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Efficacy of hydrogen peroxide treatment for control of hairy root disease caused by rhizogenic agrobacteria
Author(s) -
Bosmans L.,
Van Calenberge B.,
Paeleman A.,
Moerkens R.,
Wittemans L.,
Van Kerckhove S.,
De Mot R.,
Lievens B.,
Rediers H.
Publication year - 2016
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.13187
Subject(s) - agrobacterium , catalase , hydrogen peroxide , population , agrobacterium tumefaciens , horticulture , microbiology and biotechnology , biology , biofilm , bacteria , strain (injury) , chemistry , transformation (genetics) , biochemistry , enzyme , medicine , genetics , environmental health , gene , anatomy
Aims Rhizogenic Agrobacterium strains are the causative agent of hairy root disease (HRD), an increasing problem in the hydroponic cultivation of tomato and cucumber in Europe. A previous study has demonstrated that different lineages of rhizogenic agrobacteria are able to form biofilms. Although hydrogen peroxide (H 2 O 2 ) is a frequently used biocide in hydroponic systems, until now its effectiveness to remove rhizogenic agrobacteria has not been unequivocally demonstrated. Therefore, the main objective of this study was to assess the efficacy of H 2 O 2 in controlling Agrobacterium ‐containing biofilms. Methods and Results Using lab‐scale experiments, we found a huge variation between different rhizogenic Agrobacterium strains in EC 50 values, ranging from 18·8 to 600 ppm H 2 O 2 , representing the lowest and highest concentration tested respectively. Using pilot‐scale experiments in which different H 2 O 2 concentrations were tested, treatment with 25 ppm H 2 O 2 was found to be ineffective. In contrast, treatment with 50 ppm significantly affected a catalase‐negative Agrobacterium population, while a catalase‐positive population was only marginally affected. For the catalase‐positive Agrobacterium population, a treatment of 100 ppm H 2 O 2 was required to be effective. Finally, H 2 O 2 treatment of HRD in two commercial greenhouses was monitored, and showed that the H 2 O 2 concentration decreased considerably towards the end of the irrigation circuits. Further, a clear correlation was found between the actual concentration of H 2 O 2 and the incidence of HRD. Conclusion We showed that H 2 O 2 may be effective to reduce biofilm formation by rhizogenic bacteria. Nevertheless, it was clear from our results that the required H 2 O 2 concentration depends on the particular Agrobacterium strain(s) present in the greenhouse. Significance and Impact of the Study This is the first study that examined the effectiveness of H 2 O 2 to control HRD in hydroponic systems, and the effect of catalase activity on H 2 O 2 effectiveness. Our study has direct relevance for the highly intensive horticultural sector.