Submitted to: Journal of Sugar Beet Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2007
Publication Date: 1/1/2007
Citation: Caesar, T., Lartey, R.T., Shelver, W.L. 2007. Enzyme-linked immunosorbent assay for Cercospora beticola in soil. Journal of Sugar Beet Research. 44(1-2): 51-70. Interpretive Summary: Cercospora beticola Sacc. causes leaf spot in sugar beet and lesions in safflower. Severe disease pressure results in significant loss of root yield and reduction of recoverable sugar. Even though C. beticola survives in the soil for years, it is considered a foliar pathogen. Cercospora leaf spot is mainly controlled with foliar applied chemicals, but recently, attempts to control the pathogen have been made through foliar application with biological agents. There is need to evaluate the inoculum of C. beticola in soil after application of control agents. To our knowledge, there is no report on the detection and quantification of C. beticola in soil. We developed an immunological technique that could be used to follow the survival and longevity of the fungal pathogen in soil. Knowledge of the inoculum in soil will allow farmers to better monitor chemical application or application of biocontrol agents to control the disease incidence.
Technical Abstract: An enzyme-linked immunosorbent assay (ELISA) was developed to detect antigens from Cercospora beticola in soil. Amounts as small as 1.5 µg of freeze-dried C. beticola mycelia dispersed in carbonate buffer were detected. Fungi from different genera (Ascomycetes, Basidiomycetes, and Hyphomycetes) showed negligible cross reactivity with the polyclonal antibodies, except for Fusarium and Trichoderma species. To reduce cross reactivity of the antibodies to these fungal species, a technique based on pre-adsorption of the antibodies is described. Evaluation of field soil naturally infested with C. beticola testing showed that the assay using pre-adsorbed serum is a reliable diagnostic tool to replace or augment current isolation and detection methods. The assay should find broad use for the detection and quantification of Cercospora beticola mycelia in soil samples.