Exogenously applied zinc improves sugar-acid profile of loquat (Eriobotrya japonica Lindl.) by regulating enzymatic activities and expression of their metabolism-related genes

Muhammad Moaaz Ali; Shaista Gull; Xiaobo Hu; Youming Hou; Faxing Chen

doi:10.1016/j.plaphy.2023.107829

Exogenously applied zinc improves sugar-acid profile of loquat (Eriobotrya japonica Lindl.) by regulating enzymatic activities and expression of their metabolism-related genes

Plant Physiol Biochem. 2023 Aug:201:107829. doi: 10.1016/j.plaphy.2023.107829. Epub 2023 Jun 8.

Authors

Muhammad Moaaz Ali¹, Shaista Gull², Xiaobo Hu¹, Youming Hou³, Faxing Chen⁴

Affiliations

¹ College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China; State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China; Institute of Subtropical Fruits, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
² Department of Horticulture, Bahauddin Zakariya University, Multan, 66000, Punjab, Pakistan.
³ State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China. Electronic address: ymhou@fafu.edu.cn.
⁴ College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China; State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China; Institute of Subtropical Fruits, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. Electronic address: cfaxing@126.com.

PMID: 37329690
DOI: 10.1016/j.plaphy.2023.107829

Abstract

Soluble sugars and organic acids are the most abundant components in ripe fruits, and they play critical roles in the development of fruit flavor and taste. In this study, loquat trees were sprayed with 0.1, 0.2 and 0.3% zinc sulphate. The contents of soluble sugars and organic acids were determined using HPLC-RID and UPLC-MS, respectively. The activities of key enzymes involved in sugar-acid metabolism were measured and expression profiling of related genes was done using RT-qPCR. The results revealed that 0.1% zinc sulphate was a promising treatment among other Zn applications with respect to the increased levels of soluble sugars and decreased acid contents in loquats. Correlation analysis showed that the enzymes i.e., SPS, SS, FK, and HK were may be involved in the regulation of fructose and glucose metabolism in the fruit pulp of loquat. While, the activity of NADP-ME showed negative and NAD-MDH showed a positive correlation with malic acid content. Meanwhile, EjSPS1-4, EjSS2-4, EjHK1-3, and EjFK1-6 may play an important role in soluble sugar metabolism in the pulp of loquat fruits. Similarly, EjPEPC2, EjPEPC3, EjNAD-MDH1, EjNAD-MDH3-5, EjNAD-MDH6 and EjNAD-MDH13 may have a vital contribution to malic acid biosynthesis in loquat fruits. This study provides new insights for future elucidation of key mechanisms regulating soluble sugars and malic acid biosynthesis in loquats.

Keywords: Fructokinase; Fructose; HPLC; Malate dehydrogenase; Malic acid; Zinc sulphate.