Hybrid Histidine Kinase WelA of sp. WG Contributes to WL Gum Biosynthesis and Motility.

sp. WG produced WL gum with commercial utility potential in many industries. A hybrid sensor histidine kinase/response regulator WelA was identified to regulate the WL gum biosynthesis, and its function was evaluated by gene deletion strategy. The WL gum production and broth viscosity of mutant Δ was only 44% and 0.6% of wild type strain at 72 h. The transcriptomic analysis of differentially expressed genes showed that WelA was mapped to CckA; ChpT, and CtrA in the CckA-ChpT-CtrA pathway was up-regulated. One phosphodiesterase was up-regulated by CtrA, and the intracellular c-di-GMP was decreased. Most genes involved in WL gum biosynthesis pathway was not significantly changed in Δ except the up-regulated and and the down-regulated . Furthermore, the up-regulated regulators , , and may participate in the regulation of flagellar biogenesis and influenced motility. These results suggested that CckA-ChpT-CtrA pathway and c-di-GMP were involved in WL gum biosynthesis regulation. This work provides useful information on the understanding of molecular mechanisms underlying WL gum biosynthesis regulation.