RESUMO
One of the most economically important bacterial pathogens of plants and plant products is Dickeya dadantii. This bacterium causes soft rot disease in tubers and other parts of the potato and other plants of the Solanaceae family. The application of restricted host range bacteriophages as biocontrol agents has recently gained widespread interest. This study purposed to isolate the infectious agent of the potato and evaluate its biocontrol by bacteriophages. Two phytopathogenic strains were isolated from infected potatoes, identified based on biochemical and 16S rRNA gene sequencing, and submitted to GenBank as D. dadantii strain pis3 (accession no. HQ423668) and D. dadantii strain sip4 (accession no. HQ423669). Their bacteriophages were isolated from Caspian Sea water by enriching the water filtrate with D. dadantii strains as hosts using spot or overlay methods. On the basis of morphotypes, the isolated bacteriophages were identified as members of the Myoviridae and Siphoviridae families and could inhibit the growth of antibiotic resistant D. dadantii strains in culture medium. Moreover, in Dickeya infected plants treated with bacteriophage, no disease progression was detected. No significant difference was seen between phage-treated and control plants. Thus, isolated bacteriophages can be suggested for the biocontrol of plant disease caused by Dickeya strains.
Assuntos
Bacteriófagos/isolamento & purificação , Agentes de Controle Biológico/isolamento & purificação , Dickeya chrysanthemi/crescimento & desenvolvimento , Dickeya chrysanthemi/virologia , Doenças das Plantas/microbiologia , Solanum tuberosum/microbiologia , Bacteriófagos/classificação , Sequência de Bases , Agentes de Controle Biológico/classificação , DNA Bacteriano/genética , Dickeya chrysanthemi/efeitos dos fármacos , Dickeya chrysanthemi/isolamento & purificação , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Myoviridae/classificação , Myoviridae/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Siphoviridae/classificação , Siphoviridae/isolamento & purificaçãoRESUMO
One of the most economically important bacterial pathogens of plants and plant products is
Assuntos
Bacteriófagos/isolamento & purificação , Agentes de Controle Biológico/isolamento & purificação , Dickeya chrysanthemi/crescimento & desenvolvimento , Dickeya chrysanthemi/virologia , Doenças das Plantas/microbiologia , Solanum tuberosum/microbiologia , Sequência de Bases , Bacteriófagos/classificação , Agentes de Controle Biológico/classificação , DNA Bacteriano/genética , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Myoviridae/classificação , Myoviridae/isolamento & purificação , Dickeya chrysanthemi/efeitos dos fármacos , Dickeya chrysanthemi/isolamento & purificação , /genética , Análise de Sequência de DNA , Siphoviridae/classificação , Siphoviridae/isolamento & purificaçãoRESUMO
Isolation of antigens on immunomagnetic beads and subsequent analysis with SDS-PAGE and Western blotting (immunomagnetic isolation-Western blotting (IMI-WB)) was used to verify positive ELISA results for Erwinia chrysanthemi and Erw. carotovora subsp. atroseptica in potato peel extracts. Direct analysis of highly contaminated extracts by Western blotting without previous immuno-isolation resulted in background reactions, whereas immunomagnetic isolation resulted in distinct bands of specific antigens. Target cells as well as antigenic cell products were captured in IMI-WB. Band patterns on IMI-WB of cell-free culture filtrates and cell suspensions were highly similar, but the removal of cells lowered the detection level by 10- to 100-fold. Threshold levels of IMI-WB were generally comparable with those of ELISA. No differences in threshold levels and band patterns were found between a direct format and an indirect format of immuno-isolation. In IMI-WB, blotting patterns differed between Erw. chrysanthemi and Erw. carotovora subsp. atroseptica. The patterns were identical for 15 Erw. chrysanthemi strains, isolated from potato peel extracts in The Netherlands. However, one of 15 strains of Erw, carotovora subsp. atroseptica from potato peel extracts in The Netherlands gave an aberrant pattern. Target bacteria could be easily distinguished from those of cross-reacting strains on the basis of band patterns. Potato peel extracts naturally contaminated with Erw. chrysanthemi gave IMI-WB patterns that were similar to pure cultures of the homologous strains.