[Chemotaxis and characteristics of chemotactic genes in Novosphingobium strains]

The present study aims to analyze the chemotaxis genes and proteins of several PAH-degrading Novosphingobium strains, and the chemotaxis of these strains toward aromatic compounds and intermediates.

Based on genome comparative analysis, we identified the chemotaxis genes organization and proteins distribution. We used drop and swarm plate assays to detect the chemotaxis of these strains toward aromatic compounds and intermediates of TCA cycle.

We found that all these Novosphingobium strains showed chemotaxis, but the chemotatic ability varied. The completed genome sequenced strains N. pentaromativorans F2, N. pentaromativorans US6-1, N. pentaromativorans PP1Y, Novosphingobium sp. AP12, Novosphingobium sp. Rr 2-17, and Novosphingobium nitrogenifigens DSM 19370 contained MCP, CheW, CheA, CheB, CheR and CheY. Strain F2, US6-1 and PP1Y, shared a consistent order of chemotaxis genes in "che" cluster. The chemotatic system of these Novosphingobium strains belonged to the Fla chemotactic system.

These strains all contained a complete chmotaxis pathway. Their chemotactic ability toward aromatic compounds and intermediates varied, and the chemotaxis of US6-1 was obvious.