Phenylalanine ammonia lyase (PAL) is the first enzyme of phenylpropanoid pathway. In the present study, a full-length PAL transcript from Vanda coerulea Griff. ex Lindl. (Family: Orchidaceae) was isolated and characterized. It was found that complete PAL transcript of V. coerulea (VcPAL; Gene Bank no. MG745168) contained 2175 bp with the open reading frame (ORF) of 2112 bp, encoding 703 amino acid residues. The multiple sequence alignment showed that VcPAL protein had 81% identity with that of the orchid, Bromheadia finlaysoniana. Phylogenetic analysis also disclosed that VcPAL shared the same evolutionary relationship with PAL proteins of other orchid species and to be closely related to that of other angiosperm species as well. The three-dimensional structure of VcPAL was found to be homo-tetrameric in nature consisting of four identical subunits with a molecular mass of 75 kDa per subunit. In silico characterization revealed the deduced protein to be a stable protein, comprising three major functional domains as reported in PAL proteins of other species. The transcription profiling of VcPAL exhibited the highest expression level to be present in the in vitro - raised leaf and root samples as compared to that of the ex vitro plant. The differential expression of VcPAL transcript was observed to be up-regulated by different types of abiotic stresses like wounding, cold, UV-B, salinity, and down-regulated by dark treatment. The study also exhibited that the VcPAL enzyme activity was directly proportional to the gene expression after the tissues were subjected to salinity and wounding stresses wherein a 1.7- fold increase in the enzyme activity was recorded in the leaf tissues exposed to salinity stress. A positive correlation could be found between the enzyme activity and the accumulation of phenylpropanoids such as total phenolic and flavonoid contents with R2 = 0.85 and 0.842 respectively.

中文翻译：

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药用兰花 Vanda coerulea Griff 中非生物胁迫对苯丙氨酸解氨酶 (PAL) 的计算机表征和转录​​调节。前林德尔。

苯丙氨酸解氨酶（PAL）是苯丙烷途径的第一种酶。在本研究中，来自 Vanda coerulea Griff 的全长 PAL 转录本。前林德尔。（科：兰科）被分离出来并进行了表征。发现蓝藻的完整 PAL 转录本（VcPAL；基因库编号 MG745168）包含 2175 bp，开放阅读框（ORF）为 2112 bp，编码 703 个氨基酸残基。多序列比对表明，VcPAL 蛋白与兰花 Bromheadia finlaysoniana 具有 81% 的同一性。系统发育分析还表明，VcPAL 与其他兰花物种的 PAL 蛋白具有相同的进化关系，并且与其他被子植物物种的 PAL 蛋白也具有密切的相关性。发现 VcPAL 的三维结构本质上是同源四聚体，由四个相同的亚基组成，每个亚基的分子量为 75 kDa。计算机表征显示推导的蛋白质是一种稳定的蛋白质，包括在其他物种的 PAL 蛋白质中报道的三个主要功能域。与离体植物相比，VcPAL 的转录谱表现出在离体培养的叶和根样品中存在的最高表达水平。观察到 VcPAL 转录本的差异表达被不同类型的非生物胁迫如伤人、寒冷、UV-B、盐度和暗处理下调。该研究还表明，VcPAL 酶活性与组织经受盐分和创伤胁迫后的基因表达成正比，其中在暴露于盐分胁迫的叶组织中记录到酶活性增加了 1.7 倍。酶活性与苯丙烷类物质（如总酚和黄酮类化合物的含量）的积累呈正相关，R2 分别为 0.85 和 0.842。