Melatonin may increase disease resistance and flavonoid biosynthesis through effects on DNA methylation and gene expression in grape berries

Abstract

Background Melatonin can regulate plant growth, development and biotic responses by causing global changes in gene expression; however, the melatonin-induced changes in gene expression via the modification of DNA methylation remain unclear in plants. Results A total of 1,169,852 and 1,008,894 methylated cytosines (mCs) were identified in the control and melatonin-treated grape berries, respectively, and mCs occurred primarily at CG sites, followed by CHG sites and CHH sites. Compared to the control, melatonin treatment broadly decreased methylation levels at CHG and particularly CHH sites in various gene regions. Melatonin treatment generated a total of 25,125 differentially methylated regions (DMRs), which included 6517 DMR-associated genes. RNA-Seq demonstrated that 2479 genes were upregulated, and 1072 genes were repressed by melatonin treatment. The evaluation of the interconnection of the DNA methylome and transcriptome identified 144 genes showing a negative correlation between promoter methylation and gene expression, which were primarily related to biotic stress responses and flavonoid biosynthesis. Additionally, the application of 5́-azacytidine and melatonin led to similar effects on mycelial growth of B. cinerea, berry decay rate and flavonoid biosynthesis. Moreover, EDS1 was used to show that melatonin increased gene expression by decreasing promoter methylation levels. Conclusion Our results demonstrated that melatonin broadly decreased DNA methylation and altered gene expression in grape berries. We propose that melatonin increases disease resistance and flavonoid biosynthesis by decreasing the methylation levels of the promoters of the genes involved.

Melatonin-induced DNA demethylation of metal transporters and antioxidant genes alleviates lead stress in radish plants

“…3a, b and S3a–c ). These results agreed with those found in grape berries, which showed that exogenous melatonin treatment decreased the methylation levels of various gene regions in the CHG and CHH contexts 40 . It was reported that the DNA demethylase DML2 was downregulated under cold stress in tomato, which resulted in the hypermethylation of the promoter and silencing of genes involved in the biosynthesis of flavor volatiles 41 .…”

Melatonin alters the secondary metabolite profile of grape berry skin by promoting VvMYB14-mediated ethylene biosynthesis

“…7C, D ). Additionally, our recent study revealed that MT increased the expression of another STS gene by decreasing its promoter methylation 33 . Therefore, STSs may represent a key point in the pathway regarding the regulation of resveratrol by MT or MT via ethylene.…”

Multifaceted Chromatin Structure and Transcription Changes in Plant Stress Response

“…tritici ( Bgt ), the upregulation of a pathogenesis-related defense gene AeGlu is attributed to CHH hypomethylation in the promoter [ 147 ]. The increased transcription of ENHANCED DISEASE SUSCEPTIBILITY1 ( EDS1 ) in melatonin-treated grape ( Vitis vinifera ) berries with enhanced resistance to the necrotrophic fungus Botrytis cinerea ( B. cinerea ) also correlates with its decreased promoter methylation level [ 148 ].…”