Genomic Analysis of Sphingopyxis sp. USTB-05 for Biodegrading Cyanobacterial Hepatotoxins

Abstract

Sphingopyxis sp. USTB-05, which we previously identified and examined, is a well-known bacterial strain for biodegrading cyanobacterial hepatotoxins of both nodularins (NODs) and microcystins (MCs). Although the pathways for biodegrading the different types of [D-Asp1] NOD, MC-YR, MC-LR and MC-RR by Sphingopyxis sp. USTB-05 were suggested, and several biodegradation genes were successfully cloned and expressed, the comprehensive genomic analysis of Sphingopyxis sp. USTB-05 was not reported. Here, based on second and third generation sequencing technology, we analyzed the whole genome of Sphingopyxis sp. USTB-05, which is 4,679,489 bp and contains 4,312 protein coding genes. There are 88 protein-coding genes related to the NODs and MCs biodegradation, of which 16 genes (bioA, hmgL, hypdh, speE, nspC, phy, spuC, murD, glsA, ansA, ocd, crnA, ald, gdhA, murC and murI) are unique. These genes for the transformation of phenylacetic acid CoA (PA-CoA) to CO2 were also found in Sphingopyxis sp. USTB-05. This study expands the understanding of the pathway for complete biodegradation of cyanobacterial hepatotoxins by Sphingopyxis sp. USTB-05.