A label‐free differential proteomics analysis reveals the effect of melatonin on promoting fruit ripening and anthocyanin accumulation upon postharvest in tomato

Abstract

To better understand the function of melatonin in tomato fruit ripening and quality improvement, a label-free quantitation method was used to investigate the proteins that differ between the control (CK) and 50 μm melatonin treatment (M50) fruits. Proteomics data identified 241 proteins that were significantly influenced by melatonin. These proteins were involved in several ripening-related pathways, including cell wall metabolism, oxidative phosphorylation, carbohydrate, and fatty acid metabolism. Moreover, the application of exogenous melatonin increased eight proteins that are related to anthocyanin accumulation during fruit ripening. Additionally, the affected protein levels correlated with the corresponding gene transcript levels. Further, the total anthocyanin content from M50 increased by 52%, 48%, and 50% at 5, 8, and 13 DAT (day after melatonin treatment), respectively. The melatonin-mediated promotion of fruit ripening and quality might be due to the altered proteins involved in processes associated with ripening. In this work, we indicated that a senescence-related protein was downregulated in the M50 fruit, while a cell apoptosis inhibitor (API5) protein was upregulated. In addition, peroxidases (POD9, POD12, peroxidase p7-like) and catalase (CAT3) significantly increased in the M50 fruits. Based on the previous studies and our data, we inferred that melatonin might be positively related to fruit ripening but negatively related to fruit senescence. This research provides insights into the physiological and molecular mechanisms underlying melatonin-mediated fruit ripening as well as the anthocyanin formation process in tomato fruit at the protein concentration level, and we reveal possible candidates for regulation of anthocyanin formation during fruit ripening.

Flavonoids inhibit both rice and sheep serotonin N‐acetyltransferases and reduce melatonin levels in plants

“…SNAT (which catalyzes the penultimate biosynthetic step) is expressed in both chloroplasts and mitochondria whereas the enzyme catalyzing the ultimate step ( N ‐acetylserotonin methyltransferase [ASMT]) is expressed in both the cytoplasm and chloroplasts . Melatonin protects plants against both biotic and abiotic stresses, and plays roles in plant growth and development . In recent decades, the physiological and biochemical roles of plant melatonin have been studied both pharmacologically and via molecular genetics, but no inhibitors of SNAT or ASMT have been described.…”

Endophytic Bacterium Pseudomonas fluorescens RG11 May Transform Tryptophan to Melatonin and Promote Endogenous Melatonin Levels in the Roots of Four Grape Cultivars

“…Melatonin was first identified in edible plants in 1995 (Dubbels et al, 1995; Hattori et al, 1995), and it was subsequently identified in hundreds of plant species (Burkhardt et al, 2001; Reiter et al, 2005; Okazaki and Ezura, 2009; Murch et al, 2010). Exogenous melatonin can act as a phytoregulator of seed germination (Zhang et al, 2013, 2014), flowering (Kolář et al, 2003), fruit ripening, anthocyanin accumulation (Sun et al, 2016), root system architecture (Pelagio-Flores et al, 2012), chlorophyll preservation, and leaf senescence (Zhang et al, 2016). It is also a powerful antioxidant that directly decreases the levels of ROS or indirectly modulates antioxidant enzyme activities (Posmyk et al, 2008, 2009; Arnao and Hernández-Ruiz, 2009; Nawaz et al, 2016).…”

High Concentration of Melatonin Regulates Leaf Development by Suppressing Cell Proliferation and Endoreduplication in Arabidopsis

“…The extensive transcriptional reprogramming is consistent with the wide participation of melatonin in plant stress resistance, at least partially [11,12,13,14,15,16,17,18,19,20,21,22]. On the other hand, melatonin is also involved in several developmental processes of plants, including seed germination, shoot development, root growth and architecture, flowering and fruit ripening [23,24,25,26,27,28,29]. To our knowledge, this is the first study to report the involvement of melatonin in leaf development.…”

“…In the most recent 20 years, studies on melatonin have revealed that it functions as an important messenger in regulating the response of plant to both abiotic and biotic stresses, including cold, heat, salt, drought, cadmium, zinc sulfate, and pathogen attacks [11,12,13,14,15,16,17,18,19,20,21,22]. Melatonin also participates in the processes of root growth and architecture, shoot development, flowering, seed germination and fruit ripening [23,24,25,26,27,28,29]. In addition, the auxin-like effects of melatonin are controversial [23,30,31,32,33,34,35,36,37].…”