Abstract
Establishment of proper polarities along the adaxial-abaxial, proximodistal, and medial-lateral axes is a critical step for the expansion of leaves from leaf primordia. It has been shown that the MYB domain protein, ASYMMETRIC LEAVES1/ROUGH SHEATH2/PHANTASTICA (collectively named ARP) plays an important role in this process. Loss of function of ARP leads to severe leaf polarity defects, such as abaxialized or needle-like leaves. In addition to its role in leaf polarity establishment, we have recently shown that the Medicago truncatula ARP gene, MtPHAN, also plays a role in leaf petiole identity regulation. We show that a mutation of MtPHAN results in petioles acquiring characteristics of the motor organ, pulvinus, including small epidermal cells with extensive cell surface modifications and altered vascular tissue development. Taken together, our results reveal a previously unidentified function of ARP in leaf development.
Disclosure of Potential Conflicts of Interest
No potential conflicts of interest were disclosed.
Acknowledgments
The authors wish to thank members of the Chen laboratory for helpful discussions and Colleen Elles for excellent greenhouse assistance. This work was supported by The Samuel Roberts Noble Foundation.