GENOTYPE CHARACTERIZATION OF THE BACTERIUM EXPRESSING THE MALE-KILLING TRAIT IN THE LADYBIRD BEETLE ADALIA-BIPUNCTATA WITH SPECIFIC RICKETTSIAL MOLECULAR TOOLS

The male-killing ladybird beetle (LB) bacterium (AB bacterium) was ana lyzed with specific rickettsial molecular biology tools in the LB Adal ia bipunctata strains. Eight phenotype;positive LB strains shoeing mor tality of male embryos were amplified with rickettsial genus-specific primers from the gene for citrate synthase (CS) and the gene for a 17- kDa protein and spotted fever group-specific primers from the gene for the 120-kDa outer membrane protein (ompB), The specificity of amplifi cation was confirmed by Southern hybridization and the absence of the above-listed gene products in three phenotype negative LB strains, Res triction polymorphism patterns of three examined amplicons from the CS gene, 17-kDa-protein gene, and ompB gene were identical among the eig ht phenotype-positive LB strains and were unique among all known ricke ttsiae of the spotted fever and typhus groups, Amplified fragments of the CS genes of the AB bacterium, Rickettsia prowazekii Breinl, Ricket tsia typhi Wilmington, Rickettsia canada 2678, and Rickettsia conorii 7 (Malish) were sequenced. The greatest differences among the above-li sted rickettsial and AB bacterium CS gene sequences were between bp 10 78 and 1110. Numerical analysis based on CS gene fragment sequences sh ows the close relationships of the AB bacterium to the genus Rickettsi a. Expanding of knowledge about rickettsial arthropod vectors and part icipation df rickettsiae in the cytoplasmic maternal inheritance of ar thropods is discussed.