UPLC-Q-TOF/MS-based metabolomic analysis reveals the effects of asomate on the citrus fruit

Guangyun He; Xi Chen; Xue Hou; Xi Yu; Mei Han; Shiting Qiu; Ying Li; Shudi Qin; Fengyi Wang

doi:10.1016/j.crfs.2023.100523

UPLC-Q-TOF/MS-based metabolomic analysis reveals the effects of asomate on the citrus fruit

Curr Res Food Sci. 2023 May 20:6:100523. doi: 10.1016/j.crfs.2023.100523. eCollection 2023.

Authors

Guangyun He^{1

2}, Xi Chen³, Xue Hou^{1

2}, Xi Yu⁴, Mei Han^{1

2}, Shiting Qiu^{1

2}, Ying Li^{1

2}, Shudi Qin^{1

2}, Fengyi Wang^{1

2}

Affiliations

¹ Institute of Quality Standard and Testing Technology for Agro-Products, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, China.
² Laboratory of Quality and Safety Risk Assessment for Agro-products (Chengdu), Ministry of Agriculture, Chengdu, 610066, China.
³ SCIEX Analytical Instrument Trading Co., Shanghai, 200335, China.
⁴ Faculty of Medicine, Macau University of Science and Technology, Macau, 999078, China.

Abstract

The regulation of the sugar-acid ratio is of great significance to the improvement of citrus fruit quality. The citric acid level in fruit is influenced by many factors. Among them, cultivar selection and production practices are the most important strategies under the grower's control. In recent years, an arsenic-containing preparation called "Tianmisu", with the main ingredient of asomate, has occasionally been reported to be used in citrus cultivation to improve the sweetness of fruits. In order to reveal the effects of the pesticide on citrus fruits, 'Harumi' tangor was treated with "Tianmisu", and the impact of this pesticide on fruit quality and metabolites was investigated through UPLC-Q-TOF/MS-based metabolomic analysis. Compared with the control, the concentration of titratable acidity, in particular citric acid, in the pulp of 'Harumi' tangor treated with the pesticide, was significantly reduced by 60.5%. The differences in metabolites between the pesticide-treated samples and the control were illustrated by Principal Component Analysis (PCA) and Partial Least Squares Discriminant Analysis (PLS-DA). The PLS-DA analysis demonstrated a clear discrimination, with R²Y and Q² values of 0.982 and 0.933 in the positive mode and 0.984 and 0.900 in the negative mode, respectively. A total of 155 compounds were identified, and 63 characteristic components were screened out from the pesticide-treated samples compared to the control. Aside from the upregulation observed for a few metabolites, the majority of the compounds, including citric acid and various lipids, were down-regulated in the treated citrus fruits compared to the control. This study can serve as a basis for understanding the regulatory mechanism of organic acids in citrus and will be helpful in developing different strategies to improve citrus quality.

Keywords: Asomate; Chemometrics; Citric acid; Citrus fruits; Metabolomics; UPLC-Q-TOF/MS.