Fluorescent pseudomonads secrete yellow-green siderophores named pyoverdines or pseudobactins. These comprise a dihydroxyquinoline derivative joined to a type-specific peptide and, usually, a carboxylic acid or amide. In Pseudomonas aeruginosa strain PAO1, six genes that encode proteins required for pyoverdine synthesis (pvd genes) have been identified previously. Expression of all of these gen...

Soil fumigation induces an ‘increased growth response’ (IGR) in crops of about 35%, even in soils with low pathogen and weed pressures (1). Populations of Pseudomonads and other bacteria increase in fumigated soils as soon as 2-wks after treatment (2). Some Pseudomonads can stimulate plant yields through the production of siderophores, growth promoting substances and by the suppression of soil-...