The wheat MYB transcription factor TaMYB18 regulates leaf rolling in rice.

Leaf rolling is an important agronomic trait in crop breeding. Moderate leaf rolling maintains the erectness of leaves and minimizes shadowing between leaves, leading to improved photosynthetic efficiency. Although some genes controlling leaf rolling have been isolated from rice and other plant species, few studies have examined leaf rolling in wheat. In the present study, the leaf rolling regulator gene, TaMYB18, was identified in a large-scale transgene project involving the transformation of 1455 wheat transcription factor genes into rice. Three homologous sequences of TaMYB18 were isolated from hexaploid wheat and localized to chromosomes 5A, 5B and 5D, respectively. TaMYB18, an R2R3-MYB transcription factor, localized to the nucleus. TaMYB18 overexpression induced leaf rolling in transgenic rice. Additionally, the three members of TaMYB18 exhibited functional redundancy in rice. Furthermore, the function of TaMYB18 in regulating leaf rolling in rice was a dose-dependent. Taken together, these results indicate that TaMYB18 may play an important role in the regulation of leaf development.