Bacteriophages Isolated in China for the Control of Pectobacterium carotovorum Causing Potato Soft Rot in Kenya
Soft rot is an economically significant disease in potato and one of the major threats to sustainable potato production. This study aimed at isolating lytic bacteriophages and evaluating methods for and the efficacy of applying phages to control potato soft rot caused by Pectobacterium carotovorum. Eleven bacteriophages isolated from soil and water samples collected in Wuhan, China, were used to infect P. carotovorum host strains isolated from potato tubers showing soft rot symptoms in Nakuru county, Kenya. The efficacy of the phages in controlling soft rot disease was evaluated by applying individual phage strains or a phage cocktail on potato slices and tubers at different time points before or after inoculation with a P. carotovorum strain. The phages could lyse 20 strains of P. carotovorum, but not Pseudomonas fluorescens control strains. Among the 11 phages, Pectobacterium phage Wc5r, interestingly showed cross-activity against Pectobacterium atrosepticum and two phage-resistant P. carotovorum strains. Potato slice assays showed that the phage concentration and timing of application are crucial factors for effective soft rot control. Phage cocktail applied at a concentration of 1 × 109 plaque-forming units per milliliter before or within an hour after bacterial inoculation on potato slices, resulted in ≥ 90% reduction of soft rot symptoms. This study provides a basis for the development and application of phages to reduce the impact of potato soft rot disease.
KeywordsPectobacterium carotovorum Potato soft rot Bacteriophages Phage resistance
We would like to thank Pei Zhang and An-Na Du from Core Facility and Technical Support, Wuhan Institute of Virology, for their assistance in providing TEM micrographs. This study was supported financially by the Sino-Africa Joint Research Centre (SAJC201605) and the Chinese Academy of Sciences (ZDRW-ZS-2016-4).
PM, FBM and HPW came up with the concept and designed the experiments. PM, JPY and ANM did the experiments. PM and JPY analysed the data. HPW, SK and FBM guided in developing the manuscript. All authors read and approved the final manuscript.
Compliance with Ethical Standards
Conflict of interest
All the authors declare that they have no conflict of interest.
Animal and Human Rights Statement
This article does not contain any studies with human or animal subjects performed by any of the Authors
- Chan BK, Abedon ST (2012) Phage therapy pharmacology: phage cocktails. Adv Appl Microbiol 78:1–23Google Scholar
- Darrasse A, Priou S, Kotoujansky A, Bertheau Y (1994) PCR and restriction fragment length polymorphism of a pel gene as a tool to identify Erwinia carotovora in relation to potato diseases. Appl Environ Microbiol 60:1437–1443Google Scholar
- Davidson RS (1948) Factors affecting the development of bacterial soft rot of potato tuber initials. Dissertation, University of MinnesotaGoogle Scholar
- De Boer S (2008) Managing soft rot and ring rot. In: Johnson DA (ed) Potato health management. APS Press, St Paul, pp 171–181Google Scholar
- FAO STAT (2013) Food and agriculture organization of the United Nations. Statistical databaseGoogle Scholar
- Hadas H, Einav M, Fishov, I, Zaritsky A (1997) Bacteriophage T4 development depends on the physiology of its host Escherichia coli. Microbiology 143:179–185Google Scholar
- Iriarte FB, Obradović A, Wernsing MH, Jackson LE, Balogh B, Hong JA, Vallad GE (2012) Soil-based systemic delivery and phyllosphere in vivo propagation of bacteriophages: two possible strategies for improving bacteriophage persistence for plant disease control. Bacteriophage 2(4):e23530CrossRefGoogle Scholar
- Rakhuba D, Kolomiets E, Dey ES, Novik G (2010) Bacteriophage receptors, mechanisms of phage adsorption and penetration into host cell. Pol J Microbiol 59:145–155Google Scholar