USE OF POLYCLONAL ANTIBODIES TO IDENTIFY MYCOPLASMA-LIKE ORGANISMS (MLOS) FROM THE SUDAN AND FROM THAILAND

Rabbit polyclonal antibodies prepared against faba bean phyllody MLO f rom the Sudan reacted with its homologous antigen and with extracts of Catharanthus roseus experimentally infected with the same or a relate d MLO from Crotalaria saltiana showing symptoms of phyllody disease, a s well as with extracts of naturally MLO-infected C. saltiana growing in the field in the Sudan. The antibodies also reacted positively with extracts of C. roseus experimentally infected with Crotalaria juncea phyllody MLO and soybean phyllody MLO from Thailand. Polyclonal antibo dies prepared against an MLO associated with witches' broom disease in C. juncea reacted positively in ELISA tests with homologous antigen e xtracts from naturally infected C. juncea as well as with extracts fro m experimentally infected C. roseus and with extracts prepared from Se samum indicum plants with phyllody symptoms growing in Thailand. There was no reaction between these antibodies and extracts from C. roseus plants infected with the MLOs associated with C. juncea phyllody or wi th soybean phyllody. No cross reactions were observed among the antige ns and antibodies of the two MLO groups by immunoflorescence, ELISA or western blotting. However, the molecular weight of the principal prot ein antigen, determined by SDS-polyacrylamide gel electrophoresis (SDS -PAGE) and western blotting was the same for both types of MLO. Serolo gically-similar MLOs thus occur in the Sudan and in Thailand, where th ey are associated with phyllody symptoms in C. saltiana and faba bean and with C. juncea and soybean, respectively. A second, serologically distinct MLO group was also found infecting C. juncea and S. indicum i n Thailand but MLOs from this group have not yet been identified in cr ops from the Sudan.