Transcriptomic analysis reveals hub genes and subnetworks related to ROS metabolism in Hylocereus undatus through novel superoxide scavenger trypsin treatment during storage

Xin Li,Yong Yin,Yunxia Yuan,Huichun Yu,Xinyue Pang,Xueru Liu,Bairu Li

doi:10.1186/s12864-020-06850-1

Abstract

BackgroundIt was demonstrated in our previous research that trypsin scavenges superoxide anions. In this study, the mechanisms of storage quality improvement by trypsin were evaluated in H. undatus.ResultsTrypsin significantly delayed the weight loss and decreased the levels of ROS and membrane lipid peroxidation. Transcriptome profiles of H. undatus treated with trypsin revealed the pathways and regulatory mechanisms of ROS genes that were up- or downregulated following trypsin treatment by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses. The current results showed that through the regulation of the expression of hub redox enzymes, especially thioredoxin-related proteins, trypsin can maintain low levels of endogenous active oxygen species, reduce malondialdehyde content and delay fruit aging. In addition, the results of protein-protein interaction networks suggested that the downregulated NAD(P) H and lignin pathways might be the key regulatory mechanisms governed by trypsin.ConclusionsTrypsin significantly prolonged the storage life of H. undatus through regulatory on the endogenous ROS metabolism. As a new biopreservative, trypsin is highly efficient, safe and economical. Therefore, trypsin possesses technical feasibility for the quality control of fruit storage.Graphical abstract

Highlights

It was demonstrated in our previous research that trypsin scavenges superoxide anions
Effect on storage quality of H. undatus The H. undatus fruits of both groups were in excellent condition at the beginning of storage (Fig. 1)
From the information of the arrow directions, either NDA1 (Internal NAD(P) H dehydrogenase in mitochondria) or AOR (NADPH-dependent alkenal/one oxidoreductase, chloroplastic) is the upstream gene of AT5G06060 (Fig. 6). This pathway is dependent on the redox of NAD(P) H, which is the main source of O2−. These results strongly indicated that the downregulated NAD(P) H and lignin pathways might be the key regulatory mechanisms of trypsin, the superoxide scavenger, on the quality improvement of H. undatus during storage

Summary

Introduction

It was demonstrated in our previous research that trypsin scavenges superoxide anions. The mechanisms of storage quality improvement by trypsin were evaluated in H. undatus. H. undatus is a nonclimacteric fruit that reaches its best edible quality when harvested ripe, and its quality decreases during storage. As a newly cultivated crop, few studies have aimed to extend the postharvest quality of this fruit [2]. It was shown that the presence of trypsin significantly affects the activity of flavonoids in scavenging 2,2-diphenyl-1- picrylhydrazyl (DPPH), 2, 2-azinobis (3ethylbenzo- thiazoline-6-sulphonic acid; ABTS) and hydroxyl radicals [5]. We reported that trypsin can protect cells by scavenging superoxide anions (O2−) [6]. The function and mechanisms of the impact of trypsin on the quality of H. undatus during storage have not been determined to date

Methods

Results

Discussion

Conclusion