Scientific Reports 6: Article number: 23351; published online: 30 March 2016; updated: 22 April 2016

This Article contains typographical errors in a grant number in the Acknowledgements section.

“This work was supported by grants National Natural Science Foundation of China (331470877, 81172811),”

should read:

“This work was supported by grants National Natural Science Foundation of China (31470877, 81172811),”