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United States Department of Agriculture

Agricultural Research Service

Research Project: Alternatives to methyl bromide soil fumigation for vegetable and floriculture production

Location: Subtropical Plant Pathology Research

Title: An Observation of Bacterial Population Changes in Fields Treated with Anaerobic Soil Disinfestation

Authors
item Hong, Jason
item Martian, Kendall -
item Burelle, Nancy
item Butler, David -
item Rosskopf, Erin

Submitted to: American Phytopathology Society
Publication Type: Abstract Only
Publication Acceptance Date: March 22, 2013
Publication Date: N/A

Interpretive Summary: Anaerobic soil disinfestation (ASD) is an effective control measure for soilborne plant pathogens and nematodes. However, the mechanism by which soil disinfestation is achieved is poorly understood. In this study soil samples were taken before, during and after ASD treatment Using molecular biology techniques it was established that Bacillus or Paenibacillus species populations change as a result of the application of ASD. Many species in the genera are used as biological control agents for plant pathogens. These genera may play a role in the effects seen when using ASD.

Technical Abstract: Anaerobic soil disinfestation (ASD) has proven to be effective for pathogen and nematode control as an alternative to fumigation. It has been hypothesized that various bacterial populations could play key roles in the disinfestation process through the production of secondary metabolites. In this study, ASD was applied to two fields in southern Florida. Soil samples were taken 2-3 days prior to and during application of the treatment. DNA was extracted from the samples. Using universal bacterial primers, V2 and V3, with Length Heterogeneity pcr (LH-PCR) and next generation sequencing, various bacterial populations were identified. One population of interest, of amplicon size 445 (+/-3bp), was rarely detected in the pretreatment samples, and when it was detected made up less than 20% of the total population. Samples taken 48 hrs post ASD application, showed that this population increased to make up 24-78% of the total detected bacterial population. The 445 amplicon was found in all the treated soil samples throughout the study. The population increase of this amplicon correlated with a decrease in soil pH. Changes in the 445 amplicon population and soil pH in the untreated control were not significant. Using cloning and next generation sequencing techniques and BLASTn these amplicons were identified as Bacillus and Paenibacillus species.

Last Modified: 4/16/2014
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