We would like to thank Prof. Yan Guo (College of Biological Sciences, China Agricultural University) and Lei Yao (Beijing Ago-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences) for providing Aequorin-expressing transgenic Arabidopsis seeds, pYBA1137 and pYBA1143 plant expression vectors. We are grateful to Prof. Godelieve Gheysen from Ghent University (BE) for her scientific advices and for editing the manuscript. Funding. This project was supported by the Natural Science Foundation of China (31571988), the Natural Science Foundation of China (31801716), the Natural Science Foundation of China (31672012), and the Special Fund for Agro-scientific Research in the Public Interest (201503114).