Transcriptome profiling of non-climacteric \u2018yellow\u2019 melon during ripening: insights on sugar metabolism

Michelle Orane Schemberger,Letícia Reis,Amanda Regina Godoy Baptistão,Rafael Mazer Etto,Ricardo Antonio Ayub,Michelle Zibetti Tadra Sfeir,Carolina Weigert Galvão,Kamila Karoline De Souza Los,Marília Aparecida Stroka,Gillize Aparecida Telles De Araujo

doi:10.1186/s12864-020-6667-0

Michelle Orane Schemberger, Letícia Reis + Show 8 more

Open Access

https://doi.org/10.1186/s12864-020-6667-0

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Abstract

BackgroundThe non-climacteric ‘Yellow’ melon (Cucumis melo, inodorus group) is an economically important crop and its quality is mainly determined by the sugar content. Thus, knowledge of sugar metabolism and its related pathways can contribute to the development of new field management and post-harvest practices, making it possible to deliver better quality fruits to consumers.ResultsThe RNA-seq associated with RT-qPCR analyses of four maturation stages were performed to identify important enzymes and pathways that are involved in the ripening profile of non-climacteric ‘Yellow’ melon fruit focusing on sugar metabolism. We identified 895 genes 10 days after pollination (DAP)-biased and 909 genes 40 DAP-biased. The KEGG pathway enrichment analysis of these differentially expressed (DE) genes revealed that ‘hormone signal transduction’, ‘carbon metabolism’, ‘sucrose metabolism’, ‘protein processing in endoplasmic reticulum’ and ‘spliceosome’ were the most differentially regulated processes occurring during melon development. In the sucrose metabolism, five DE genes are up-regulated and 12 are down-regulated during fruit ripening.ConclusionsThe results demonstrated important enzymes in the sugar pathway that are responsible for the sucrose content and maturation profile in non-climacteric ‘Yellow’ melon. New DE genes were first detected for melon in this study such as invertase inhibitor LIKE 3 (CmINH3), trehalose phosphate phosphatase (CmTPP1) and trehalose phosphate synthases (CmTPS5, CmTPS7, CmTPS9). Furthermore, the results of the protein-protein network interaction demonstrated general characteristics of the transcriptome of young and full-ripe melon and provide new perspectives for the understanding of ripening.

Highlights

The non-climacteric ‘Yellow’ melon (Cucumis melo, inodorus group) is an economically important crop and its quality is mainly determined by the sugar content
Colour measurement was expressed by the CIE (Commission Internationale de l’Eclairage) and Hue angle
The results showed that L* of peel increases up to 20 days after pollination (DAP), declines up to 30 DAP and remains stable until 40 DAP (Fig. 2b)

Summary

Introduction

The non-climacteric ‘Yellow’ melon (Cucumis melo, inodorus group) is an economically important crop and its quality is mainly determined by the sugar content. Melon (Cucumis melo L., Cucurbitaceae) is an economically important fruit crop worldwide that has an extensive polymorphism being classified into 19 botanical groups [1, 2] This high intra-specific genetic variation is reflected in fruit ripening differences. Glucose and fructose are the major soluble sugars, and sucrose is the predominant sugar in melons at maturity being stored in the vacuoles of the pericarp parenchyma cells [9, 12] Both climacteric and nonclimacteric melons accumulate sugar during fruit ripening [6]. The sugar content of C. melo species differs according to the genetic variety and development stage [9, 13]

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