Gut microbial restructuring in white spot syndrome virus-infected Penaeus vannamei: Insights from long-read...

Microbial community restructuring following White Spot Syndrome Virus (WSSV) infection is a critical determinant in modulating the disease progression in Penaeus vannamei. In this study, full-length 16S rRNA sequencing (V1-V9) was employed to delineate the microbial shifts in healthy and WSSV-infected shrimp. The analysis revealed a pronounced reduction in Firmicutes in the WSSV-infected shrimp, a dysbiosis signature reported in WSSV-associated amplicon studies. With the advantage of full-length sequencing, this study achieved species-level resolution, identifying Vibrio alginolyticus (a known pathogen) alongside putative beneficial taxa such as Ruegeria conchae, R. arenilitoris, Demequina litorisediminis, and D.globuliformis, which were not captured in earlier amplicon-based studies. Diversity analysis demonstrated that, rather than loss of species, substantial restructuring in the form of abundance was observed between healthy and WSSV-infected shrimp, while the overall evenness of the community remained stable. Concurrently, WSSV-infection has triggered an increased abundance of core opportunistic pathogens, namely, Photobacterium damselae and V. alginolyticus, which clustered distinctly from putative beneficial taxa such as Ruegeria and Demequina species, reflecting a clear microbial imbalance. Collectively, these findings demonstrated that mortality in WSSV-infected shrimp is associated with dysbiosis characterized by a depletion of beneficial taxa and concomitant abundance of opportunistic pathogens. These insights provide a basis for developing targeted probiotic or therapeutic strategies to mitigate pathogen overgrowth.