Characterization of endo-PM properties using genetically encoded fluorescent lipid sensors. (A–E) Localization of different lipids in the vegetative cell of Arabidopsis mature pollen through lipid biosensors. Confocal imaging allowed visualization of different lipid biosensors (Simon et al., 2014; Platre et al., 2018) expressed in the vegetative cell of pollen under the pUBQ10 promoter. PA, PS, PI3P, Pi(4,5)P₂, and PI4P. (F) Confocal imaging of Arabidopsis mature pollen showing subcellular localization of a charge biosensor (KA1^Kcc4p) which consists in a folded domain that lacks stereospecificity and associates nonspecifically with anionic lipids (Simon et al., 2016). (G) Quantification of fluorescence intensity for biosensors at the endo-PM as compared with the fluorescence intensity at PM of vegetative cell (endo-PM/PM fluorescence ratio; mean ± SD). n = number of mature pollens analyzed. All scale bars = 20 µm.