A Golgi-Localized Manganese Transporter Functions in Pollen Tube Tip Growth to Control Male Fertility in Arabidopsis

Abstract Manganese (Mn) serves as an essential cofactor for many enzymes in various compartments of a plant cell. Allocation of Mn among various organelles thus plays a central role in Mn homeostasis to support metabolic processes. We report identification of a Golgi-localized Mn transporter (named PML3) that is essential for rapid cell elongation in young tissues such as emerging leaves and pollen tube. In particular, the pollen tube defect in the pml3 loss of function mutant caused severe reduction in seed yield, a critical agronomic trait. Further analysis suggested loss of pectin deposition in the pollen tube might cause pollen tube burst and slow elongation, leading to decreased male fertility. As Golgi apparatus serve as the major hub for biosynthesis and modification of cell wall components, the PML3 may function in Mn homeostasis of this organelle thereby controlling metabolic and/or trafficking processes required for pectin deposition in the rapidly elongation cells.