Functional and evolutionary analysis of DXL1, a non-essential gene encoding a 1-deoxy-D-xylulose 5-phosphate synthase like protein in Arabidopsis thaliana

Abstract

Q2Despite their diversity in structures and functions, all 60 isoprenoids are derived from the common precursor isopentenyl di-61 phosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP). 62Until recently, it was assumed that IPP and DMAPP were solely syn-63 thesized through the mevalonic acid (MVA) pathway (Chappell, 64 1995). However, it is now well established that they can also be pro-65 duced by the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway 66 (Lichtenthaler, 1999;Rodriguez-Concepcion and Boronat, 2002 81Another mechanism known to provide plasticity to plant metabolic 82 responses is provided by functional diversification of specific enzymes. 83Enzymes involved in secondary metabolic pathways are commonly

Terpene synthases from Cannabis sativa

“…Terpenes in the roots, if present in cannabis, may contribute to defense as reported in other plant species [10]. In plants, DXS genes generally fall into two clades, of which DXS I members are generally involved in primary metabolism, and DXS II members are often induced in defense responses [40, 41, 42]. Abundance of cannabis DXS2 transcripts, which clusters with the DXS II subfamily (S1 Fig), suggests defense related terpenoids in cannabis roots and warrants future work on the cannabis root metabolome.…”

The 2-C-methylerythritol 4-phosphate pathway in melon is regulated by specialized isoforms for the first and last steps

“…The failure to detect authentic DXS activity in CmDXL by two independent methods, coupled to its highly upregulated transcripts in developing fruit and de-etiolating seedlings, suggests it encodes a protein with an activity different from that of DXS. Arabidopsis AtDXL1 (a type I DXS) was found to be a non-essential gene which similarly lacks DXS activity (Carretero-Paulet et al , 2013). Unlike its functional paralogue CLA1/DXS1, it is not expressed in leaves or induced by light and is mainly expressed in siliques and flowers.…”

“…Unlike its functional paralogue CLA1/DXS1, it is not expressed in leaves or induced by light and is mainly expressed in siliques and flowers. An evolutionary analysis of this plastid-localized protein suggested it had evolved recently through gene duplication of CLA1/DXS1 in the Brassicaceae line (Carretero-Paulet et al , 2013). The additional observation that CmDXL suppresses endogenous DXS activity in in vitro assays of crude protein preparations (compared to non-transformed controls) suggests it may share a common substrate with DXS.…”

Albino T-DNA tomato mutant reveals a key function of 1-deoxy-D-xylulose-5-phosphate synthase (DXS1) in plant development and survival

“…Arabidopsis DXS1 and DXS2 genes show high homology and are both included in the subfamily DXS134, suggesting that they would have redundant functions. However, the Arabidopsis DXS2 gene has recently been renamed as DXL1 , which might not have DXS activity, but rather has acquired a novel, as yet unknown biochemical function32. In contrast, the Arabidopsis DXS3 gene has been grouped within a clade composed of highly divergent protein sequences20, which lack many of the highly conserved residues known to be essential for DXS activity44.…”

“…Additionally, characterization of DXS mutants has shed light on the key function of DXS proteins in plant development2630. In Arabidopsis, DXS1 plays an essential role in chloroplast development during leaf cell maturation3031, while DXS2 seems to have no DXS activity, but it has acquired another unknown biochemical function32. In tomato, the DXS1 function is required for carotenoid biosynthesis during fruit ripening19, while tomato DXS2 participates in the biosynthesis of isoprenoids in trichomes162233 and of secondary metabolites16.…”