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Enzyme kinetics of OsSNAT3. SNAT activity as a function of (A) pH and (B) temperature, and determination of Km and Vmax values of OsSNAT3 using (C) serotonin and (D) 5-methoxytryptamine (5-MT) as substrates. Recombinant purified OsSNAT3 (1 µg) was assayed in the presence of different serotonin and 5-MT concentrations for 1 h at different temperatures and pH values, followed by high-performance liquid chromatography detection of N-acetylserotonin (NAS) and melatonin. Kinetic values of Km and Vmax were determined using Lineweaver–Burk plots. Values are presented as the mean ± SD (n = 3). nd, not detected.
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The study of the mechanisms by which melatonin protects against cadmium (Cd) toxicity in plants is still in its infancy, particularly at the molecular level. In this study, the gene encoding a novel serotonin N-acetyltransferase 3 (SNAT3) in rice, a pivotal enzyme in the melatonin biosynthetic pathway, was cloned. Rice (Oryza sativa) OsSNAT3 is the...
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Melatonin is recognized as a crucial plant hormone due to its significant role in plant development, growth promotion, enhancing antioxidant activity, and stress resistance. Soybean is one of the most important crops globally. To date, three SNAT genes have been cloned in Arabidopsis and rice; however, only one gene, GmSNAT1, has been characterized...
Introduction
Melatonin, a tryptophan-derived indoleamine metabolite with important roles in plant growth and defense, has recently been regarded as a new plant hormone. Maize is one of the most important cereal crops in the world. Although the melatonin receptor gene, ZmPMTR1, has already been identified, the genetic basis of melatonin biosynthesis...
Citations
... OsSNAT3 has also been identified and its overexpression lines showed higher melatonin levels. The SNAT3-OE lines were more tolerant in cadmium stress (Lee and Back 2024). Recently, AtSNAT6 was also cloned in Arabidopsis, and its homologous gene, ZmSNAT3, was identified in maize (Wang et al. 2022;Guo et al. 2024). ...
Melatonin is recognized as a crucial plant hormone due to its significant role in plant development, growth promotion, enhancing antioxidant activity, and stress resistance. Soybean is one of the most important crops globally. To date, three SNAT genes have been cloned in Arabidopsis and rice; however, only one gene, GmSNAT1, has been characterized in soybeans. In this study, members of the GmGNAT family were identified through genome‐wide analysis. Two candidate GmSNAT genes (GmSNAT3.1 and GmSNAT3.2) were selected based on phylogenetic tree analysis and exhibited highly similar protein tertiary structures to ZmSNAT3. Furthermore, the functionality of these two GmSNAT genes was confirmed for synthesizing N‐acetylserotonin or melatonin using serotonin or 5‐methoxytryptamine as substrates in vitro. RNA‐seq data indicated that the transcription levels of GmSNAT3.1 and GmSNAT3.2 were downregulated under conditions of dehydration and salt stress. Additionally, SNAT3 genes from other leguminous plants were identified through homology analysis with GmSNAT genes. This study elucidates the role of SNAT genes in soybeans and establishes a foundation for further exploration into the physiological functions of melatonin within legume plants.
... The mechanisms through which MT safeguards plants against cadmium (Cd) toxicity are still not fully understood, particularly at the molecular level. Lee et al. [8] successfully identified and cloned a novel serotonin N-acetyltransferase 3 (SNAT3) gene in rice (Oryza sativa); this gene is a pivotal enzyme involved in MT biosynthesis. OsSNAT3 converts serotonin and 5-methoxytryptamine into N-acetylserotonin and MT, respectively. ...
Plants face many abiotic stresses that significantly impact their growth and survival, requiring intricate mechanisms in order to adapt and thrive [...]
... In recent years, microbial heterologous synthesis of melatonin has emerged as a research hotspot due to its cost-effectiveness and sustainability. Additionally, biotechnological advancements in rice have demonstrated significant potential to enhance the efficiency of melatonin synthesis [51]. This approach offers a novel strategy for the development of vaccines against the novel coronavirus. ...
This paper aims to review the research progress on the processing and utilization of functional rice and explore its potential to enhance human health. The research progress in the processing and utilization of colored rice, low-protein rice, high-resistant starch rice, micronutrient-enriched rice, and bioreactor rice was systematically analyzed through a comprehensive literature review. The impact of various processing techniques on the retention of nutritional components in functional rice was also discussed. This study found that functional rice exhibits great potential in terms of nutritional value, health effects, and market demand. However, issues such as the loss of bioactive components during processing, the maintenance of specific agronomic traits, and market acceptance still need to be addressed. The research and development of functional rice are significant for enriching people’s dietary choices and addressing global malnutrition and chronic disease problems. Future efforts should focus on further optimizing processing techniques and utilizing genetic engineering and molecular breeding technologies to enhance the nutritional value and agronomic traits of functional rice, thus meeting market demands and health objectives.
... As for the real-time PCR analysis, a Mic qPCR Cycler system (Bio Molecular Systems, Coomera, Queensland, VIC, Australia) with the Luna Universal qPCR Master Mix (New England Biolabs, Ipswich, MA, USA) was utilized. The expression of genes was analyzed using Mic's RQ software v2.2 (Bio Molecular Systems) and normalized to UBQ5 as described previously [28]. ...
... As shown in Figure 3B, the recombinant SlSNAT exhibited SNAT-specific enzyme activity of 7.1 pkat/mg protein, which was similar to the activity reported previously for an archaeon SNAT (6.7 pkat/mg protein) [20]. The SNAT enzyme activity of SlSNAT was 1.8-fold higher than that of E. coli RimI [21] but 4.7-fold lower than that of rice SNAT3 [28]. All SNAT enzymes from animals or plants can accept many other amines as substrates [16,30]. ...
... A novel archaeal SNAT clade was identified showing no apparent sequence identity to either animal AANAT or plant SNAT. Archaeal SNAT orthologues have recently been cloned from human [18], E. coli [21], and rice [28]. In this study, an orthologue of archaeal SNAT from S. lemnae was cloned, and its product was characterized. ...
Serotonin N-acetyltransferase (SNAT) is a pivotal enzyme for melatonin biosynthesis in all living organisms. It catalyzes the conversion of serotonin to N-acetylserotonin (NAS) or 5-methoxytrypytamine (5-MT) to melatonin. In contrast to animal- and plant-specific SNAT genes, a novel clade of archaeal SNAT genes has recently been reported. In this study, we identified homologues of archaeal SNAT genes in ciliates and dinoflagellates, but no animal- or plant-specific SNAT homologues. Archaeal SNAT homologue from the ciliate Stylonychia lemnae was annotated as a putative N-acetyltransferase. To determine whether the putative S. lemnae SNAT (SlSNAT) exhibits SNAT enzyme activity, we chemically synthesized and expressed the full-length SlSNAT coding sequence (CDS) in Escherichia coli, from which the recombinant SlSNAT protein was purified by Ni²⁺ affinity column chromatography. The recombinant SlSNAT exhibited SNAT enzyme activity toward serotonin (Km = 776 µM) and 5-MT (Km = 246 µM) as substrates. Furthermore, SlSNAT-overexpressing (SlSNAT-OE) transgenic rice plants showed higher levels of melatonin synthesis than wild-type controls. The SlSNAT-OE rice plants exhibited delayed leaf senescence and tolerance against treatment with the reactive oxygen species (ROS)-inducing herbicide butafenacil by decreasing hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels, suggesting that melatonin alleviates ROS production in vivo.
