Malhotra Nikhil, Kumar Varun, Sood Hemant, Singh Tiratha Raj, Chauhan Rajinder Singh
Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat 173234, Himachal Pradesh, India.
Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat 173234, Himachal Pradesh, India.
Phytochemistry. 2014 Dec;108:26-34. doi: 10.1016/j.phytochem.2014.08.025. Epub 2014 Sep 16.
Aconitum heterophyllum Wall, popularly known as Atis or Patis, is an important medicinal herb of North-Western and Eastern Himalayas. No information exists on molecular aspects of aconites biosynthesis, including atisine- the major chemical constituent of A. heterophyllum. Atisine content ranged from 0.14% to 0.37% and total alkaloids (aconites) from 0.20% to 2.49% among 14 accessions of A. heterophyllum. Two accessions contained the highest atisine content with 0.30% and 0.37% as well as the highest alkaloids content with 2.22% and 2.49%, respectively. No atisine was detected in leaves and shoots of A. heterophyllum, thereby, suggesting that the biosynthesis and accumulation of aconite alkaloids occur mainly in roots. Quantitative expression analysis of 15 genes of MVA/MEP pathways in roots versus shoots, differing for atisine content (0-2.2 folds) showed 11-100 folds increase in transcript amounts of 4 genes of MVA pathway; HMGS, HMGR, PMK, IPPI, and 4 genes of MEP pathway; DXPS, ISPD, HDS, GDPS, respectively. The overall expression of 8 genes decreased to 5-12 folds after comparative expression analysis between roots of high (0.37%) versus low (0.14%) atisine content accessions, but their relative transcript amounts remained higher in high content accessions, thereby implying their role in atisine biosynthesis and accumulation. PCA analysis revealed a positive correlation between MVA/MEP pathways genes and alkaloids content. The current study provides first report wherein partial sequences of 15 genes of MVA/MEP pathways have been cloned and studied for their possible role in aconites biosynthesis. The outcome of study has potential applications in the genetic improvement of A. heterophyllum.
喜马拉雅乌头（Aconitum heterophyllum Wall），俗称阿提斯（Atis）或帕蒂斯（Patis），是喜马拉雅山脉西北部和东部的一种重要药用植物。关于乌头生物碱生物合成的分子方面，包括异叶乌头的主要化学成分阿替生，目前尚无相关信息。在14份异叶乌头种质中，阿替生含量在0.14%至0.37%之间，总生物碱（乌头生物碱）含量在0.20%至2.49%之间。两份种质的阿替生含量最高，分别为0.30%和0.37%，生物碱含量也最高，分别为2.22%和2.49%。在异叶乌头的叶片和嫩枝中未检测到阿替生，这表明乌头生物碱的生物合成和积累主要发生在根部。对根部和嫩枝中MVA/MEP途径的15个基因进行定量表达分析，二者阿替生含量不同（0 - 2.2倍），结果显示MVA途径的4个基因（HMGS、HMGR、PMK、IPPI）和MEP途径的4个基因（DXPS、ISPD、HDS、GDPS）的转录量增加了11 - 100倍。在阿替生含量高（0.37%）与低（0.14%）的种质的根部进行比较表达分析后，8个基因的整体表达下降至5 - 12倍，但它们在高含量种质中的相对转录量仍然较高，这意味着它们在阿替生生物合成和积累中发挥作用。主成分分析揭示了MVA/MEP途径基因与生物碱含量之间存在正相关。本研究首次报道了克隆MVA/MEP途径的15个基因的部分序列，并研究了它们在乌头生物碱生物合成中的可能作用。该研究结果在异叶乌头的遗传改良方面具有潜在应用价值。
