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Larvicidal activity of chimeric Bacillus thuringiensis protoxins
Author(s) -
Raymond K. C.,
John T. R.,
Bulla L. A.
Publication year - 1990
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1990.tb02046.x
Subject(s) - bacillus thuringiensis , biology , subspecies , amino acid , bioassay , toxin , bacillaceae , microbiology and biotechnology , biochemistry , bacteria , genetics , zoology , bacillus subtilis
Summary Bacillus thuringiensis subspecies kurstaki (Btk) and subspecies berliner (Btb) both produce lepidopteran‐specific larvicidal protoxins with different activities against the same insect species. Toxic activity resides in the amino‐terminal half of both protoxins, whereas the carboxy‐terminal half of the molecules is not required for toxicity. The protoxins are 90% homologous, with a major cluster of differences in the amino‐terminal half, and a 26 consecutive amino‐acid insertion within the carboxy‐terminal half of the Btk protoxin. Protoxin chimeras composed of the amino‐terminal half of one subspecies and the carboxy‐terminal half of the other were generated. Wild‐type and chimeric protoxins were compared in bioassays against tobacco horn worm larvae. The amino‐terminal half, the toxin itself, dictates specific larvicidal activity.