cis‐prenyltransferase 3 and α/β‐hydrolase are new determinants of dolichol accumulation in Arabidopsis

Abstract

Dolichols (Dols), ubiquitous components of living organisms, are indispensable for cell survival. In plants, as well as other eukaryotes, Dols are crucial for post‐translational protein glycosylation, aberration of which leads to fatal metabolic disorders in humans and male sterility in plants. Until now, the mechanisms underlying Dol accumulation remain elusive. In this study, we have analysed the natural variation of the accumulation of Dols and six other isoprenoids among more than 120 Arabidopsis thaliana accessions. Subsequently, by combining QTL and GWAS approaches, we have identified several candidate genes involved in the accumulation of Dols, polyprenols, plastoquinone and phytosterols. The role of two genes implicated in the accumulation of major Dols in Arabidopsis—the AT2G17570 gene encoding a long searched for cis‐prenyltransferase (CPT3) and the AT1G52460 gene encoding an α/β‐hydrolase—is experimentally confirmed. These data will help to generate Dol‐enriched plants which might serve as a remedy for Dol‐deficiency in humans.

TheArabidopsis thalianaTRAPPIII subunit AtTRAPPC8/AtTRS85 is involved in ER functioning and autophagy

“…S7). The transcription of the MVA and MEP pathway genes: HMGR1 , HMGR2 , MVK , DXS , DXR , MCT , as well as of two FPP synthase genes: FPPS1 and FPPS2 , and of genes for the two final enzymes of Dol biosynthesis: CPT3 (Gawarecka et al, 2022) and PPRD2 (Jozwiak et al, 2015), remained at wild-type levels. Slight, but non-significant, induction was observed only for EVN which encodes a dolichol kinase (Lindner et al, 2015).…”

“…atg mutants display early leaf senescence in response to various nutrient-limiting conditions (reviewed by Chen et al, 2019). Increasing dolichol levels have long been considered a marker of aging in animal tissues (Chojnacki & Dallner, 1988; Parentini et al, 2005), and in plants dolichol levels are also known to increase with age (Gawarecka et al, 2022). Interestingly, the recent work of Choi et al (2023) shows that a defect in the functioning of retrograde transport from the Golgi apparatus can be the primary cause of both premature leaf senescence and enhancement of the glycosylation machinery – in line with our results which show similar effects of a primary dysfunction of the ER.…”

Divergent contribution of the MVA and MEP pathways to the formation of polyprenols and dolichols in Arabidopsis

“…They also undergo elongation to form Prens, which subsequently serve as substrates for ER-associated polyprenol reductase (PPRD2) [ 11 ]. This implies that CPT7 [ 19 ] and CPT3 [ 12 ] function independently to form Prens and Dol in Arabidopsis, similarly to the role played by two distinct CPTs in spinach leaves [ 78 ]. Such a tentative model satisfactorily explains that upon D-DX feeding, Dol-16 isotopologues in leaves are built either solely of unlabeled or labeled isoprene units.…”

“…A recent study has revealed that leaves of Arabidopsis thaliana contain a family of Prens composed of 9 to 11 isoprene units (Pren-9 to Pren-11) synthesized by CPT7. The Dol spectrum in A. thaliana (studied in hairy roots) comprises two main families: medium-length Dols (Dol-15, -16 and -17, synthesized by CPT3 [ 12 ]) and longer ones (Dol-20 to Dol-24, produced by CPT1 [ 13 ]), all of which are accompanied by traces of corresponding Prens [ 14 ]. The composition of polyisoprenoid mixtures is believed to be regulated by tissue-specific expression of dedicated CPT(s); in the Arabidopsis genome nine potential members of this multigene family have been identified [ 15 ].…”

Plant biochemical genetics in the multiomics era

“…Whilst many genes involved in plant metabolism pathways have been identified and cloned through large-scale GWAS, there are some examples of smaller-scale studies achieving good results. For example, the pathways of saiginols (phenylacylated flavonols) ( Tohge et al ., 2016 ) and dolichols in Arabidopsis ( Gawarecka et al , 2022 ), lignin precursors in Arabidopsis, maize, and poplar ( Vanholme et al , 2019 ), and steroidal glycoalkaloids in solanaceous species ( Schwahn et al , 2014 ) have all been refined by comparisons of only a handful up to around 100 genotypes. In principal, mapping of an unknown compound to a gene gives hints as to the structure of that compound, especially in cases where the gene encodes an enzyme involved in the biosynthesis pathway.…”