Acetylcholine chemotaxis in global bacterial plant pathogens

Area of Science:

• Microbiology
• Plant Pathology
• Biochemistry

Background:

• Plant-microbe interactions involve diverse signaling molecules.
• Chemotaxis enables bacteria to navigate chemical gradients for plant colonization.
• Acetylcholine, a known neurotransmitter, also regulates plant processes.

Purpose of the Study:

• Investigate bacterial chemotaxis towards acetylcholine.
• Identify the chemoreceptors and molecular mechanisms involved.
• Determine the functional significance of acetylcholine sensing in plant pathogens.

Main Methods:

• Bacterial chemotaxis assays.
• Identification and characterization of chemoreceptors (AtuA, MkcA, DdaA).
• Structural analysis of chemoreceptor-ligand complexes (MkcA-LBD with choline).
• In planta colonization assays.

Main Results:

• Agrobacterium and Dickeya species exhibit strong chemotaxis to acetylcholine.
• Specific dCache_1-type chemoreceptors mediate these responses.
• Chemoreceptors recognize acetylcholine and other quaternary amines with varying affinities.
• Acetylcholine provides osmoprotective effects and nutritional benefits for some species.

Conclusions:

• Acetylcholine is a key signal molecule for plant pathogenic bacteria.
• Chemosensory systems for acetylcholine are crucial for plant infection and stress adaptation.
• Findings suggest co-evolutionary relationships between plants and their associated microbes.