Combined Metabolome and Transcriptome Profiling Reveal Optimal Harvest Strategy Model Based on Different Production Purposes in Olive

Guodong Rao,Jianguo Zhang,Chenhe Wang,Xiaoxia Liu,Xue Li

doi:10.3390/foods10020360

Abstract

Olive oil has been favored as high-quality edible oil because it contains balanced fatty acids (FAs) and high levels of minor components. The contents of FAs and minor components are variable in olive fruits of different color at harvest time, which render it difficult to determine the optimal harvest strategy for olive oil producing. Here, we combined metabolome, Pacbio Iso-seq, and Illumina RNA-seq transcriptome to investigate the association between metabolites and gene expression of olive fruits at harvest time. A total of 34 FAs, 12 minor components, and 181 other metabolites (including organic acids, polyols, amino acids, and sugars) were identified in this study. Moreover, we proposed optimal olive harvesting strategy models based on different production purposes. In addition, we used the combined Pacbio Iso-seq and Illumina RNA-seq gene expression data to identify genes related to the biosynthetic pathways of hydroxytyrosol and oleuropein. These data lay the foundation for future investigations of olive fruit metabolism and gene expression patterns, and provide a method to obtain olive harvesting strategies for different production purposes.

Highlights

Olive oil originated in the Mediterranean and is a widely recognized, high-quality, edible vegetable oil [1]
The abundances of the three fatty acids (FAs) increased with increasing maturity stages (Table 1)
The metabolomics data in this study indicated that the content of eight main fatty acids increased as the color became darker in olive fruits (Figure 1A), and the purple fruits have the highest total contents of FAs (Figure 1B), suggesting that if producers want to increase the output of fatty acids, they should add more purple fruits, which is consistent with the traditional harvesting method based on experience

Summary

Introduction

Olive oil originated in the Mediterranean and is a widely recognized, high-quality, edible vegetable oil [1]. The consumption of olive oil has gradually increased over the past. 10 years, even in some non-oil olive producing areas like Japan and Canada [2]. This increase in popularity is due in large part to its nutritional and health-promoting effects. Olive oil contains a high abundance of mono- and poly-unsaturated fatty acids that are more absorbed by humans [1,3]. Olive oil contains many minor components that are beneficial to human health, including chlorophyll, polyphenols, and tocopherols. Hydroxytyrosol, oleuropein, and squalene are substances in olive oil, which are otherwise very rare in plant oils and have great human health benefits owing to antioxidative capacity [4,5,6]

Methods

Results

Discussion

Conclusion