Transcriptional Regulation of Vitamin E Biosynthesis during Germination of Dwarf Fan Palm Seeds

Laura Siles, Leonor Alegre, Ariadna González-Solís, Edgar B. Cahoon, Sergi Munné-Bosch

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Vitamin E, a potent antioxidant either presents in the form of tocopherols and/or tocotrienols depending on the plant species, tissue and developmental stage, plays a major role in protecting lipids from oxidation in seeds. Unlike tocopherols, which have a more universal distribution, the occurrence of tocotrienols is limited primarily to monocot seeds. Dwarf fan palm (Chamaerops humilis var. humilis) seeds accumulate tocotrienols in quiescent and dormant seeds, while tocopherols are de novo synthesized during germination. Here, we aimed to elucidate whether tocopherol biosynthesis is regulated at the transcriptional level during germination in this species. We identified and quantified the expression levels of five genes involved in vitamin E biosynthesis, including TYROSINE AMINOTRANSFERASE (ChTAT), HOMOGENTISATE PHYTYLTRANSFERASE (ChHPT), HOMOGENTISATE GERANYLGERANYL TRANSFERASE (ChHGGT), TOCOPHEROL CYCLASE (ChTC) and TOCOPHEROL γ-METHYLTRANSFERASE (Chγ-TMT). Furthermore, we evaluated to what extent variations in the endogenous contents of hormones and hydrogen peroxide (H2O2) correlated with transcriptional regulation. Results showed an increase of ChTAT and ChHPT levels during seed germination, which correlated with an increase of jasmonic acid (JA), gibberellin4 (GA4), and H2O2 contents, while ChHGGT and Chγ-TMT expression levels decreased, thus clearly indicating vitamin E biosynthesis is diverted to tocopherols rather than to tocotrienols. Exogenous application of jasmonic acid increased tocopherol, but not tocotrienol content, thus confirming its regulatory role in vitamin E biosynthesis during seed germination. It is concluded that the biosynthesis of vitamin E is regulated at the transcriptional level during germination in dwarf fan palm seeds, with ChHPT playing a key role in the diversion of the vitamin E pathway towards tocopherols instead of tocotrienols.

Original languageEnglish (US)
Pages (from-to)2490-2501
Number of pages12
JournalPlant & cell physiology
Volume59
Issue number12
DOIs
StatePublished - Dec 1 2018

ASJC Scopus subject areas

  • Physiology
  • Plant Science
  • Cell Biology

Fingerprint Dive into the research topics of 'Transcriptional Regulation of Vitamin E Biosynthesis during Germination of Dwarf Fan Palm Seeds'. Together they form a unique fingerprint.

Cite this