Production and characteristics of antisera to Spiroplasma citri and clover phyllody-associated antigens derived from plants

Antisera were produced to clover phyllody- and Spiroplasma citri-associated antigens partially purified from infected Vinca rosea plants. Separate antisera were made to ‘membrane fraction’ (MF) preparations comprising the resuspended pellet obtained by high speed centrifugation, and to ‘soluble fraction’ (SA) preparations, comprising the supernatant from high speed centrifugation concentrated by freeze-drying. All antisera showed considerable activity against normal plant antigens but after cross-absorption with extracts of healthy plants the MF antisera were used in F(ab')₂based ELISA tests to detect S. citri- or clover phyllody-associated antigens in infected plants. The ‘clover phyllody’ antiserum also reacted specifically with extracts of clover plants with phyllody, and with naturally-infected strawberry plants showing symptoms of green petal disease. Both the ‘clover phyllody’ and S. citri antisera were specific for their respective homologous antigens. No cross-reactions were observed in heterologous tests or between either antiserum and extracts of V. rosea infected with various MLOs obtained from different host plants.