Figure 3.

Effects of ku70 gene-deficiency in the T. asahii MPU129 mutant on growth, morphology, and pathogenicity against silkworms. (a–d) The wild-type (MPU129) and ku70 gene-deficient mutant were inoculated on RPMI-1640 medium and Sabouraud medium and incubated at 27 °C or 37 °C. Absorbance 630 nm of the culture was monitored. Data are shown as means ± standard error of the mean (SEM). (e) The wild-type (MPU129) and ku70 gene-deficient mutant were incubated at 2 days after inoculation and observed with a microscope. (f–h) Saline, T. asahii MPU129 (WT), or the ku70 gene-deficient mutant (∆ku70) [1.1 × 10⁴ cells/larva (f), 2.2 × 10³ cells/larva (g), 4.4 × 10² cells/larva (h)] were injected into the silkworm hemolymph and incubated at 37 °C. The survival of the silkworms was monitored for 74 h. The significance of differences between groups in silkworm infection experiments was calculated by the log-rank test based on the curves by the Kaplan–Meier method. NS Not significant (P > 0.05). n = 10/group.