A genetically engineered mosquitocidal cyanobacterium

Larvae of the mosquito Aedes aegypti ingested, and developed into adults, on a diet of 1O of 14 different species of cyanobacteria including Agmenellum quadruplicatum PR-6 (=Synechococcus PCC7002). Mosquito larvae ingested and grew on cells of PR-6 adapted to growth in the absence of NaCl. The cryIVD gene of Bacillus thuringiensis var. israelensis was cloned into a PR-6 expression vector to form pAQRM56, which was transformed into PR-6. Expression of the CryIVD protein in PR-6 was demonstrated by immunocytochemistry and larvicidal activity. Immunogold labelling indicated production of an electron-dense material among the thylakoid membranes of PR-6. Cells of PR-6 carrying pAQRM56 were toxic to the larvae of A. aegypti whereas control cells were not. Growth of PR-6 cells carrying pAQRM56 was slower than the growth of control cells and these cells were also larger.