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Selection of bacteria able to control Fusarium oxysporum f. sp. radicis‐lycopersici in stonewool substrate
Author(s) -
Validov S.,
Kamilova F.,
Qi S.,
Stephan D.,
Wang J.J.,
Makarova N.,
Lugtenberg B.
Publication year - 2007
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/j.1365-2672.2006.03083.x
Subject(s) - bacteria , biology , fusarium oxysporum , microbiology and biotechnology , fusarium oxysporum f.sp. lycopersici , selection (genetic algorithm) , biological pest control , botany , artificial intelligence , fusarium wilt , computer science , genetics
Aims: Tomato foot and root rot (TFRR), caused by Fusarium oxysporum f. sp. radicis ‐ lycopersici ( Forl ), is an economically important disease of tomato. The aim of this study was to develop an efficient protocol for the isolation of bacteria, which controls TFRR based on selection of enhanced competitive root‐colonizing bacteria from total rhizosphere soil samples. Methods and Results: A total of 216 potentially enhanced bacterial strains were isolated from 17 rhizosphere soil samples after applying a procedure to enrich for enhanced root tip colonizers. Amplified ribosomal DNA restriction analysis, in combination with determination of phenotypic traits, was introduced to evaluate the presence of siblings. One hundred sixteen strains were discarded as siblings. Thirty‐eight strains were discarded as potential pathogens based on the sequence of their 16S rDNA. Of the remaining strains, 24 performed equally well or better than the good root colonizer Pseudomonas fluorescens WCS365 in a competitive tomato root tip colonization assay. Finally, these enhanced colonizers were tested for their ability to control TFRR in stonewool, which resulted in seven new biocontrol strains. Conclusions: The new biocontrol strains, six Gram‐negative and one Gram‐positive bacteria, were identified as three Pseudomonas putida strains and one strain each of Delftia tsuruhatensis , Pseudomonas chlororaphis , Pseudomonas rhodesiae and Paenibacillus amylolyticus . Significance and Impact of the Study: We describe a fast method for the isolation of bacteria able to suppress TFRR in stonewool, an industrial plant growth substrate. The procedure minimizes the laborious screens that are a common feature in the isolation of biocontrol strains.