P. emaculata urediniospore interactions with nonhost and host monocot plant species. Detached leaves of each species were arranged in Petri plates and spray-inoculated with P. emaculata urediniospores. After 72 h, leaves were immersed in 1x PBS containing 10 μg/ml of WGA-Alexa-fluor-488. Epifluorescence micrograph visualized under an epifluorescence microscope showed pre-infection structures of P. emaculata on foxtail millet (a), corn (b), sorghum (c), barley (d), rice (e), Brachypodium (Bd21) (f) and switchgrass (g). Germinated urediniospores on the leaf surface were evaluated for oriented growth (O), appressoria formation (Ap) on stomata (St), haustoria formation (H) and sporulating rust pustules (S). Boxes below each figure represent absence (red) and presence (green) of studied pre-infection structures of P. emaculata; scale bar = 50 μm.