Microbiome analysis of gut bacterial communities of healthy and diseased Malaysian mahseer (Tor tambroides) using 16S rRNA metagenomics approach

Aims@#The gut microbiota is referred to as an ‘extra organ’ and is critical in assisting the host in terms of nutrition and immunity. Environmental stressors could alter the gut microbial community and cause gut inflammation. This study aimed to investigate and compare the gut microbiota community between healthy and diseased Tor tambroides.@*Methodology and results@#In this study, such gut microbial alterations were explored using NGS-based 16S rDNA targeted sequencing on the Malaysian mahseer (T. tambroides). Three healthy adult and three diseased adult Malaysian mahseers (showing signs of exophthalmia, coelomic distension and petechial haemorrhage) were obtained from LTT Aquaculture Sdn Bhd. Our results revealed significant differences in microbial diversity, composition and function between both populations of T. tambroides. Alpha diversity analysis depicts lower diversity of gut microbiota composition in diseased T. tambroides as compared to the healthy group. In particular, Enterobacteriaceae, Aeromonas, Bacteroides, Vibrio and Pseudomonas were found within gut microbiota of the diseased fishes. In addition, cellulosedegrading bacteria and protease-producing bacteria were identified from the gut of T. tambroides.@*Conclusion, significance and impact of study@#Thus, our findings emphasized on the association between the alteration in gut microbiota composition and infectious abdominal dropsy (IAD) in T. tambroides. This finding is important to provide basic information for further diagnosis, prevention and treatment of intestinal diseases in fish.

Cucumber mosaic virus: Global genome comparison and beyond

Aims@#The cucumber mosaic virus (CMV) is categorized under the genus Cucumovirus and family Bromoviridae. This virus is known to infect over 1200 plant species from 100 families, including ornamental and horticultural plants. In this study, we pioneered a global genome comparison to decipher the unknown orchestrators behind the virulence and pathogenicity of CMV via the discovery of important single nucleotide polymorphic markers.@*Methodology and results@#As a result, the genome size was found to be a potential preliminary country-specific marker for South Korea and the GC content can be utilized to preliminarily differentiate Turkey isolates from the others. The motif analysis as well as whole genome and coat protein phylogenetic trees were unable to form country-specific clusters. However, the coat protein haplotype analysis had successfully unconcealed country-specific single nucleotide polymorphic markers for Iran, Turkey and Japan isolates. Moreover, coat protein modelling and gene ontology prediction depicted high conservation across CMV isolates from different countries.@*Conclusion, significance and impact of study@#The country-specific single nucleotide polymorphic markers unearthed in this study may provide significant data towards the profiling of varying virulence and pathogenicity of CMV across the globe in time to combat the yield loss driven by this virus thru the most efficacious biological control measures in the future.