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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Emerging Pests and Pathogens Research » Research » Publications at this Location » Publication #421269

Research Project: Advancing Knowledge of the Biology and Etiology of Bacterial Plant Pathogens Towards Management Strategies

Location: Emerging Pests and Pathogens Research

Title: Genome-wide identification of novel flagellar motility genes in Pseudomonas syringae pv. tomato DC3000

Author
item YANG, ZICHU - Cornell University
item Helmann, Tyler
item BAUDIN, MAEL - University Of California Berkeley
item SCHREIBER, KARL - University Of California Berkeley
item Bao, Zhongmeng
item Stodghill, Paul
item DEUTSCHBAUER, ADAM - University Of California Berkeley
item Lewis, Jennifer
item Swingle, Bryan

Submitted to: mBio
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Bacterial motility serves various ecological functions including accessing nutrients, social interactions as well as virulence in pathogenic species. Motility is a complex process and the bacterial genes involved in motility are largely uncharacterized. Here we used a very large genetic screen and in vitro selection to identify novel genes that contribute to motility in Pseudomonas syringae, an important plant pathogenic bacterium. This approach allowed us to identify the set of genes that Pseudomonas syringae needs to move and other genes important for bacterial survival. Our results provide valuable resources for our future research and information about the underlying genetics, molecular mechanisms, and ecological implications of bacterial motility, advancing both fundamental microbiology and applied biomedical research.

Technical Abstract: Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) is a plant pathogenic bacterium that possesses complicated motility regulation pathways including a typical chemotaxis system. A significant portion of our understanding about the genes functioning in Pst DC3000 motility is based on comparison to other bacteria. This leaves uncertainty about whether gene functions are conserved, especially since specific regulatory modules can have opposite functions in sets of Pseudomonas. In this study, we used a competitive selection to enrich for mutants with altered swimming motility and used random barcode transposon-site sequencing (RB-TnSeq) to identify genes with significant roles in swimming motility. Besides many of the known or predicted chemotaxis and motility genes, our method identified PSPTO_1042 (chrR) and PSPTO_4229 (hypothetical protein) as novel motility regulators. PSPTO_1042 is part of an extracytoplasmic sensing system that controls gene expression in response to reactive oxygen species, suggesting that PSPTO_1042 may function as part of a mechanism that enables Pst DC3000 to alter motility when encountering oxidative stressors. PSPTO_4229 encodes a protein containing an HDOD motif, but with no previously identified functions. We found that deletion and overexpression of PSPTO_4229 both reduce swimming motility, suggesting that its function is sensitive to expression level. We used the overexpression phenotype to screen for nonsense and missense mutants of PSPTO_4229 that no longer reduce swimming motility and found a pair of conserved arginine residues that are necessary for motility suppression. Together these results provide a global perspective on regulatory and structural genes controlling flagellar motility in Pst DC3000.