Figure 8
Chlamydospores produced by Zymoseptoria tritici are more tolerant to stress than blastospores and pseudohyphae. Survival rate (%) was estimated based upon the number of colonies formed after exposure to the stressful environment compared to the number of colonies formed in the control environment after seven days. All stress assays were performed using different morphotypes from the 1A5 strain. (A) Blastospores, pseudohyphae and chlamydospore cells were kept for 1, 3, 5, and 10 days in a sealed box containing anhydrous silica gel to produce a dry environment. This simulated drought stress affected blastospore and pseudohyphae survival over time. Chlamydospores were less affected and exhibited a survival rate of 50% after 10 days under drought stress. (B) The same three morphotypes were subjected to a cold shock. Blastospores, pseudohyphae, and chlamydospores were submerged in liquid nitrogen for 1, 2, and 3 minutes at −196 °C. Only chlamydospores survived this cold stress. (C) The same three morphotypes were subjected to heat stress based on incubation for 24 hours at 30 °C, 35 °C or 40 °C. Blastospores and chlamydospores were equally affected at 30 °C. The incubation at 35 °C killed all the blastospores, while chlamydospore survived at a 12% rate, double the rate observed for pseudohyphae (6%). No colonies were observed after incubation at 40 °C. One star indicates that the adjusted p value is <0.05, two stars indicates that the p value is <0.005, and three stars indicates that the p value is <0.0005. NS indicates no significant difference.
