Characterization of Three Chalcone Synthase-like Genes in Dianthus Chinensis 

Abstract

Being an important garden plant, Dianthus chinensis flower has a great variety of colors and color patterns. Chalcone synthase (CHS) is the key enzyme in the anthocyanin biosynthetic pathway. Although CHS genes have been isolated and characterized in ornamental plants, the CHS gene is still unknown in D. chinensis. In our study, three CHS genes, DchCHS1 (KX893854), DchCHS2 (MK404175) and DchCHS3 (MK416198) were isolated in D. chinensis. Their deduced amino acid sequences show high homology with the known CHS sequences in Caryophyllaceae. The phylogenetic tree suggests that the DchCHS1 and the DchCHS3 have a close relation with the known CHS sequences in Caryophyllaceae and the DchCHS2 is different from them. The DchCHSs were characterized by the Tobacco Rattle Virus (TRV)-based virus-induced gene silencing (VIGS) system. We obtained white or pale purple flowers in the DchCHS1-silenced flowers and reducing purple flowers in the DchCHS2-silenced and the DchCHS3-silenced flowers. The anthocyanin content and the transcript level of the silenced DchCHS were significantly reduced in accordance with the silencing phenotypes. The DchCHSs showed different expression patterns during floral bud developments, among flower colors and in organs. Their expression levels in the purple flower were greatly higher than those in the white flower. Compared with DchCHS2 and DchCHS3, DchCHS1 was abundantly expressed at each floral bud stage, in each flower color and in the flower organ. In conclusion, the three DchCHSs are all involved in the anthocyanin synthesis and the flower coloration, and DchCHS1 probably plays a major role in D. chinensis flowers.

The isolation and expression analysis of cinnamate 4-hydroxylase and chalcone synthase genes of Scrophularia striata under different abiotic elicitors

“…Mahon et al (2021) in their study have reported that the induction of the chalcone synthetase 3 (CHS3) gene in transgenic poplar increased the accumulation of flavonoid naringenin in methanolic extracts of xylem compared to wild-type trees 26 . The CHS gene is widely isolated and characterized from many types of plants 27 – 31 . Besides genetic manipulations, the production of appropriate secondary metabolites requires the molecules triggering the production, because the biosynthetic pathway of the secondary metabolites is a part of the plant's defense mechanism against pathogens and herbivores.…”