The abiotic stress such as water, temperature, and drought influences the production of pharmacologically important secondary metabolites of plant as a defense mechanism. Cassia angustifolia Vahl. is a potent medicinal plant which yields sennosides from its leaves and pods and grow well under water stress condition. Its leaves and pods are used for the treatment of habitual constipation as a safe herbal laxative. The present study aimed to determine the response of Cassia angustifolia Vahl. to water stress in terms of expression of targeted genes involved in the synthesis of its major secondary metabolites i.e., sennosides. The four moisture regimes i.e., 60% available soil moisture (ASM), 40% ASM, 20% ASM, and rainfed along with control were imposed from 20 days after seed sowing to the harvesting of the crop. The four ages of the plant (60 days, 75 days, 90 days, and 105 days) were taken for evaluation of differential gene expression due to water stress. Results demonstrated that water stress significantly affected the morphophysiological characters, sennoside content and gene expression. Sennosides determination was done by performing HPLC, which showed an increasing trend with increasing moisture stress. Proline, MDA, carotenoid, and electrolyte leakage were also increased in support of sennoside increment at higher moisture stress conditions. The gene expression, stress enzymes, and morphophysiological parameters such as chlorophyll, carotenoid, and Fv/Fm demonstrated a significant correlation of sennoside content. The RT-PCR analysis showed the upregulation of genes associated with the Mevalonate (HMGR, PMK), Shikimate (SDH, SMK, CS), Menaquinone (menF), and Glycosylation (UDPG) pathways at rainfed and 20% ASM conditions, suggesting their involvement in increased secondary metabolite production under moisture stress conditions. However, plant age does not have any significant effect on gene expression.

水、温度和干旱等非生物胁迫作为防御机制影响植物药理上重要的次生代谢产物的产生。决明子。是一种有效的药用植物，可从其叶子和豆荚中产生番泻苷，并在水分胁迫条件下生长良好。它的叶子和豆荚作为一种安全的草药泻药用于治疗习惯性便秘。本研究旨在确定决明子的反应瓦尔。根据参与其主要次生代谢物（即番泻苷）合成的靶基因的表达来应对水分胁迫。从种子播种后 20 天到作物收获，实施了四种水分状态，即 60% 有效土壤水分 (ASM)、40% ASM、20% ASM 和雨养和对照。取植物的四个年龄（60 天、75 天、90 天和 105 天）用于评估由于水分胁迫引起的差异基因表达。结果表明，水分胁迫显着影响形态生理特征、番泻苷含量和基因表达。Sennosides 的测定是通过执行 HPLC 来完成的，它显示出随着水分胁迫的增加而增加的趋势。脯氨酸、MDA、类胡萝卜素、和电解质泄漏也增加，以支持在较高的水分胁迫条件下增加番泻苷。基因表达、应激酶和叶绿素、类胡萝卜素和 Fv/Fm 等形态生理学参数与番泻苷含量显着相关。RT-PCR 分析显示与甲羟戊酸相关的基因上调（HMGR、PMK )、莽草酸(SDH、SMK、CS)、甲基萘醌(menF)和糖基化(UDPG)途径在雨养和 20% ASM 条件下，表明它们参与了水分胁迫条件下次生代谢产物产量的增加。然而，植物年龄对基因表达没有任何显着影响。