Arabidopsis FAX1mediated fatty acid export is required for the transcriptional regulation of anther development and pollen wall formation

Key Message The mutation ofFAX1(Fatty Acid Export 1) disrupts ROS homeostasis and suppresses transcription activity ofDYT1-TDF1-AMS-MS188genetic network, leading to atypical tapetum PCD and defective pollen formation inArabidopsis. Fatty acids (FAs) have multiple important biological functions and exert diverse cellular effects through modulating Reactive Oxygen Species (ROS) homeostasis.Arabidopsis FAX1(Fatty Acid Export 1) mediates the export of de novo synthesized FA from chloroplast and loss of function ofFAX1impairs male fertility. However, mechanisms underlying the association ofFAX1-mediated FA export with male sterility remain enigmatic. In this study, by using an integrated approach that included morphological, cytological, histological, and molecular analyses, we revealed that loss of function ofFAX1breaks cellular FA/lipid homeostasis, which disrupts ROS homeostasis and suppresses transcriptional activation of the DYT1-TDF1-AMS-MS188 genetic network of anther development, impairing tapetum development and pollen wall formation, and resulting in male sterility. This study provides new insights into the regulatory network for male reproduction in plants, highlighting an important role of FA export-mediated ROS homeostasis in the process.