Metabolomic and Transcriptomic Profiling Provide Novel Insights into Fruit Ripening and Ripening Disorder Caused by 1-MCP Treatments in Papaya

Abstract

Treatment with 1-methylcyclopropylene (1-MCP) is an effective technique to preserve fruits, but inappropriate treatment with 1-MCP causes a ripening disorder (rubbery texture) in papaya fruit. In this study, a combined metabolomic and transcriptomic analysis was conducted to reveal the possible mechanism of the ripening disorder caused by unsuitable 1-MCP in papaya. A total of 203 differential accumulated metabolites (DAMs) were identified in the metabolome analysis. Only 24 DAMs were identified in the control (CK) vs. the 1-MCP 2 h group, and they were primarily flavonoids. Ninety and 89 DAMs were identified in the CK vs. 1-MCP 16 h and 1-MCP 2 h vs. 1-MCP 16 h groups, respectively, indicating that long-term 1-MCP treatment severely altered the metabolites during fruit ripening. 1-MCP 16 h treatment severely reduced the number of metabolites, which primarily consisted of flavonoids, lipids, phenolic acids, alkaloids, and organic acids. An integrated analysis of RNA-Seq and metabolomics showed that various energy metabolites for the tricarboxylic acid cycle were reduced by long-term treatment with 1-MCP, and the glycolic acid cycle was the most significantly affected, as well as the phenylpropane pathway. These results provide valuable information for fruit quality control and new insight into the ripening disorder caused by unsuitable treatment with 1-MCP in papaya.

Role of integrated omics in unravelling fruit stress and defence responses during postharvest: A review

“…Red Globe Grape) Y. lipolytica POs & TOs DEGs, GO, KEGG Y. lipolytica induce expression of gene involved in protection of host from pathogens, upregulated for gene encoding synthesis of phytoalexin, pathogenesis-related protein WRKY transcription factor, hypertensive protein compared to controls Zhao et al, 2021 Papaya (cv. Suiyou-2) 1-MCP TOs & MOs PCA, and hierarchical cluster (HCA), OPLS-DA, KEGG 1-MCP delayed ripening and quality deterioration 1-MCP long term treatment (2hr) resulted ripening disorder, DEGs and DEMs indicated inhibition of basal metabolism and secondary metabolites that count for ripening disorder Zheng et al, 2021 Navel orange (cv. Lane Late) Edible coating/ waxingstored at room temperature (22 ± 2 °C) and 55-60% RH POs & MOs Co-expression network – WGCNA, Hierarchical clustering analysis (HCA) 167 key hypoxia responsive proteins, involve in mitochondrial metabolism were identified using WGCNA HCA resulted differences in protein abundance and expression pattern between waxed and control fruit Low O 2 condition alter mitochondrial proteome resulted in mitochondrial metabolism (organic and amino acid) and accumulation of metabolites (succinic acid and GABA) Li et al, 2022 Green bell pepper (cv.…”

Genomic Approaches for Improvement of Tropical Fruits: Fruit Quality, Shelf Life and Nutrient Content

“…Furthermore, non-coding miRNAs such as cpa-miR390a targeting ethylene and cpa-miR396 targeting auxin signalling pathways were found to be regulating the ripening process in 1-MCP treated fruits [ 102 ]. A comparative metabolome and transcriptome analysis further revealed that prolonged 1-MCP treatment drastically altered metabolites such as flavonoids, lipids, phenolic acids, alkaloids and organic acids in papaya fruits [ 9 ]. Metabolome cum proteome profiling of ethylene treated papaya fruits for 6 h was shown to have increased levels of GABA and volatile compounds such as terpene linalool and hastened the ripening process [ 174 ].…”

“…Difficulties in conventional breeding can be minimized by employing molecular breeding techniques, supported by information on molecular markers, genetic linkage maps, whole genome sequence, genotyping by sequencing (GBS), transcriptome, metabolome and proteome profiles. This facilitates understanding of the functional roles of genes, transcription factors and pathways involved in fruit characters, ripening mechanism and resistance to disease and adverse environmental conditions [ 8 , 9 ]. Adapting an integrated ‘multi-omics’ approach aids in increasing the genomic knowledge and its applicability in developing improved cultivars ( Figure 1 ).…”

A Review of Omics Technologies and Bioinformatics to Accelerate Improvement of Papaya Traits

“…However, little is known on the integration between metabolomics and transcriptomics to understand the mechanism during the fruit-ripening process. It has been reported that metabolites (i.e., flavonoids, terpenoids, organic acids, phenolic acids, and alkaloids) are closely related to the ripening disorder of fruits [101][102][103]. The elucidation of these potential metabolites during papaya-ripening processes will provide valuable information for developing a strategy for postharvest storage and improving the fruit quality.…”