GbFLSa overexpression negatively regulates proanthocyanin biosynthesis

Jing Guo; Yaqiong Wu; Tongli Wang; Yue Xin; Guibin Wang; Qi Zhou; Li-An Xu

doi:10.3389/fpls.2023.1093656

GbFLSa overexpression negatively regulates proanthocyanin biosynthesis

Front Plant Sci. 2023 Feb 15:14:1093656. doi: 10.3389/fpls.2023.1093656. eCollection 2023.

Authors

Jing Guo¹, Yaqiong Wu^{1

2

3}, Tongli Wang³, Yue Xin¹, Guibin Wang¹, Qi Zhou^{1

4}, Li-An Xu¹

Affiliations

¹ Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China.
² Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, China.
³ Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Vancouver, BC, Canada.
⁴ Forest Breeding Institute, Zhejiang Academy of Forestry, Hangzhou, China.

Abstract

Flavonoids are important secondary metabolites with extensive pharmacological functions. Ginkgo biloba L. (ginkgo) has attracted extensive attention because of its high flavonoid medicinal value. However, little is understood about ginkgo flavonol biosynthesis. Herein, we cloned the full-length gingko GbFLSa gene (1314 bp), which encodes a 363 amino acid protein that has a typical 2-oxoglutarate (2OG)-Fe(II) oxygenase region. Recombinant GbFLSa protein with a molecular mass of 41 kDa was expressed in Escherichia coli BL21(DE3). The protein was localized to the cytoplasm. Moreover, proanthocyanins, including catechin, epicatechin, epigallocatechin and gallocatechin, were significantly less abundant in transgenic poplar than in nontransgenic (CK) plants. In addition, dihydroflavonol 4-reductase, anthocyanidin synthase and leucoanthocyanidin reductase expression levels were significantly lower than those of their CK counterparts. GbFLSa thus encodes a functional protein that might negatively regulate proanthocyanin biosynthesis. This study helps elucidate the role of GbFLSa in plant metabolism and the potential molecular mechanism of flavonoid biosynthesis.

Keywords: flavonoid biosynthesis; flavonol synthase; gene expression; metabolite; transgenic poplar.

Grants and funding

This study was supported by the National Natural Science Foundation of China (31971689), the National Natural Science Foundation of China (31902064), the Special Fund for Forest Scientific Research in the Public Welfare (201504105), the National Key Research and Development Program of China (2017YFD0600700), the Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX18_0954), and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).