DYT 1 directly regulates the expression of TDF 1 for tapetum development and pollen wall formation in A rabidopsis

Summary The tapetum plays a critical role during the development and maturation of microspores. DYSFUNCTIONAL TAPETUM 1 ( DYT 1 ) is essential for early tapetal development. Here, we determined that the promoter region (−550 to −463 bp) contains indispensable cis ‐elements for DYT 1 expression. Although DYT 1 transcripts can be detected in both meiocytes and tapetal cells, localization of DYT 1– GFP demonstrated that DYT 1 is strictly located in tapetal cells during microsporogenesis. Chromatin immunoprecipitation ( C hIP) analysis revealed that DYT 1 directly binds the promoter region of D efective in T apetal D evelopment and Function 1 ( TDF 1 ), a transcription factor essential for tapetum development. When TDF 1 driven by the DYT 1 promoter is expressed in a dyt1 mutant, the expression of the transcription factors AMS , MS 188 / MY B80 , TEK and MS 1 and the pollen wall‐related genes are restored. Although the pollen wall is not formed and the microspores are ruptured, DIOC 2 staining showed that fatty acids, the precursors of the pollen wall, were synthesized in the transgenic lines. These results indicate that DYT 1 regulates the expression of AMS , MS 188/ MYB 80 , TEK and MS1 for pollen wall formation, primarily via TDF 1 .