Open AccessDifferential Ability of Genotypes of 2,4-Diacetylphloroglucinol-Producing Pseudomonas fluorescens Strains To Colonize the Roots of Pea Plants
Author(s) -
Blanca B. Landa,
Olga V. Mavrodi,
Jos M. Raaijmakers,
Brian B. McSpadden Gardener,
Linda S. Thomashow,
David M. Weller
Publication year - 2002
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.68.7.3226-3237.2002
Subject(s) - biology , rhizosphere , pseudomonas fluorescens , pseudomonas , genotype , population , fusarium oxysporum , fusarium , botany , microbiology and biotechnology , multilocus sequence typing , bacteria , gene , genetics , demography , sociology
Indigenous populations of 2,4-diacetylphloroglucinol (2,4-DAPG)-producing fluorescent Pseudomonas spp. that occur naturally in suppressive soils are an enormous resource for improving biological control of plant diseases. Over 300 isolates of 2,4-DAPG-producing fluorescent Pseudomonas spp. were isolated from the rhizosphere of pea plants grown in soils that had undergone pea or wheat monoculture and were suppressive to Fusarium wilt or take-all, respectively. Representatives of seven genotypes, A, D, E, L, O, P, and Q, were isolated from both soils and identified by whole-cell repetitive sequence-based PCR (rep-PCR) with the BOXA1R primer, increasing by three (O, P, and Q) the number of genotypes identified previously among a worldwide collection of 2,4-DAPG producers. Fourteen isolates representing eight different genotypes were tested for their ability to colonize the rhizosphere of pea plants. Population densities of strains belonging to genotypes D and P were significantly greater than the densities of other genotypes and remained above log 6.0 CFU (g of root)(-1) over the entire 15-week experiment. Genetic profiles generated by rep-PCR or restriction fragment length polymorphism analysis of the 2,4-DAPG biosynthetic gene phlD were predictive of the rhizosphere competence of the introduced 2,4-DAPG-producing strains.