INSECTICIDAL PHIZOBIACEAE CELLS

摘要

Complete and partial Bacillus thuringiensis var. kurstaki HD-73 crystal protein protoxin genes were cloned into pRK290. E. coli cells harboring these recombinant plasmids produced protein that was toxic to Manduca sexta (tobacco hornworm) larvae. These plasmids were unstable in and inhibitory of the growth of Agrobacterium and Rhizobium cells; the presence of a complete protoxin gene being far more destabilizing and inhibitory than the presence of a partial protoxin gene. Rhizobium cells containing a partial protoxin gene formed root nodules in legume roots which were toxic to M. sexta larvae. Plasmids carrying complete protoxin genes were totally incompatable with root nodule formation; bacteroids in nodules formed by inoculation with stains containing the complete gene did not contain the gene-carrying plasmid and nodules were not toxic to insect larvae. The invention provides methods to produce insecticidal protein by constructing partial protoxin genes followed by expression of the genes in bacteroids and Rhizobiaceae cells. Useful plasmids and cells are also provided.