,327,218 bp. V. campbellii RT-1 strain contains 5,787 predicted genes with an average of 45% G