Persistence of a biocontrol Pseudomonas inoculant as high populations of culturable and non-culturable cells in 200-cm-deep soil profiles

Détails

ID Serval
serval:BIB_9B2C4D53447C
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Persistence of a biocontrol Pseudomonas inoculant as high populations of culturable and non-culturable cells in 200-cm-deep soil profiles
Périodique
Soil Biology and Biochemistry
Auteur⸱e⸱s
Troxler J., Svercel M., Natsch A., Zala M., Keel C., Moënne-Loccoz Y., Défago G.
ISSN
0038-0717 (Print)
Statut éditorial
Publié
Date de publication
2012
Volume
44
Numéro
1
Pages
122-129
Langue
anglais
Résumé
Little is known about the ecology of soil inoculants used for pathogen biocontrol, biofertilization and bioremediation under field conditions. We investigated the persistence and the physiological states of soil-inoculated Pseudomonas protegens (previously Pseudomonas fluorescens) CHA0 (108 CFU g−1 surface soil) in different soil microbial habitats in a planted ley (Medicago sativa L.) and an uncovered field plot. At 72 days, colony counts of the inoculant were low in surface soil (uncovered plot) and earthworm guts (ley plot), whereas soil above the plow pan (uncovered plot), and the rhizosphere and worm burrows present until 1.2 m depth (ley plot) were survival hot spots (105-106 CFU g−1 soil). Interestingly, strain CHA0 was also detected in the subsoil of both plots, at 102-105 CFU g−1 soil between 1.8 and 2 m depth. However, non-cultured CHA0 cells were also evidenced based on immunofluorescence microscopy. Kogure's direct viable counts of nutrient-responsive cells showed that many more CHA0 cells were in a viable but non-culturable (VBNC) or a non-responsive (dormant) state than in a culturable state, and the proportion of cells in those non-cultured states depended on soil microbial habitat. At the most, cells in a VBNC state amounted to 34% (above the plow pan) and those in a dormant state to 89% (in bulk soil between 0.6 and 2 m) of all CHA0 cells. The results indicate that field-released Pseudomonas inoculants may persist at high cell numbers, even in deeper soil layers, and display a combination of different physiological states whose prevalence fluctuates according to soil microbial habitats.
Mots-clé
VBNC bacteria, Immunofluorescence, Earthworms, Pseudomonas, Soil inoculant, Soil profiles, Survival
Web of science
Création de la notice
23/06/2011 13:42
Dernière modification de la notice
20/08/2019 15:02
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