Molecular hydrogen–induced salinity tolerance requires melatonin signalling inArabidopsis thaliana

Abstract

Melatonin (MT) plays positive roles in salinity stress tolerance. However, the upstream signalling components that regulate MT are poorly understood. Here, we report that endogenous MT acts downstream of molecular hydrogen (H2) in the salinity response in Arabidopsis. The addition of hydrogen‐rich water and expression of the hydrogenase1 gene (CrHYD1) from Chlamydomonas reinhardtii increased endogenous H2 and MT levels and enhanced salinity tolerance. These results were not observed in the absence of serotonin N‐acetyltransferase gene (SNAT). H2 increased the levels of SNAT transcripts in the wild‐type and CrHYD1 lines, which had lower Na+/K+ ratios and higher levels of ion transport–related gene transcripts. These changes were not observed in atsnat/CrHYD1‐4 hybrids. The increased MT‐dependent Na+ extrusion observed in the CrHYD1 plants resulted, at least in part, from enhanced Na+/H+ antiport across the plasma membrane. The endogenous H2‐induced MT‐dependent regulation of ion and redox homeostasis was impaired in the atsnat/CrHYD1‐4 hybrids. Taken together, these results demonstrate that MT‐induced salinity tolerance is induced by a H2 signalling cascade that regulates ion and redox homeostasis in response to salinity.

Degradation of Carbendazim by Molecular Hydrogen on Leaf Models

“…In the previous reports, the expression of hydrogenase1 gene from Chlamydomonas reinhardtii ( CrHYD1 ) in Arabidopsis represents an interesting method to assess the functions of endogenous production of H 2 in plant cells, since molecular hydrogen derived from CrHYD1 expression could modify the stomatal closure [ 20 ] and improve salinity tolerance [ 19 ]. Here, compared to those in the wild-type (WT) with or without being transformed with the empty vector (EV), six CrHYD1 lines not only showed increased H 2 production in the presence of CAR ( Figure S6 ), but importantly, displayed the lower residues of CAR in leaves, especially CrHYD1-3 , CrHYD1-5 , and CrHYD1-6 ( Figure 6 A), and similar beneficial roles of endogenous H 2 were discovered according to the changes in stomatal bioassays [ 20 ] and salinity phenotypic analysis [ 19 ]. Under the identical treatments, contrasting changes in endogenous GSH were also observed ( Figure 6 B), thus reflecting the possible negative correlation between CAR residues and GSH contents.…”

“…However, CHT was hardly absorbed by plants compared with CAR [ 18 ]. Genetic evidence showed that the expression of the hydrogenase1 gene ( CrHYD1 ) from Chlamydomonas reinhardtii not only increased endogenous H 2 production, but also confers Arabidopsis tolerance against salinity [ 19 ] and drought stress [ 20 ]. Additionally, H 2 could influence nitric oxide [ 21 ], abscisic acid [ 22 ], auxin [ 23 ], melatonin [ 19 ], and glutathione [ 24 ] signaling in plants.…”

Melatonin-Mediated Abiotic Stress Tolerance in Plants

“…Salt stress has become a severe global problem, limiting agricultural production and leading to substantial economic losses worldwide ( Su et al, 2021 ). Salt has two detrimental effects on plants: osmotic stress and ion poisoning ( Van Zelm et al, 2020 ).…”

Hydrogen Nanobubble Water Delays Petal Senescence and Prolongs the Vase Life of Cut Carnation (Dianthus caryophyllus L.) Flowers

“…Interestingly, the production of H 2 has been observed in plants under the normal or stressed conditions [ 10 , 11 , 12 ], although its detailed synthetic pathway (s) are not fully elucidated. Further studies have revealed that H 2 played an important role in defense responses of plants to abiotic stresses [ 13 , 14 , 15 ], plant growth [ 16 ], and secondary metabolism [ 17 ]. H 2 was beneficial to postharvest preservation of fruits (kiwifruit [ 18 , 19 ] and tomato [ 20 ]) and cut flowers (rose [ 21 ], lily [ 22 ], and Lisianthus [ 23 ]).…”