Figure 4.

Spore survival assays of different M. robertsii strains following UV-B, heat and low temperature treatment. Germination rate of conidia from the 3 strains at 16 h (A) and 24 h (B) after UV-B, heat and low temperature exposure. Conidia of the 3 strains (WT, ∆MrUBI4, and Comp) were either UV-B irradiated at 100 μJ·cm⁻² or heated at 40 °C (and low temperature at 4 °C) for 90 min. Germination rates were determined after inoculation on PDA plates at 25 °C for 16 and 24 h. (C) Relative expression analysis of heat stress- and DNA damage response-related genes in conidia under thermal- and UV-treated stress. (D) Relative expression analysis of heat stress-related genes in conidia under normal conditions (25 °C for cultivation). **, p < 0.01. WT: wild-type strain, MT: ∆MrUBI4 strain, Comp: complementary strain.