Identification and characterization of a second isogene encoding γ-terpinene synthase in Thymus caespititius

Marta D. Mendes, José G. Barroso, M. Margarida Oliveira, Helena Trindade

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Thymus caespititius Brot. is an Iberian endemic species, whose essential oils possess high polymorphism. They consist mostly of mono- and sesquiterpene, some of them with interest for the pharmaceutical and food industries. The search for terpene synthase genes was performed in three in vitro T. caespititius genotypes. For these plants, the expression of a previously described γ-terpinene synthase gene, Tctps2, was confirmed, occurring concomitantly with a new gene encoding an enzyme with similar activity, named Thymus caespititius terpene synthase 4 (Tctps4). The two isogenes were isolated and functionally characterized in the three plant genotypes. Alignment of the two Tctps revealed a transit peptide much shorter in Tctps4 than in Tctps2 (3-4 amino acids instead of 47). The Tctps4 open reading frame is shorter than Tctps2 (1665 bp versus 1794 bp). The amino acid sequence of both γ-terpinene synthases shared an 88% pairwise identity. The fact that T. caespititius carries two isogenes for γ-terpinene synthases, suggests gene duplication along the evolutionary process, followed by mutations leading to the differentiation of both genes. These mutations didn't compromise protein activity. A high accumulation of transcripts from both genes was found in shoots of in vitro plantlets, while in roots they could not be detected. Still, γ-terpinene levels in aerial parts were reduced, probably due to fast conversion into carvacrol and thymol, the main components from T. caespititius essential oils. This study is a contribution to the identification of terpene synthase genes in Lamiaceae.

Original languageEnglish
Pages (from-to)1017-1027
Number of pages11
JournalJournal Of Plant Physiology
Volume171
Issue number12
DOIs
Publication statusPublished - 15 Jul 2014

Keywords

  • Chemotypes
  • In vitro culture
  • Lamiaceae
  • Monoterpene
  • Terpene synthases

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