Effect of Thidiazuron on Terpene Volatile Constituents and Terpenoid Biosynthesis Pathway Gene Expression of Shine Muscat (Vitis labrusca × V. vinifera) Grape Berries.

Wu Wang,Niels J Nieuwenhuizen,Jian-Min Tao,Huan Zheng,Muhammad Khalil-Ur-Rehman,Ling-Ling Wei

doi:10.3390/molecules25112578

Wu Wang, Niels J Nieuwenhuizen + Show 4 more

Open Access

https://doi.org/10.3390/molecules25112578

Copy DOI

Abstract

Volatile compounds are considered to be essential for the flavor and aroma quality of grapes. Thidiazuron (TDZ) is a commonly used growth regulator in grape cultivation that stimulates larger berries and prevents fruit drop. This study was conducted to investigate the effect of TDZ on the production of aroma volatiles and to identify the key genes involved in the terpene biosynthesis pathways that are affected by this compound. Treatment with TDZ had a negative effect on the concentration of volatile compounds, especially on monoterpenes, which likely impacts the sensory characteristics of the fruit. The expression analysis of genes related to the monoterpenoid biosynthesis pathways confirmed that treatment with TDZ negatively regulated the key genes DXS1, DXS3, DXR, HDR, VvPNGer and VvPNlinNer1. Specifically, the expression levels of the aforementioned genes were down-regulated in almost all berry development stages in the TDZ-treated samples. The novel results from the present study can be used to aid in the development of food products which maintain the flavor quality and sensory characteristics of grape. Furthermore, these findings can provide the theoretical basis that can help to optimize the utilization of TDZ for the field production of grapes at a commercial scale.

Highlights

Grape (Vitis vinifera L.) is a high value fruit crop worldwide which is consumed fresh as berries or utilized to produce wine
Aroma compounds can exist as free volatiles and a subset can occur as glycoside conjugates [2], which collectively contribute to the sensory characteristics of grapes
Results demonstrate that exogenous application of TDZ decreases the Terpene Synthase (TPS) enzyme activity and negatively regulates the expression of several genes involved in the terpene metabolic pathway towards the biosynthesis of monoterpenes

Summary

Introduction

Grape (Vitis vinifera L.) is a high value fruit crop worldwide which is consumed fresh as berries or utilized to produce wine. Shine Muscat, a table grape cultivar which originated from Japan, is currently very popular in Asia—especially in China and Japan, due to its high brix level, large berry size and pleasant Muscat flavor [1]. The taste and aroma of grape are affected by many components such as soluble sugars, organic acids and volatile compounds. Aroma is the key factor affecting the flavor of grapes. The volatile composition of Shine Muscat grape has been extensively documented and found to be primarily derived from C6 compounds, alcohols, esters, aldehydes and terpenes [3,4]

Methods

Results

Conclusion