AUTHOR=Zhang Dongrui , Tang Xun , Chen Lingling , Qiu Xiaojie , Song Chunhua , Wang Hemeng , Chang Ying 

TITLE=Functional characterization and transcriptional activity analysis of Dryopteris fragrans farnesyl diphosphate synthase genes

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1105240

DOI=10.3389/fpls.2023.1105240

ISSN=1664-462X

ABSTRACT=<p>Farnesyl diphosphate synthase (FPS), a key enzyme of the terpene metabolic pathway, catalyzes the precursor of sesquiterpene compounds farnesyl diphosphate (FPP) synthesis, and plays an important role in regulating plant growth and development. <italic>Dryopteris fragrans</italic> is a medicinal plant rich terpenoids. In this study, the function of the gene was verified <italic>in vitro</italic> and <italic>in vivo</italic>, the promoter of the gene was amplified and its transcriptional activity was analyzed. In the present study, we report the molecular cloning and functional characterization of <italic>DfFPS1</italic> and <italic>DfFPS2</italic>, two <italic>FPS</italic> genes from <italic>D. fragrans</italic>. We found that the two genes were evolutionarily conserved. Both <italic>DfFPS</italic> genes were highly expressed in the gametophyte and mature sporophyte leaves, and their expression levels increased in response to methyl jasmonate (MeJA) and high temperature. Both DfFPS proteins were localized in the cytoplasm and could catalyze FPP synthesis <italic>in vitro</italic>. We also found that the overexpression of <italic>DfFPS</italic> genes in tobacco plants promoted secondary metabolite accumulation but exhibited negligible effect on plant growth and development. However, the transgenic plants exhibited tolerance to high temperature and drought. The promoters of the two genes were amplified using fusion primer and nested integrated polymerase chain reaction (FPNI-PCR). The promoter sequences were truncated and their activity was examined using the β-glucuronidase (<italic>GUS</italic>) gene reporter system in tobacco leaves, and we found that both genes were expressed in the stomata. The transcriptional activity of the promoters was found to be similar to the expression pattern of the genes, and the transcriptional core regions of the two genes were mainly between −943 bp and −740 bp of <italic>proDfFPS1</italic>. Therefore, we present a preliminary study on the function and transcriptional activity of the <italic>FPS</italic> genes of <italic>D. fragrans</italic> and provide a basis for the regulation of terpene metabolism in <italic>D. fragrans</italic>. The results also provide a novel basis for the elucidation of terpene metabolic pathways in ferns.</p>