Soil-borne Verticillium wilt update July 2015
Bacterial strains of the bacteria genus Serratia and Paenibacillus have shown a strong potential as biocontrol agents (BCAs) for treatment of Verticillium wilt. The analysis of the genomes of the selected Serratia and Paenibacillus strains significantly contributed to understanding mode of action of these potential BCAs: it was shown that they contain several genes putatively involved in biocontrol and plant growth promotion.
In the last months, the sequence of the selected Paenibacillus strain was used to develop a strain-specific marker that will facilitate identification of the applied strain in the soil samples. The interactions between the biological control agent (BCA) and the pathogen was studied. Both BCAs showed strong ability to inhibit growth of Verticillium on the plate.
Defining the crop and cultivar-specific minimum effective dose
In order to develop a novel method for seed treatment against Verticillium wilt in oilseed rape and Brassica vegetables we first have evaluated the plant growth promotion potential of ten endophytic Serratia and Paenibacillus strains that were in vitro shown to be Verticillium antagonists. We found that plant growth promotion depended on the plants’ growth conditions and were able to select one strain of each genus for further studies.
In order to test the biocontrol activity of the BCAs and estimate the minimal effective dose ad planta, the bioassay has been optimized. PCR primers developed for Paenibacillus polymyxa and Serratia spp. were used for identification of the BCAs in the plants rhizosphere enabling estimation of the root colonization capacity of the BCAs.
Read more about our research in the following scientific publications
Rybakova D, Wetzlinger U, Müller H, Berg G (2015) Complete genome sequence of Paenibacillus polymyxa strain SB3-1, a soilborne bacterium with antagonistic activity toward plant pathogens. Genome announcements, 3(2), e00052-15.
Rybakova D, Schmuck M, Wetzlinger U, Varo Suarez A, Murgu O, Müller H, Berg G (2015) Kill or cure? The interaction between endophytic Paenibacillus and Serratia strains and the host plant is shaped by plant growth conditions. Plant and soil.
Rybakova D, Cernava T, Köberl M, Liebminger S, Etemadi M, Berg G (2015) Endophytes-assisted biocontrol: novel insights in ecology and the mode of action of Paenibacillus. Plant and soil.