Coordination of Phytomelatonin and Salicylic Acid Signalling in Stomatal Closure

Xue Li; Lin Xiao; Yanjie Song; Xingyang Wei; Zed Rengel; Yanli Chen; Kunzhi Li; Qi Chen

doi:10.1111/pce.70048

Coordination of Phytomelatonin and Salicylic Acid Signalling in Stomatal Closure

Plant Cell Environ. 2025 Jul 9. doi: 10.1111/pce.70048. Online ahead of print.

Authors

Xue Li^{1

2}, Lin Xiao¹, Yanjie Song^{1

2}, Xingyang Wei¹, Zed Rengel^{3

4}, Yanli Chen¹, Kunzhi Li¹, Qi Chen^{1

2}

Affiliations

¹ Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China.
² State Key Laboratory of Plant Diversity and Specialty Crops, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Yunnan, China.
³ UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Perth, Western Australia, Australia.
⁴ Institute for Adriatic Crops and Karst Reclamation, Split, Croatia.

PMID: 40635321
DOI: 10.1111/pce.70048

Abstract

Phytomelatonin (PMT) and salicylic acid (SA) play crucial roles in stomatal closure and immune regulation, yet their regulatory mechanisms are not fully understood. Here, we found that SA-induced stomatal closure and ROS production are dependent on the phytomelatonin receptor 1 (PMTR1) via regulating the expression of genes associated with cell wall peroxidases PRX33 and PRX34. Exogenous melatonin (exMT) induces the expression of genes related to SA biosynthesis (ICS1, PBS3), the receptor NPR1, as well as the effector transcription factors TGA1-3. Furthermore, exMT promotes the nuclear localisation of NPR1 through NO and GSH signalling in a PMTR1-dependent manner. Mutants of npr1, as well as tga1, tga2 and tga3, show partial sensitivity to PMTR1-mediated exMT signalling in stomatal closure. Either exMT or SA can significantly increase PMTR1 expression in Col-0, but not in npr1-1 and tga1 mutant plants. TGA1 can directly bind to the promoter elements of PMTR1 and activate its expression. Furthermore, the exMT- and SA-induced stomatal closure plays a vital role in preventing bacterial invasion in a PMTR1-dependent manner. Collectively, the results presented here demonstrate the coordination of PMTR1 and NPR1 in the regulation of PMT and SA signals in stomatal closure and immunity.

Keywords: NPR1; PMTR1; Phytomelatonin; TGA1; salicylic acid.

Grants and funding

This study was supported by the National Natural Science Foundation of China (32370315 and 31960624), and the Natural Science Foundation of Yunnan Province (202201AV070008, 202101AS070027, and 202101BE070001-047).