Transport of a biocontrol Pseudomonas fluorescens through 2.5-m deep outdoor lysimeters and survival in the effluent water

Details

Serval ID
serval:BIB_9803D21B2645
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Transport of a biocontrol Pseudomonas fluorescens through 2.5-m deep outdoor lysimeters and survival in the effluent water
Journal
Soil Biology and Biochemistry
Author(s)
Troxler J., Zala M., Natsch A., Nievergelt J., Keel C., Défago G.
ISSN
0038-0717
Publication state
Published
Issued date
1998
Volume
30
Number
5
Pages
621-631
Language
english
Abstract
Application of wild-type or genetically-modified bacteria to the soil environment entails the risk of dissemination of these organisms to the groundwater. To measure vertical transport of bacteria under natural climatic conditions, Pseudomonas fluorescens strain CHA0 was released together with bromide as a mobile tracer at the surface of large outdoor lysimeters. Two experiments, one starting in autumn 1993 and the other in spring 1994 were performed. Shortly after a heavy rainfall in late spring 1994, the released bacteria were detected for the first time in effluent water from the 2.5-m-deep lysimeters in both experiments, i.e. 210 d and 21 d, respectively, after inoculation. Only a 10−9 to 10−8 fraction of the inoculum was recovered as culturable cells in the effluent water, but a larger fraction of the CHA0 cells was in a non-culturable state as detected with immunofluorescence microscopy. As much as 50% of the mobile tracer percolated through the lysimeters, indicating that, compared with bromide, bacterial cells were retained in soil. In the second part of this study, persistence of CHA0 in groundwater microcosms consisting of lysimeter effluent water was studied for 380 d. Survival of the inoculant as culturable cells was better under anaerobic than under aerobic conditions. However, a large fraction of the cells became non-culturable in both cases. When the experiment was performed with filter-sterilized effluent water, the total count of introduced bacteria did not decline with time. In conclusion, the biocontrol strain was transported in low numbers to a potential groundwater level under natural climatic conditions, but could persist for an extended period in groundwater microcosms.
Web of science
Create date
17/02/2008 12:09
Last modification date
20/08/2019 14:59
Usage data