MOLECULAR DETECTION OF T4-like MYOVIRUSES IN HIGH MICROBIAL ABUNDANCE (HMA) MARINE SPONGES, Aaptos suberitoides AND Xestospongia testudinaria FROM TERENGGANU ISLANDS, MALAYSIA, SOUTH CHINA SEA

Sponges and viruses are abundant biotic components of the marine ecosystem, particularly when conducting nutrient recycling. Cyanobacteria are the main source of oxygen supplies and nutrient cycling and provide colouration to the sponge. Meanwhile, the T4-like phages are a group of lytic phages from Myoviridae known to infect cyanobacteria. These symbiotic relationships of sponges-cyanobacteria can be disrupted by the infection of cyanophages that can kill the cyanobacteria. Thus, this study aimed to detect the presence of T4-like myovirus in High Microbial Abundance (HMA) marine sponges such as Aaptos suberitoides and Xestospongia testudinaria from Bidong Island and Karah Island, Terengganu, Malaysia. A total of 208 replicates, sponges (n = 80), water (n = 64), and sponge mucus (n = 64) were subjected to Polymerase Chain Reaction (PCR) analyses accordingly. A total of four replicates of A. suberitoides (n = 4/15) from Karah Island and 26 replicates of water samples (n = 26/32) from Bidong Island (1X and 10X DNA dilution) demonstrated positive results. Sequencing analysis results of the Major Capsid Protein (MCP ) gene demonstrated 97.37% similarities for Bidong water samples and 77.72% similarities for sponge samples A. suberitoides for T4-like myovirus gene 23. Remarkably, this is the first detection of T4-like myovirus in both sponge species, A. suberitoides, X. testudinaria, and seawater in Malaysia.