Assessing Dynamic Changes of Taste-Related Primary Metabolism During Ripening of Durian Pulp Using Metabolomic and Transcriptomic Analyses

Lalida Sangpong,Kazuki Saito,Joachim Kopka,Alexander Erban,Gholamreza Khaksar,Akira Oikawa,Mutsumi Watanabe,Takayuki Tohge,Karan Wangpaiboon,Pinnapat Pinsorn,Ryosuke Sasaki,Rainer Hoefgen,Supaart Sirikantaramas

doi:10.3389/fpls.2021.687799

Abstract

Durian is an economically important fruit of Southeast Asia. There is, however, a lack of in-depth information on the alteration of its metabolic networks during ripening. Here, we annotated 94 ripening-associated metabolites from the pulp of durian cv. Monthong fruit at unripe and ripe stages, using capillary electrophoresis- and gas chromatography- time-of-flight mass spectrometry, specifically focusing on taste-related metabolites. During ripening, sucrose content increased. Change in raffinose-family oligosaccharides are reported herein for the first time. The malate and succinate contents increased, while those of citrate, an abundant organic acid, were unchanged. Notably, most amino acids increased, including isoleucine, leucine, and valine, whereas aspartate decreased, and glutamate was unchanged. Furthermore, transcriptomic analysis was performed to analyze the dynamic changes in sugar metabolism, glycolysis, TCA cycle, and amino acid pathways to identify key candidate genes. Taken together, our results elucidate the fundamental taste-related metabolism of durian, which can be exploited to develop durian metabolic and genetic markers in the future.

Highlights

Durian (Durio zibethinus L.) is a highly economically valuable fruit endemic to Southeast Asia, which has recently begun to be distributed globally
Titratable acidity refers to total acid contents inside the food
gas chromatography (GC)-time-of-flight mass spectrometry (TOF/MS) results indicated that nine pathways were significantly impacted (Figure 1D), including starch and sugar metabolism, as well as some amino acid pathways that were previously found in the capillary electrophoresis (CE)-TOF/MS analysis (Supplementary Table 3)

Summary

INTRODUCTION

Durian (Durio zibethinus L.) is a highly economically valuable fruit endemic to Southeast Asia, which has recently begun to be distributed globally. Metabolomics, coupled with transcriptomics, provides information on major metabolic networks and candidate genes controlling the underlying processes; integration of these data with genomics provides new insights into the major metabolic variations and their genetic and biochemical control during development Such studies have widely been performed on tomato, a popular model fruit, and documented how breeding and genetic selection globally altered tomato fruit metabolite content (Zhu et al, 2018). A member of the auxin response factor (ARF) transcription factor family was identified, showing that DzARF2A mediates durian fruit ripening through transcriptional regulation of ethylene biosynthesis genes (Khaksar and Sirikantaramas, 2020) In this regard, omics analyses can be powerful tools to improve our limited understanding of the mechanisms underlying the durian postharvest ripening process, especially the changes in primary metabolites. The identification of ripening-associated metabolites, which contribute to its unique flavors, and key candidate genes may be further exploited in durian breeding programs to develop cultivars with altered sensory characteristics or enhanced nutritional value

MATERIALS AND METHODS

RESULTS AND DISCUSSION

DATA AVAILABILITY STATEMENT