Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 15, 2006
Publication Date: August 1, 2006
Citation: Sudarshana, P., Mcclean, A.E., Kluepfel, D.A. 2006. Effect of temperature and detergents on agrobacterium tumefaciens, the causal pathogen of crown gall disease of walnut. American Phytopathological Society Abstracts. Technical Abstract: Crown gall disease caused by the bacterium Agrobacterium tumefaciens causes significant economic losses in commercial walnut orchards and nursery operations in California. In an effort to develop integrated control strategies to ensure pathogen and disease free plant material at nurseries, the effects of detergents and temperature on growth and survival of Agrobacterium tumefaciens were investigated. At temperatures above 37 degrees C and below 15 degrees C in-vitro bacterial multiplication rates were significantly repressed. A. tumefaciens did not survive above 45 degrees C. Exposure to a range of concentrations of cationic and non-ionic detergents significantly reduced bacterial survival. Exposure to the anionic detergent SDS, at 0.1% and 1% concentrations, showed limited effect on bacterial viability. Among the detergents tested, cetyltrimethylammonium bromide (CTAB) was the most effective reducing bacterial populations below detection limits at concentrations above 0.01% (V/V). Data on the synergistic effect of combining detergent exposure with 1 to 3 freeze-thaw cycles also will be presented. The use of detergent washes combined with manipulation of pre-plant seedling storage temperatures may reduce the incidence of crown gall on walnut under orchard conditions.