Plant growth-promoting rhizobacteria PGPR

The ISR response is triggered by infection of plant roots by specific strains of plant growth-promoting rhizobacteria (PGPRs) and is mediated sequentially by jasmonic acid and ethylene within the plant, but does not result in the accumulation of SA or PRPs [53]. In addition, the ISR response is limited by the ability of the PGPRs to induce ISR in specific plant species and genotypes [54, 55]. Antipathogenic compounds produced by ISR have yet to be identified. The induction of SAR appears to inhibit ISR response. 

Phytohormones and phytotoxins are two major classes of compounds produced and secreted by microorganisms that act on plants. These will be discussed in another chapter (4.10). Recendy, production of 2,3-butanediol (186) and acetoin (187) by two strains of plant growth-promoting rhizobacteria (PGPR) was reported. These compounds promote growth of A. thaliana and trigger induced systemic resistance (ISR) in the plant.108 109... 

Jetiyanon, K., Tuzun, S., Kloepper J. Lignification, peroxidase and superoxide dismutases as early plant defence reactions associated with PGPR-mediated induced systemic resistance. In, Plant growth-promoting rhizobacteria present status and future prospects. Kobayashi, K., Homma, Y., Kodama, F., KondoN., Akino, S. eds. OECD Paris, France, 1997 pp. 265-268. 

Tuzun S., Kloepper J.W. Induced systemic resistance by plant growth promoting rhizobacteria. In Improving Plant Productivity with Rhizosphere Bacteria. Ryder, M.H., Stephens, P.M., Bowen, GD. eds. Proceedings of 3rd International Workshop on PGPR. CSIRO, Division of Soils Adelaide. 1994 pp. 104-109. 

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