Pseudomonas fluorescens PSB

Pseudomonas fluorescens PSB is a dual-action phosphorus-solubilizing and plant growth-promoting rhizobacterium (PGPR) that combines phosphate mobilization with powerful biocontrol properties. This versatile bacterium produces siderophores (iron-chelating compounds) that outcompete pathogens for iron, hydrogen cyanide (HCN) that suppresses soil-borne diseases, and phosphatase enzymes that mineralize organic phosphorus. Particularly valuable in alkaline and calcareous soils where phosphorus fixation is severe and chemical fungicides may be restricted.

P. fluorescens colonizes root surfaces rapidly, establishing a protective biofilm. Phosphorus solubilization occurs via gluconic acid secretion and phosphatase enzyme production. Biocontrol operates through: (1) siderophore production — fluorescent pyoverdines sequester iron, starving pathogens; (2) HCN production — volatile cyanide inhibits pathogen respiration; (3) induced systemic resistance (ISR) — triggers plant defense pathways. The fluorescent pigment (pyoverdine) that gives the species its name is visible under UV light and serves as a quality indicator.

Ideal For

Store refrigerated (4-10°C) for maximum viability. Acceptable at ambient (<25°C) for up to 3 months. Shake well before use. Shelf life: 12 months refrigerated. Protect from direct sunlight and temperatures above 30°C.