The effect of changes in temperature on Pst development in seedlings of the wheat line UC1041 - Yr36. A) Mean leaf area (%) covered in uredia 18 dpi on UC1041 -Yr36 seedlings. Leaves were inoculated with Pst isolate 08/21 and kept at the original temperature regime of 12°C/18°C or 12°C/25°C pre and post inoculation (dark grey) or transferred to the other temperature regime post-inoculation (light grey). Mean values (± 1 standard error) were obtained from up to 50 fields of view in three independent experiments. Different letters indicate statistically significant differences (P < 0.01). B-C) Microscopic characterisation of Pst development as categorised by the extent of hyphal colonisation. B) Illustration of Pst hyphal abundance, with each category of abundance being represented by different cross-hatching (upper panel). C) Frequency of occurrence of each category in each temperature treatment. Mean values for each category were obtained from three biological replicates.