ER-localized auxin transporter PIn8 regulates auxinhomeostasis and male gametophyte developmentin Arabidopsis

摘要

Auxin is a key coordinative signal required for many aspects of plant development and itslevels are controlled by auxin metabolism and intercellular auxin transport. Here we find that amember of PIn auxin transporter family, PIn8 is expressed in male gametophyte of Arabidopsisthaliana and has a crucial role in pollen development and functionality. Ectopic expression insporophytic tissues establishes a role of PIn8 in regulating auxin homoeostasis and metabolism.PIn8 co-localizes with PIn5 to the endoplasmic reticulum (ER) where it acts as an auxintransporter. Genetic analyses reveal an antagonistic action of PIn5 and PIn8 in the regulationof intracellular auxin homoeostasis and gametophyte as well as sporophyte development.our results reveal a role of the auxin transport in male gametophyte development in whichthe distinct actions of ER-localized PIn transporters regulate cellular auxin homoeostasis andmaintain the auxin levels optimal for pollen development and pollen tube growth.