AUTHOR=Li Hui , Chen Mengqi , Zhang Zaimei , Li Benchao , Liu Jianlin , Xue Han , Ji Sixue , Guo Zhongrui , Wang Jiqian , Zhu Hu 

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

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.792315

DOI=10.3389/fmicb.2022.792315

ISSN=1664-302X

ABSTRACT=<p><italic>Sphingomonas</italic> 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<italic>welA</italic> 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<italic>welA</italic> except the up-regulated <italic>atrB</italic> and <italic>atrD</italic> and the down-regulated <italic>pmm</italic>. Furthermore, the up-regulated regulators <italic>ctrA, flaEY</italic>, <italic>flbD</italic>, and <italic>flaF</italic> 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.</p>