Підручник для студентів старших курсів

Glossary

Biological control – The use of living organisms to modify the agricultural ecosystem to control a crop disease or prevent the establishment of a pest. Rhizosphere – The root surface and that part of the soil directly influenced by the root system. Plant-growth-promoting rhizobacteria (PGPR) – Bacteria isolated from the rhizosphere, which have been shown to improve plant health or increase yield. They may exert their effects directly through the production of metabolites that can act as plant hormones and/or indirectly by the suppression of plant pathogens (biological control). Induced systemic acquired resistance – The ability of an agent, for example, a bacterium, chemical, virus, nematode, etc., to induce plant-defence mechanisms that lead to systemic resistance to a number of pathogens. Siderophore – Low-molecular-weight compound that is produced as a specific iron chelator by a microorganism.

Persistence may lead to improved competition and colonization of the producer strain on the plant surface, leading to niche-exclusion of the pathogen. The role of siderophores and other metabolite(s) in biocontrol may not be simply a direct antagonism of the pathogenic fungus, but may also involve more subtle ecological effects.

Alternative, more indirect, modes of action could involve stimulation of the plant’s own defence mechanisms by induced systemic acquired resistance or, possibly, by direct uptake and translocation of the metabolite within the plant.

D. N. Dowling and F. O’Gara are at the Department of
Microbiology, University College Cork, Ireland.

TIBTECH APRIL 1994 (VOL 12)

© 1994, Elsevier Science Ltd 0167 – 7799/94/S7.00
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