AUTHOR=Zhang Shaoyu , Ding Guangyu , He Wenmin , Liu Kai , Luo Yiwei , Tang Jiaqi , He Ningjia 

TITLE=Functional Characterization of the 1-Deoxy-D-Xylulose 5-Phosphate Synthase Genes in Morus notabilis

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.01142

DOI=10.3389/fpls.2020.01142

ISSN=1664-462X

ABSTRACT=<p>Terpenoids are considered to be the largest group of secondary metabolites and natural products. Studies have revealed 1-deoxy-D-xylulose 5-phosphate synthase (DXS) is the first and rate-limiting enzyme in the plastidial methylerythritol phosphate pathway, which produces isopentenyl diphosphate and its isoform dimethylallyl diphosphate as terpenoid biosynthesis precursors. Mulberry (<italic>Morus</italic> L.) is an economically and ecologically important perennial tree with diverse secondary metabolites, including terpenoids that protect plants against bacteria and insects and may be useful for treating human diseases. However, there has been relatively little research regarding <italic>DXS</italic> genes in mulberry and other woody plant species. In this study, we cloned and functionally characterized three <italic>Morus notabilis DXS</italic> genes (<italic>MnDXS1</italic>, <italic>MnDXS2A</italic>, and <italic>MnDXS2B</italic>). Bioinformatics analyses indicated <italic>MnDXS1</italic> belongs to clade 1, whereas <italic>MnDXS2A</italic> and <italic>MnDXS2B</italic> are in clade 2. The three encoded MnDXS proteins are localized to chloroplasts. Additionally, substantial differences in <italic>MnDXS</italic> expression patterns were observed in diverse tissues and in response to insect feeding and methyl jasmonate treatment. Moreover, overexpression of <italic>MnDXS1</italic> in <italic>Arabidopsis thaliana</italic> increased the gibberellic acid content and resulted in early flowering, whereas overexpression of <italic>MnDXS2A</italic> enhanced root growth and increased the chlorophyll and carotenoid content. Our findings indicate that <italic>MnDXS</italic> functions vary among the clades, which may be useful for further elucidation of the functions of the <italic>DXS</italic> genes in mulberry.</p>