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Abstract
Induction of the expression of the delta-endotoxin gene from Bacillus thuringiensis var.
tenebrionis in the recombinant strain Pseudomonas putida IPM-36 negatively affected the viability
and the growth rate of the culture. In order to optimize the insecticide production by the recombinant
strain, mutant clones exhibiting anticipating growth on an inducer-containing medium were selected
and studied. These clones differed in such aspects as the localization of mutations (either in
plasmid pBTN11, carrying the cry3A gene, or in the chromosome), growth rate, or the level of
delta-endotoxin synthesis after induction. Several mutants obtained proved much superior to
P. putida IPM-36 in their structural and segregation stability, although they were as efficient
as the original strain with respect to the production of the insecticide (protei Cry3A). |
