Transcriptomic Analysis of Root Restriction Effects on the Primary Metabolites during Grape Berry Development and Ripening

Feng Leng,Xian Li,Jinping Cao,Ling Jiang,Naymul Karim,Yue Wang,Jinsong Bao,Chongde Sun,Di Wu,Shiping Wang

doi:10.3390/genes13020281

Abstract

Root restriction (RR) has been reported to enhance grape berry quality in diverse aspects of grape life. In this study, RR-induced increases in the main primary metabolites in the grape berry and the expression of their related genes were studied at different developmental stages. Mainly the transcriptomic and metabolomic level were analyzed using ‘Summer Black’ grape berry as a material. The main results were as follows: A total of 11 transcripts involved in the primary metabolic pathways were significantly changed by the RR treatment. Metabolites such as sugars, organic acids, amino acids, starch, pectin, and cellulose were qualitatively and quantitatively analyzed along with their metabolic pathways. Sucrose synthase (VIT_07s0005g00750, VIT_11s0016g00470) and sucrose phosphate synthase (VIT_18s0089g00410) were inferred to play critical roles in the accumulation of starch, sucrose, glucose, and fructose, which was induced by the RR treatment. RR treatment also promoted the malic acid and tartaric acid accumulation in the young berry. In addition, the grape berries after the RR treatment tended to have lower pectin and cellulose content.

Highlights

Grape growth is characterized during the initial phase, when the berries are small, hard, and acidic
From the RNA-Seq results, significant changes were found in the expressions of 11 genes that were involved in sucrose synthesis and degradation, glycolysis, and the tricarboxylic acid cycle (TCA) metabolic pathways of the two treatments during different developmental stages in the primary metabolic pathways (Table 2)
The combined analysis of genes and compounds contributed to exploring the general effects of the RR treatment on the primary metabolisms during the whole fruit growth process

Summary

Introduction

Grape growth is characterized during the initial phase, when the berries are small, hard, and acidic. It becomes larger, softer, and sweeter due to the accumulation of a series of organoleptic compounds. Grape berries undergo a series of complex biochemical and physiological changes during growth, which can be divided into three distinct phases [1,2]. The berry size increases sigmoidally due to the cell division and expansion. Organic acids (mainly tartaric and malic acids) are synthesized in the vacuoles and reach maximal concentrations at the end of this phase. A large number of flavor metabolites and aromas are synthesized at the end of this phase [2,3]

Methods

Results

Discussion

Conclusion