Auxin response factors (ARFs) play a central role in plants as transcriptional factors in response to auxin. The Arabidopsis ARF8 gene is a light-inducible gene and ARF8 protein might control auxin homeostasis in a negative feed-back fashion through regulation of GH3 gene expression. In a double mutant designated infertile line including arf8-1 (a T-DNA insertion mutant of ARF8), we isolatedfertility1-1 (fer1-1), a mutant of Fer1, which acts synergistically with ARF8 to control the development of the anther and filament in Arabidopsis. Genetics analysis has demonstrated thatfer1-1 is a T-DNA insertion line,indicating that Fer1 might be cloned by inverse polymerase chain reaction (PCR) or the TAIL-PCR approach.Phenotypic identification and molecular analysis offer1-1 and the infertile line will be helpful to characterize the function of Fer1, to further study the function of ARF8, and to reveal the molecular mechanism underlying the interaction of Fer1 and ARF8 in controlling development of the anther and filament.