Complete genome sequencing and analysis revealed the nitrogen utilization strategy of a novel Acuticoccus species isolated from surface water of the Indian Ocean

Abstract

Acuticoccus sp. I52.16.1 was isolated from 100 m water depth from the Indian Ocean, and presented a novel Acuticoccus species belonging to the family Acuticoccaceae, class Alphaproteobacteria. The strain I52.16.1 displayed the activities of nitrate reductase, nitrite reductase, and urease. The genome of Acuticoccus sp. I52.16.1 consisted of a circular chromosome (5, 134, 086 bp) with a G + C content of 69.7 mol%. The predicted number of coding genes was 4935, including 6 rRNA, 47 tRNA, and 2 sRNA. The 16S rDNA sequence displayed the maximum similarity of 97.58% with Acuticoccus yangtzensis JL1095^T, followed by Acuticoccus sediminis PTG4-2^T (97.05%), Acuticoccus kandeliae J103^T (96.52%), and Acuticoccus mangrove B2012^T (95.85%). Acuticoccus sp. I52.16.1 contained clades of genes involved in assimilating ammonium, nitrate, nitrite, and simple organic nitrogen compounds, but lacked the pathway for dissimilatory denitrification. Two distinct types of ureases were also detected, suggesting genetic heterogeneity. This study provided insight into the nitrogen metabolism strategies of heterotrophic bacteria in the oligotrophic ocean surface.