AUXIN RESPONSE FACTOR17 Directly Regulates for Anther Dehiscence.

The timely release of mature pollen following anther dehiscence is essential for reproduction in flowering plants. AUXIN RESPONSE FACTOR17 (ARF17) plays a crucial role in pollen wall pattern formation, tapetum development, and auxin signal transduction in anthers. Here, we showed that ARF17 is also involved in anther dehiscence. The Arabidopsis () mutant exhibits defective endothecium lignification, which leads to defects in anther dehiscence. The expression of , which encodes a transcription factor important for anther dehiscence, was dramatically down-regulated in the flower buds of Chromatin immunoprecipitation assays and electrophoretic mobility shift assays showed ARF17 directly binds to the promoter. In an ARF17-GFP transgenic line, in which ARF17-GFP fully complements the phenotype, ARF17-GFP was observed in the endothecia at anther stage 11. The GUS signal driven by the promoter was also detected in endothecia at late anther stages in transgenic plants expressing Thus, the expression pattern of both and is consistent with the function of these genes in anther dehiscence. Furthermore, the expression of driven by the promoter successfully restored the defects in anther dehiscence of These results demonstrated that ARF17 regulates the expression of for anther dehiscence. Together with its function in microcytes and tapeta, ARF17 likely coordinates the development of different sporophytic cell layers in anthers. The ARF17-MYB108 pathway involved in regulating anther dehiscence is also discussed.