Acknowledgements

We acknowledge the confocal core facility at National Cheng Kung University for fluorescence observations and thanks for Ya-Chi Yu for generating transgenic plants and fusion protein observations. We also appreciate constructive comments from Dr. Peter B Goldsbrough. This work was financially supported by grants from the Ministry of Science and Technology, Taiwan (MOST 104-2311-B-006-004-MY3; MOST 108-2314-B-006 -077 -MY3) and from the DAAD/NSC PPP program (NSC PPP Germany 106-2911-I-006-506) to WJG and (DAAD PPP Taiwan 57320939) to HEN.