Azorhizobium caulinodans Chemotaxis Is Controlled by an Unusual Phosphorelay Network

doi:10.1128/jb.00527-21

	Azorhizobium caulinodans Chemotaxis Is Controlled by an Unusual Phosphorelay Network
	Kennedy, Emily N.1; Barr, Sarah A.1; Liu, Xiaolin 2,3; Vass, Luke R.1,5; Liu, Yanan 2,3; Xie, Zhihong 4; Bourret, Robert B.1
刊名	JOURNAL OF BACTERIOLOGY
	2022-02-01
卷号	204 期号:2 页码:23
关键词	Azorhizobium caulinodans chemotaxis phosphorelay phosphate sink
ISSN号	0021-9193
DOI	10.1128/jb.00527-21
通讯作者	Xie, Zhihong(zhxie@yic.ac.cn) ; Bourret, Robert B.(bourret@med.unc.edu)
英文摘要	Azorhizobium caulinodans is a nitrogen-fixing bacterium that forms root nodules on its host legume, Sesbania rostrata. This agriculturally significant symbiotic relationship is important in lowland rice cultivation and allows nitrogen fixation under flood conditions. Chemotaxis plays an important role in bacterial colonization of the rhizosphere. Plant roots release chemical compounds that are sensed by bacteria, triggering chemotaxis along a concentration gradient toward the roots. This gives motile bacteria a significant competitive advantage during root surface colonization. Although plant-associated bacterial genomes often encode multiple chemotaxis systems, A. caulinodans appears to encode only one. The che cluster on the A. caulinodans genome contains cheA, cheW, cheY2, cheB, and cheR. Two other chemotaxis genes, cheY1 and cheZ, are located independently from the che operon. Both CheY1 and CheY2 are involved in chemotaxis, with CheY1 being the predominant signaling protein. A. caulinodans CheA contains an unusual set of C-terminal domains: a CheW-like/receiver pair (termed W2-Rec) follows the more common single CheW-like domain. W2-Rec impacts both chemotaxis and CheA function. We found a preference for transfer of phosphoryl groups from CheA to CheY2, rather than to W2-Rec or CheY1, which appears to be involved in flagellar motor binding. Furthermore, we observed increased phosphoryl group stabilities on CheY1 compared to CheY2 and W2-Rec. Finally, CheZ enhanced dephosphorylation of CheY2 substantially more than CheY1 but had no effect on the dephosphorylation rate of W2-Rec. This network of phosphotransfer reactions highlights a previously uncharacterized scheme for regulation of chemotactic responses. IMPORTANCE Chemotaxis allows bacteria to move toward nutrients and away from toxins in their environment. Chemotactic movement provides a competitive advantage over nonspecific motion. CheY is an essential mediator of the chemotactic response, with phosphorylated and unphosphorylated forms of CheY differentially interacting with the flagellar motor to change swimming behavior. Previously established schemes of CheY dephosphorylation include action of a phosphatase and/or transfer of the phosphoryl group to another receiver domain that acts as a sink. Here, we propose that A. caulinodans uses a concerted mechanism in which the Hpt domain of CheA, CheY2, and CheZ function together as a dual sink system to rapidly reset chemotactic signaling. To the best of our knowledge, this mechanism is unlike any that have previously been evaluated. Chemotaxis systems that utilize both receiver and Hpt domains as phosphate sinks likely occur in other bacterial species.
WOS关键词	PROTEIN-SEQUENCE ANALYSES ; CHEY RESPONSE REGULATORS ; ESCHERICHIA-COLI CHEY ; KINETIC CHARACTERIZATION ; RHODOBACTER-SPHAEROIDES ; BACTERIAL CHEMOTAXIS ; HELICOBACTER-PYLORI ; FLAGELLAR ROTATION ; MYXOCOCCUS-XANTHUS ; DIFFERENT ROLES
WOS研究方向	Microbiology
语种	英语
WOS记录号	WOS:000765796700014
资助机构	National Institutes of Health ; National Natural Science Foundation of China
内容类型	期刊论文
源URL	[http://ir.yic.ac.cn/handle/133337/34790]
专题	中国科学院烟台海岸带研究所
通讯作者	Xie, Zhihong; Bourret, Robert B.
作者单位	1.Univ N Carolina, Dept Microbiol & Immunol, Chapel Hill, NC 27515 USA 2.Chinese Acad Sci, Yantai Inst Coastal Zone Res, Key Lab Coastal Environm Proc & Ecol Remediat, Yantai, Shandong, Peoples R China 3.Univ Chinese Acad Sci, Coll Resources & Environm, Beijing, Peoples R China 4.Shandong Agr Univ, Coll Recourses & Environm, Natl Engn Lab Efficient Utilizat Soil & Fertilize, Tai An, Shandong, Peoples R China 5.Univ Virginia, Dept Pathol, Charlottesville, VA 22903 USA
推荐引用方式 GB/T 7714	Kennedy, Emily N.,Barr, Sarah A.,Liu, Xiaolin,et al. Azorhizobium caulinodans Chemotaxis Is Controlled by an Unusual Phosphorelay Network[J]. JOURNAL OF BACTERIOLOGY,2022,204(2):23.
APA	Kennedy, Emily N..,Barr, Sarah A..,Liu, Xiaolin.,Vass, Luke R..,Liu, Yanan.,...&Bourret, Robert B..(2022).Azorhizobium caulinodans Chemotaxis Is Controlled by an Unusual Phosphorelay Network.JOURNAL OF BACTERIOLOGY,204(2),23.
MLA	Kennedy, Emily N.,et al."Azorhizobium caulinodans Chemotaxis Is Controlled by an Unusual Phosphorelay Network".JOURNAL OF BACTERIOLOGY 204.2(2022):23.