Xi Cai-Cai, Gu Wei, Sun Hong-Mei, Tian Rong, Liu Qi, Wang Xiao-Hao
College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
Zhongguo Zhong Yao Za Zhi. 2018 Dec;43(24):4842-4849. doi: 10.19540/j.cnki.cjcmm.2018.0128.
Selaginella tamariscina is a typical resuscitation medicinal plant with extreme drought tolerance. Trehalose plays an important role in the resurrection process, and the trehalose-6-phosphate synthase(TPS) is the key enzyme to synthesize trehalose in plants. In this study, the sequence of TPS was obtained by splicing from the transcriptome data of S. tamariscina. After the synthesis of cDNA based on the template of total RNA, the sequence was cloned by RT-PCR for verification and then analyzed by bioinformatics methods. The results indicated that the full-length coding sequence of StTPS was 2 799 bp (GenBank accession no. MH155231), and the encoded protein contained 932 amino acids. StTPS could be located in the chloroplastid according to subcellular localization prediction. There were two conserved domains belonging to glycogen phosphorylase glycosyltransferase (GPGTF) family but no signal peptide or transmembrane domain in StTPS. The expression of StTPS was determined by qRT-PCR and the variation of trehalose content was measured by HPLC-ELSD during the resurrection process of S. tamariscina. Meanwhile, the correlation between them was analyzed. The results showed that both the expression level of StTPS and the trehalose content increased associated with the extension of dehydration time, and declined associated with the extension of rehydration time which proved a significant positive correlation between the StTPS expression level and the trehalose content. The results suggested that the StTPS probably plays a central role in recovery process in S. tamariscina.
卷柏是一种典型的具有极强耐旱能力的复苏型药用植物。海藻糖在其复苏过程中发挥着重要作用，而海藻糖 -6-磷酸合酶（TPS）是植物中合成海藻糖的关键酶。在本研究中，通过对卷柏转录组数据进行拼接获得了TPS序列。以总RNA为模板合成cDNA后，通过RT-PCR克隆该序列进行验证，然后采用生物信息学方法进行分析。结果表明，StTPS的全长编码序列为2799 bp（GenBank登录号：MH155231），编码的蛋白质包含932个氨基酸。根据亚细胞定位预测，StTPS可定位于叶绿体。StTPS中有两个属于糖原磷酸化酶糖基转移酶（GPGTF）家族的保守结构域，但没有信号肽或跨膜结构域。在卷柏的复苏过程中，通过qRT-PCR测定StTPS的表达，采用HPLC-ELSD测定海藻糖含量的变化。同时，分析了它们之间的相关性。结果表明，随着脱水时间的延长，StTPS的表达水平和海藻糖含量均升高，而随着复水时间的延长则下降，这证明StTPS表达水平与海藻糖含量之间存在显著正相关。结果表明，StTPS可能在卷柏的复苏过程中起核心作用。
