VIEW ARTICLE

Techniques

Species-Specific and Cross-Reactive Monoclonal Antibodies to the Plant-Pathogenic Spiroplasmas Spiroplasma citri and S. kunkelii. Ramon L. Jordan, Research plant pathologist, Florist and Nursery Crops Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD 20705; Meghnad Konai(2), Ing-Ming Lee(3), and Robert E. Davis(4). (2)Postdoctoral research associate, U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD 20705; (3)(4)Research plant pathologists, Microbiology and Plant Pathology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD 20705. Phytopathology 79:880-887. Accepted for publication 27 March 1989. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1989. DOI: 10.1094/Phyto-79-880.

A panel of 46 murine monoclonal antibody-secreting hybridomas was developed from mice immunized with a mixture of strains of Spiroplasma citri (M24OH) and S. kunkelii (I-747, F32, and PU8-17). Monoclonal antibodies with a range of specificities were selected in enzyme-linked immunosorbent assay (ELISA) tests by using intact and disrupted spiroplasma cells and purified spiroplasma cell membrane preparations. Forty of the monoclonal antibodies recognized antigenic sites found on Ig-trapped intact spiroplasmas and spiroplasma membrane preparations, whereas the remaining six monoclonal antibodies reacted only with disrupted spiroplasma cells in indirect ELISA. When used with 36 strains of spiroplasmas representing group I and groups III–XI spiroplasmas, 17 monoclonal antibodies reacted specifically with strains of S. citri (subgroup I-1), and an additional 17 monoclonal antibodies reacted only with S. kunkelii (subgroup I-3) strains. The remaining 12 monoclonal antibodies reacted with antigenic sites common in three to eight of the eight group I subgroups, including honeybee spiroplasmas, S. melliferum (I-2), 277F spiroplasma (I-4), green leaf bug spiroplasmas (I-5), Maryland flower spiroplasma (I-6), Cocos spiroplasmas (I-7), and the periwinkle spiroplasma, S. phoeniceum (I-8). None of the monoclonal antibodies reacted with any non-group I spiroplasmas tested. At least 17 different antigenic sites were defined by the 46 monoclonal antibodies. These discriminatory serological reagents will be useful for the detection and identification of spiroplasmas in plants and insects and for providing information on the antigenic relationships among other spiroplasma strains and newly recognized spiroplasmas.