Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: February 1, 2004
Publication Date: July 5, 2004
Citation: Mazzola, M., Funnell, D., Raaijmakers, J. 2004. Plant genotype specific selection of rhizosphere-inhabiting 2,4-dapg-producing fluorescent pseudomonas spp. from resident soil populations. Proceedings, Rhizosphere 2004: Perspectives and Challenges. p. 180. Interpretive Summary: Abstract only.
Technical Abstract: Emerging evidence indicates a role for plant genotype as a determinant of species and genetic composition of saprophytic soil microbial communities. Studies were conducted to determine the impact of wheat or apple genotpe on genetic composition of the fluorescent pseudomonad populations recovered from the rhizosphere and capacity to enhance resident populations of 2,4-DAPG-producing strains, a group of bacteria known to provide biological disease control. DAPG-producing strains were recovered from the rhizosphere of wheat cultivar Lewjain at populations higher than those recovered from other wheat cultivars. Based on genetic analyses two previously undefined ph1D+ gentoypes (PfZ and PfY) were identified. Lewjain and Penwawa were the primary source of genotype PfY and PfZ isolates, respectively. Fluorescent pseudomonad populations from seedling and G16 apple rootstocks were dominated by genotype 13 while genotype 1 dominated populations from Bud9, M7, M26 and MM106. Genotype 9 (=2,4-DAPG-producing) was present in the population from G16 irrespective of the soil system. These results add further to evidence indicating specificity in interactions between plants and saprophytic solid microbes. As 2,4-DAPG-producing Pseudomonas spp. have a central role in take-all decline, we postulate that the use of cultivars possessing a superior capacity to enhance resident populations of these bacteria may reduce length of the monoculture period required to induce natural supressiveness of soils toward this disease.