Editor: Christoph Tebbe
Effect of bacterial antagonists on lettuce: active biocontrol of Rhizoctonia solani and negligible, short-term effects on nontarget microorganisms
Article first published online: 30 JAN 2008
© 2008 Federation of European Microbiological Societies Published by Blackwell Publishing Ltd
FEMS Microbiology Ecology
Volume 64, Issue 1, pages 106–116, April 2008
How to Cite
Scherwinski, K., Grosch, R. and Berg, G. (2008), Effect of bacterial antagonists on lettuce: active biocontrol of Rhizoctonia solani and negligible, short-term effects on nontarget microorganisms. FEMS Microbiology Ecology, 64: 106–116. doi: 10.1111/j.1574-6941.2007.00421.x
- Issue published online: 30 JAN 2008
- Article first published online: 30 JAN 2008
- Received 6 April 2007; revised 13 September 2007; accepted 15 September 2007.First published online 30 January 2008.
- Rhizoctonia solani;
The aim of this study was to assess the biocontrol efficacy against Rhizoctonia solani of three bacterial antagonists introduced into naturally Rhizoctonia-infested lettuce fields and to analyse their impact on the indigenous plant-associated bacteria and fungi. Lettuce seedlings were inoculated with bacterial suspensions of two endophytic strains, Serratia plymuthica 3Re4-18 and Pseudomonas trivialis 3Re2-7, and with the rhizobacterium Pseudomonas fluorescens L13-6-12 7 days before and 5 days after planting in the field. Similar statistically significant biocontrol effects were observed for all applied bacterial antagonists compared with the uninoculated control. Single-strand conformation polymorphism analysis of 16S rRNA gene or ITS1 fragments revealed a highly diverse rhizosphere and a less diverse endophytic microbial community for lettuce. Representatives of several bacterial (Alpha-, Beta- and Gammaproteobacteria, Firmicutes, Bacteriodetes), fungal (Ascomycetes, Basidiomycetes) and protist (Oomycetes) groups were present inside or on lettuce plants. Surprisingly, given that lettuce is a vegetable that is eaten raw, species of genera such as Flavobacterium, Burkholderia, Staphylococcus, Cladosporium and Aspergillus, which contain potentially human pathogenic strains, were identified. Analysis of the indigenous bacterial and endophytic fungal populations revealed only negligible, short-term effects resulting from the bacterial treatments, and that they were more influenced by field site, plant growth stage and microenvironment.