Actinobacteria diversity associated with sponge Amorphinopsis exacavans from Rancabuaya Beach, Garut, Indonesia

Abstract

Sponges are complex marine organisms known for their symbiotic relationships with various bacterial communities, which play structural and functional roles within the sponge holobiont. Actinobacteria have received much attention because of their potential pharmaceutical applications. This study examines Amorphinopsis excavans profile, distinguishing between endosymbionts and ectosymbionts. The microbial grouping was characterized using Next Generation Sequencing (NGS) anchored to the 16S rRNA marker. The results showed that Proteobacteria and Firmicutes dominated both the endosymbiont and ectosymbiont communities at the phylum level. The actinobacterial diversity index at the genus level in both communities was 2.77 and 3.11, indicating moderate to high diversity without a dominant genus. For the genus level, the evenness scores of 0.81 and 0.89 indicated a high population type within the bacterial community. Relative abundance revealed the three most prevalent genera in the endosymbiont community were Rothia, Thermoplyspora, and Thermomonospora. In contrast, Kocuria, Mycobacterium, and Bifidobacterium were the three most common genera of ectosymbionts. Leuconostoc citreum was the first species known to be associated with a sponge. This study is a developing metagenomic assessment of actinobacterial diversity in A. excavans, providing novel insights into the sponge's complex microbial ecosystem.