Comparative metabolomics reveals differences in primary and secondary metabolites between "Shixia" and "Chuliang" longan (Dimocarpus longan Lour.) pulp

Tingting Lai; Liang Shuai; Dongmei Han; Ziying Lai; Xinxin Du; Xiaomeng Guo; Wenshun Hu; Zhenxian Wu; Tao Luo

doi:10.1002/fsn3.2552

Comparative metabolomics reveals differences in primary and secondary metabolites between "Shixia" and "Chuliang" longan (Dimocarpus longan Lour.) pulp

Food Sci Nutr. 2021 Aug 28;9(10):5785-5799. doi: 10.1002/fsn3.2552. eCollection 2021 Oct.

Authors

Tingting Lai¹, Liang Shuai², Dongmei Han³, Ziying Lai¹, Xinxin Du¹, Xiaomeng Guo¹, Wenshun Hu⁴, Zhenxian Wu^{1

5}, Tao Luo¹

Affiliations

¹ College of Horticulture South China Agricultural University/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Engineering Research Center of Southern Horticultural Products Preservation Ministry of Education Guangzhou China.
² College of Food and Biological Engineering/Institute of Food Science and Engineering Technology Hezhou University Hezhou China.
³ Institute of Fruit Tree Research Guangdong Academy of Agricultural Sciences/Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization Ministry of Agriculture Guangzhou China.
⁴ Fruit Research Institute Fujian Academy of Agricultural Sciences Fuzhou China.
⁵ Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China) Ministry of Agriculture and Rural Affairs/Guangdong Litchi Engineering Research Center Guangzhou China.

Abstract

Longan was a characteristic fruit for both medicine and food in China, which was rich in primary and secondary metabolites. Comprehensive high-throughput identification and comparison of metabolites in longan pulp among different varieties were still lacked. "Shixia" (SX) and "Chuliang" (CL) were the biggest major cultivars of longan in China. In this study, the content of total soluble solid, total flavonoid, and total phenolics indicated the difference of sweetness and bioactive compound content between the SX and CL pulp. Through a widely targeted metabolome, a total of 514 metabolites were identified and categorized into 23 groups mainly including flavonoids, amino acids & derivatives, lipids, phenolic acids, nucleotides & derivatives, alkaloids, organic acids and sugars & derivatives. A total of 89 metabolites with significantly differential accumulation (variable importance in projection (VIP) value ≧1, p-value <.05) over 1.2 fold were found between SX and CL, which were mainly enriched into pathways including flavone and flavonol biosynthesis, glycolysis/gluconeogenesis, and arginine and proline metabolism. Higher leveled hexose and hexose-phosphate (i.e., β-D-glucose, D(+)-glucose, glucose-1-phosphate and glucose-6-phosphate), dominant organic acids (i.e., citric acid, succinic acid, D-malic acid, and citramalate), and essential amino acids (L-threonine, L-valine, L-isoleucine, L-leucine, L-phenylalanine and L-lysine) in SX pulp might be contributed to the taste and flavor difference between SX and CL. Moreover, the greatly differential accumulated secondary metabolites especially flavonoids and phenolic acids might result in different medicinal and nutritional characteristic between SX and CL. In conclusion, this study provided a systemic metabolic basis for understanding the nutritional differences between SX and CL and would help deepen the molecular biology and pharmacology research on characteristic metabolites in longan pulp.

Keywords: differentially accumulated metabolites; longan (Dimocarpus longan Lour.) pulp; variable importance in projection (VIP) value; widely targeted metabolome; “Chuliang” longan; “Shixia” longan.