USE OF THE ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) AS A SEROLOGICAL SCREENING TEST IN STUDIES OF PEANUT RHIZOBIUM STRAINS

Abstract

ABSTRACT A double-antibody sandwich form of the enzyme-linked immunosorbent assay (ELISA) was used for serological identification of IS peanut Rhizobium strains both in cell suspension of pure culture and in single root nodules. This technique enabled specific detection of culture antigens in cell suspensions of 104-105 cells/ml. The serological ELISA specificity of strains tested generally follows that of the somatic agglutination. The use of the ELISA technique for counting peanut rhizobia in peat inoculants was evaluated. In dilutions of suspensions prepared from combined samples of Arachis hypogaea nodules positive ELISA values were obtained with 0.4 mg/ml fresh wt of nodule tissues. Even the smallest nodules, weighing only 2–8 mg, contained enough antigen for successful performance of the ELISA test. In mixed strain inoculation experiments using five peanut Rhizobium strains, the ELISA technique was employed to determine which strains were present in the nodules formed. An attempt was made to use ELI...