Figure 5.
Attenuated pathogenicity in the cna1 or the cnb1 gene-deficient T. asahii mutants against silkworms. (a,b) The T. asahii parent strain (Parent; 2.9 × 105 cells/larva), the cna1 gene-deficient mutant (∆cna1; 7.4 × 105 cells/larva), the revertant from ∆cna1 (CNA1; 4.2 × 105 cells/larva), the cnb1 gene-deficient mutant (∆cnb1; 6.1 × 105 cells/larva), or the revertant from ∆cnb1 (CNB1; 7.1 × 105 cells/larva) were injected into the silkworm hemolymph and the silkworms were incubated at 37 °C. Silkworm survival was monitored for 72 h. The significance of differences between the parent strain group and the cnb1 gene-deficient mutant groups was calculated by the log-rank test based on the curves by the Kaplan–Meier method. P < 0.05 was considered significant. n = 10/group. (c,d) Number of surviving silkworms at conditions under 37 °C was determined at 48 h after administration of the fungal cells (50 to 1.2 × 106 cells/larva) into the silkworm hemolymph. Surviving and dead silkworms are indicated as 1 and 0, respectively. n = 4/group. Curves were drawn from combined data of 2–3 independent experiments by a simple logistic regression model.