AUTHOR=Guo Jing , Wu Yaqiong , Wang Tongli , Xin Yue , Wang Guibin , Zhou Qi , Xu Li-An 

TITLE=GbFLSa overexpression negatively regulates proanthocyanin biosynthesis

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1093656

DOI=10.3389/fpls.2023.1093656

ISSN=1664-462X

ABSTRACT=<p>Flavonoids are important secondary metabolites with extensive pharmacological functions. <italic>Ginkgo biloba</italic> 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 <italic>GbFLSa</italic> 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 <italic>Escherichia coli</italic> 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, <italic>dihydroflavonol 4-reductase</italic>, <italic>anthocyanidin synthase</italic> and <italic>leucoanthocyanidin reductase</italic> 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.</p>