Isolation and Identification of a Wheat Gene Encoding a bHLH Domain Protein, Which Negatively Regulates Chlorophyll Biosynthesis in .

Chlorophyll biosynthesis plays a vital role in chloroplast development and photosynthesis in plants. In this study, we identified an orthologue of the rice gene ( L., Tapetum Degeneration Retardation) in wheat ( L.) called () by sequence comparison. TaTDRL encodes a putative 557 amino acid protein with a basic helix-loop-helix (bHLH) conserved domain at the C-terminal (295-344 aa). The TaTDRL protein localised to the nucleus and displayed transcriptional activation activity in a yeast hybrid system. was expressed in the leaf tissue and expression was induced by dark treatment. Here, we revealed the potential function of gene in wheat by utilizing transgenic plants TaTDRL overexpressing (TaTDRL-OE) and TaTDRL-EAR (EAR-motif, a repression domain of only 12 amino acids). Compared with wild-type plants (WT), both TaTDRL-OE and TaTDRL-EAR were characterized by a deficiency of chlorophyll. Moreover, the expression level of the chlorophyll-related gene () in TaTDRL-OE and TaTDRL-EAR was lower than that of WT. We found that TaTDRL physically interacts with wheat Phytochrome Interacting Factor 1 (PIF1) and Arabadopsis PIF1, suggesting that TaTDRL regulates light signaling during dark or light treatment. In summary, TaTDRL may respond to dark or light treatment and negatively regulate chlorophyll biosynthesis by interacting with AtPIF1 in transgenic .