Plasma membrane localization of the type I H+-PPase AVP1 in sieve element-companion cell complexes from Arabidopsis thaliana

► First evidence (immunohistochemical and immunogold labeling) consistent with a PM localization of the type I H+-PPase in Arabidopsis thaliana. ► Data show that the type I H+-PPase localizes to the PM of sieve element-companion cell complexes of source leaves in Arabidopsis thaliana. ► 12 nm gold colloid particles used to label the H+-PPase localized at the same membrane and in close proximity to the 20 nm gold particles that label PIP1 in SE-CC complexes. ► Epifluorescence experiments show a strong florescence signal corresponding to AVP1 in xylem vessels of Arabidopsis primary vein.