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

Abstract

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 ( Morus 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 DXS genes in mulberry and other woody plant species. In this study, we cloned and functionally characterized three Morus notabilis DXS genes ( MnDXS1 , MnDXS2A , and MnDXS2B ). Bioinformatics analyses indicated MnDXS1 belongs to clade 1, whereas MnDXS2A and MnDXS2B are in clade 2. The three encoded MnDXS proteins are localized to chloroplasts. Additionally, substantial differences in MnDXS expression patterns were observed in diverse tissues and in response to insect feeding and methyl jasmonate treatment. Moreover, overexpression of MnDXS1 in Arabidopsis thaliana increased the gibberellic acid content and resulted in early flowering, whereas overexpression of MnDXS2A enhanced root growth and increased the chlorophyll and carotenoid content. Our findings indicate that MnDXS functions vary among the clades, which may be useful for further elucidation of the functions of the DXS genes in mulberry.

Identification and Functional Analysis of 1-Deoxy-D-xylulose-5-phosphate Synthase Gene in Tomatoes (Solanum lycopersicum)

“…An analysis of the subcellular localization of the proteins showed that SlDXS proteins are all predicted to be localized in the chloroplasts. This is consistent with the fact that the three DXS genes of Morus notabilis are located in chloroplasts [36]. The MEP pathway occurs in plastids, so it is reasonable that the SlDXS genes are located in chloroplasts [36].…”

“…This is consistent with the fact that the three DXS genes of Morus notabilis are located in chloroplasts [36]. The MEP pathway occurs in plastids, so it is reasonable that the SlDXS genes are located in chloroplasts [36]. It was found that the DXS gene family contains three subfamilies, namely DXS I, DXS II, and DXS III, each with different functions [33].…”

“…Applying exogenous MeJA treatment to Goosegrass rhizomes leads to an increase in the triterpenoid saponin content [51]. It was found that the expression of MnDXS2A and MnDXS2B is up-regulated by the exogenous MeJA treatment of mulberry seedling leaves, which was hypothesized to be possibly related to certain metabolites in the plant and plant defense system [36]. In this study, where MeJA was used to treat tomato leaves, SlDXS1 and SlDXS3 were not responsive to MeJA, whereas the expression of SlDXS2 was up-regulated to the maximum at 3 h, indicating that SlDXS2 can be significantly induced by exogenous MeJA.…”

Unravelling the genetic framework associated with grain quality and yield-related traits in maize (Zea mays L.)

“…Several genes identified within the validated hotspot regions encode enzymes involved in various metabolic processes, such as terpenoid biosynthesis (1-deoxy-D-xylulose-5-phosphate reductoisomerase) ( Zhang et al, 2020 ), auxin dependent endomembrane homeostasis (1-phosphatidylinositol-3-phosphate 5-kinase ( Lo et al, 2022 ), oil biosynthesis (acyltransferase) ( Yan et al, 2018 ), photorespiration (alanine--glyoxylate transaminase which is known to facilitate the transamination between L-alanine and glyoxylate to produce pyruvate and glycine) ( Liepman et al, 2019 ), lipid metabolism (aspartic proteinase oryzasin-1) ( Alexandrov et al, 2009 ), carbohydrate metabolism (endoglucanase) ( Jiao et al, 2017 ), sugar isomerization (epimerase domain-containing protein), phosphorus remobilization (glycerophosphodiester phosphodiesterase) ( Wang J. et al, 2021 ), etc.…”

Comparative transcriptome profiling and weighted gene co-expression network analysis to identify core genes in maize (Zea mays L.) silks infected by multiple fungi

“…A similar result was reported by Cordoba et al (2011) who demonstrated plastid localization in Z. mays leaves. DXS catalyzes the first reaction that converts pyruvate and glyceraldehyde-3-phosphate to 1-deoxy-D-xylulose 5-phosphate in the methylerythritol phosphate pathway (Tambasco-Studart et al, 2005;Zhang et al, 2020). The remaining cluster 5 and nodes, namely, 7, 10, 11, and12 (Table 2), do not cover up the pathways under the high scoring method within the top 100 (Supplementary Table S15).…”