Contact-dependent traits in Pseudomonas syringae B728a

Area of Science:

• Microbiology
• Molecular Biology
• Plant Pathology

Background:

• Pseudomonas syringae B728a produces the biosurfactant syringafactin.
• Syringafactin production is a surface contact-dependent trait.

Purpose of the Study:

• To investigate the molecular mechanisms underlying surface-dependent syringafactin production.
• To understand global gene expression changes in Pseudomonas syringae upon surface immobilization.

Main Methods:

• Utilized a gfp reporter gene fusion to measure syfA expression.
• Performed RNA sequencing to compare transcriptomes of planktonic and immobilized cells.
• Immobilized cells on various surfaces including glass, plastic, agar, and plant leaves.

Main Results:

• SyfA expression was significantly higher (over 4-fold) in immobilized cells compared to planktonic cells.
• SyfA induction occurred rapidly (within 2 hours) after surface contact.
• 3156 additional genes were differentially expressed, with distinct sets of genes repressed and induced in immobilized cells.

Conclusions:

• Surface contact rapidly and profoundly alters Pseudomonas syringae gene expression.
• These changes suggest anticipatory physiological responses to surface environments, potentially aiding biofilm formation and survival.
• The findings highlight the adaptability of P. syringae to different ecological niches, from aquatic habitats to plant surfaces.