Departmento de Biologia Vegetal, Faculdade de Ciências, Centro de Biotecnologia Vegetal, Instituto de Biotecnologia e Bioengenharia, Universidade de Lisboa, C2, Campo Grande, 1749-016 Lisbon, Portugal.
Planta. 2013 Jul;238(1):191-204. doi: 10.1007/s00425-013-1884-2. Epub 2013 Apr 28.
The identification, isolation and functional characterization of two genes encoding two monoterpene synthases-γ-terpinene synthase (Tctps2) and α-terpineol synthase (Tctps5)-from three chemically distinct Thymus caespititius (Lamiaceae) genotypes were performed. Genomic exon-intron structure was also determined for both terpene synthase genes, revealing an organization with seven exons and six introns. The cDNA of Tctps2 was 2,308 bp long and had an open reading frame of 1,794 bp encoding for a protein with 598 amino acids. Tctps5 was longer, mainly due to intron sequences, and presented high intraspecific variability on the plants analyzed. It encoded for a protein of 602 amino acids from an open reading frame of 1,806 bp comprising a total of 2,507 bp genomic sequence. The amino acid sequence of these two active Tctps genes shared 74 % pairwise identity, ranging between 42 and 94 % similarity with about 50 known terpene synthases of other Lamiaceae species. Gene expression revealed a multi-product Tctps2 and Tctps5 enzymes, producing γ-terpinene and α-terpineol as major components, respectively. These enzymatic results were consistent with the monoterpene profile present in T. caespititius field plants, suggesting a transcriptional regulation in leaves. Herewith reported for the first time for this species, these two newly characterized Tctps genes improve the understanding of the molecular mechanisms of reaction responsible for terpene biosynthesis and chemical diversity found in T. caespititius.
从三个化学上不同的 Thymus caespititius（唇形科）基因型中鉴定、分离和功能表征了编码两种单萜合酶-γ-萜品烯合酶（Tctps2）和α-松油醇合酶（Tctps5）的两个基因。还确定了这两个萜烯合酶基因的基因组外显子-内含子结构，揭示了一个具有七个外显子和六个内含子的组织。Tctps2 的 cDNA 长 2,308 bp，开放阅读框长 1,794 bp，编码 598 个氨基酸的蛋白质。Tctps5 更长，主要是由于内含子序列，并且在所分析的植物中具有高度的种内变异性。它编码一个由 1,806 bp 组成的开放阅读框编码的 602 个氨基酸的蛋白质，总共有 2,507 bp 的基因组序列。这两个活性 Tctps 基因的氨基酸序列共享 74%的成对同一性，与其他 Lamiaceae 物种的约 50 种已知萜烯合酶的相似度在 42%至 94%之间。基因表达显示多产物 Tctps2 和 Tctps5 酶，分别产生 γ-萜品烯和 α-松油醇作为主要成分。这些酶学结果与 T. caespititius 田间植物中存在的单萜谱一致，表明在叶片中存在转录调控。这两个新表征的 Tctps 基因首次在该物种中报道，提高了对负责萜类生物合成和 T. caespititius 中发现的化学多样性的反应分子机制的理解。
