Melatonin Promotes SGT1-Involved Signals to Ameliorate Drought Stress Adaption in Rice

Abstract

Drought has become one of the environmental threats to agriculture and food security. Applications of melatonin (MT) serve as an effective way to alleviate drought stress, but the underlying mechanism remains poorly understood. Here, we found that foliar spray of 100-µM MT greatly mitigated the severe drought stress-induced damages in rice seedlings, including improved survival rates, enhanced antioxidant system, and adjusted osmotic balance. However, mutation of the suppressor of the G2 allele of skp1 (OsSGT1) and ABSCISIC ACID INSENSITIVE 5 (OsABI5) abolished the effects of MT. Furthermore, the upregulated expression of OsABI5 was detected in wild type (WT) under drought stress, irrespective of MT treatment, whereas OsABI5 was significantly downregulated in sgt1 and sgt1abi5 mutants. In contrast, no change of the OsSGT1 expression level was detected in abi5. Moreover, mutation of OsSGT1 and OsABI5 significantly suppressed the expression of genes associated with the antioxidant system. These results suggested that the functions of OsSGT1 in the MT-mediated alleviation of drought stress were associated with the ABI5-mediated signals. Collectively, we demonstrated that OsSGT1 was involved in the drought response of rice and that melatonin promoted SGT1-involved signals to ameliorate drought stress adaption.

Identification and Functional Analysis of the Caffeic Acid O-Methyltransferase (COMT) Gene Family in Rice (Oryza sativa L.)

“…COMT also catalyzes the methylation of caffeic acid, 5-hydroxypinobanksyl aldehyde, and 5-hydroxypinobanksyl alcohol to generate ferulic acid, mustard aldehyde, and mustard alcohol, respectively, which are involved in the methylation reactions of mustard alcohol (S unit) and pinobanksyl alcohol (G unit) synthesis, and they play a decisive role in the composition of different types of monolignans [ 16 ]. COMT also catalyzes the production of melatonin from N-acetyl-5-hydroxytryptamine [ 17 ], and the level of melatonin content affects plant drought tolerance [ 18 ] and salt tolerance [ 19 ]. The first COMT gene was cloned in Ligusticum chuanxiong , and it was concluded that the COMT gene positively regulates the lignin content [ 20 ].…”

A silicon particle-based courier promotes melatonin-mediated seed tolerance to nickel toxicity in rice

“…6,9,39 ABI5 serves as an important module of stress-induced signals, 76 and has been reported to be involved in MTmediated amelioration effects on seed germination 20 and seedling growth. 18 Herein, mutation of OsABI5 negatively affected the amelioration of pSi-MT on seed germination exposed to Ni toxicity, suggesting the important role of OsABI5 in this process (Fig. 9), which was possibly associated with the crosstalk of phytohormone-mediated signals and ROS-mediated signals.…”

“…Since ABI5 is reported to be involved in melatonin-ameliorated tolerance to abiotic stress, 18,20 we employ the abi5 mutant to test whether the phyto-courier of pSi-MT can work effectively to resist nickel toxicity. Comparisons of the control versus treated seeds in the presence of Ni showed significant decreases of Environmental Science: Nano Paper germination rates in abi5-1 and abi5-2, while under Ni stress, no obvious amelioration of the stress signs could be noticed in the ones treated with pSi and/or pSi-MT in both abi5-1 and abi5-2 (Fig.…”

“…Recently, applications of various chemical molecules are thought to be potential and useful ways to mitigate Ni stress, like melatonin (MT), 4,10 hydrogen sulfide, 5 nitric oxide, 14 and silicon. 6,9,[15][16][17] Amongst them, the effects of MT on plants have been widely studied under various stress conditions, including drought, 18,19 chilling or low temperature, 20 salinity, 12,21 water stress, 22 heavy metal toxicity, 11,[23][24][25] etc. The working concentrations of MT to mitigate stress show species-and growth stage-dependence, but 50 to 200 μM of MT have been demonstrated effectively in many reports.…”

Functional Characterization of Arylalkylamine N-Acetyltransferase, a Pivotal Gene in Antioxidant Melatonin Biosynthesis from Chlamydomonas reinhardtii

“…Moreover, the increase in BR levels caused by endogenous melatonin overproduction induces melatonin biosynthesis by activating the expression of melatonin biosynthetic genes such as tryptophan decarboxylase 1 ( TDC1 ), TDC3 , and tryptamine 5-hydroxylase ( T5H ) [ 64 ] ( Figure 9 ). In sum, the effect of melatonin on seed size and yield [ 17 , 61 ] and stress tolerance [ 65 , 66 ] suggests that the generation of melatonin-rich rice plants by exogenous application [ 64 ] or transgenic approaches [ 4 ] would increase yields and resistance to many biotic and abiotic stresses and enable the production of melatonin-rich foods with health benefits [ 67 ].…”