NGS-BASED METAGENOMIC ANALYSIS OF MICROBIAL COMMUNITIES FROM THE RED SEA: ASSEMBLY, GENE PREDICTION, AND FUNCTIONAL ANNOTATION

Abstract

The Red Sea is far less studied than other major oceans, despite its remarkable marine productivity. Microbiology and associated technologies have emerged as the principal areas of study in the Red Sea following extensive degradation of marine ecosystems and the overexploitation of marine resources. In this investigation, whole-genome shotgun sequencing was conducted on five samples collected from different depths in the Red Sea. Samples were taken from the Jeddah beach at 21o45'23.1 N and 39o03'38.8" E. They were then taken down to depths of 10, 15, 20, 25, and 30 meters. This study's comprehensive functional and diversity analyses provide strong evidence that group identification plays a significant role in determining the structure and function of microbial communities.  CAZy analysis showed that the GT2 family was the most abundant across all samples, with 2,412 in R1, 2,511 in R2, 1,973 in R3, 2,658 in R4, and 2,390 in R5 samples. Hierarchical clustering based on Bray–Curtis distance, coupled with stacked bar charts of relative abundance for PHI-base annotations, revealed that the highest relative abundance was associated with Pseudomonas aeruginosa, particularly in the R3 sample. This was followed by Salmonella enterica at PHI level 2 and the virulence-associated gene RhIE1 (PA3950) at PHI level 3. P. aeruginosa is commonly detected in coastal marine environments and was shown to release OprP, as supported by immunochemical analysis of saltwater samples. The only bacterium consistently detected across all samples was Vibrio ponticus. Notably, the R3 sample was distinct, exhibiting the highest abundance of Vibrio chagasii and Vibrio sp. AND4. Overall, our results indicate that all samples originated from a Vibrio-rich environment, consistent with aquatic habitats where Vibrio species are known to form symbiotic or pathogenic associations with their hosts.