Wang Z. Li L. Khan D. Chen Y. Pu X. Wang X. Guan M. Rengel Z. Chen Q. text xx 9999 monographic und

electronic

Reactive oxygen species (ROS) and nitric oxide (NO) are important signaling molecules regulating stomatal movements in plants. Melatonin (N-acetyl-5-methoxytryptamine) was found to induce stomatal closure via phytomelatonin receptor 1 (PMTR1)-mediated activation of ROS production. Here, we evaluated the interaction between ROS and NO in the melatonin-induced stomatal closure in Arabidopsis. The results showed that the exogenous melatonin-induced stomatal closure and NO production were abolished by carboxy-PTIO (cPTIO, a NO scavenger). Additionally, the mutant lines nitrate reductase 1 and 2 (nia1nia2) and NO-associated 1 (noa1) did not show melatonin-induced stomatal closure, indicating that the melatonin-mediated stomatal closure is dependent on NO. The application of H2O2 induced the NO production and stomatal closure in the presence or absence of melatonin. However, the melatonin-induced NO production was impaired in the rhohC and rbohD/F (NADPH oxidase respiratory burst oxidase homologs) mutant plants. Furthermore, the ROS levels in nia1nia2 and noa1 did not differ significantly from the wild type plants, indicating that NO is a downstream component in the melatonin-induced ROS production. Exogenous melatonin did not induce NO and ROS production in the guard cells of pmtr1 mutant lines, suggesting NO occurs downstream of ROS in the PMTR1-mediated stomatal closure in Arabidopsis. Taken together, the results presented here suggest that melatonin-induced stomatal closure via PMTR1-mediated signaling in the regulation of ROS and NO production in Arabidopsis. © 2023 Elsevier GmbH ARABIDOPSIS THALIANA MELATONIN NITRIC OXIDE PMTR1 ROS STOMATAL CLOSURE https://drive.google.com/file/d/1Ldm6pMSdx2JkVbjxeyc04jy-2L-gwnHm/view?usp=drivesdk https://drive.google.com/file/d/1Ldm6pMSdx2JkVbjxeyc04jy-2L-gwnHm/view?usp=drivesdk 250602 20260521091756.0