Resistance to commercial Bti toxin mixture and
to separate Bti toxins
After 18 generations of selection, the LiTOX strain exhibited a
small but significant increase in resistance to commercial Bti toxin
mixture (Table 1) with an RR50 of twofold. This resistance level was
significantly lower than the resistance level measured for toxic leaf
litter. The LiTOX strain was significantly resistant to all Cry toxins
tested individually, with RR50 of 30.2-fold, 13.7-fold and 6.3-fold
for Cry4A, Cry4B and Cry11 respectively. When Cry4A and Cry4B
were tested in mixture, the resistance ratio of the LiTOX strain
fell to sixfold and was significantly lower than the resistance ratio
observed for Cry4A, but not significantly lower than that observed
for Cry4B. Finally, a moderate but significant RR50 of threefold
to Cyt1A was observed for the LiTOX strain compared with the
susceptible Bora-Bora strain