The effect of silymarin as an active ingredient of milk thistle seed as an systemic acquired resistance (SAR) substance in rice (Oryza sativa L.) against rice blast disease caused by Magnaporthe oryzae was investigated in this study. Silymarin is considered as a medication substance on human drug and has a metabolic and cell-regulating effect and scavenging oxygen radicals reactions. Results showed that, silymarin do not inhibits fungus linear growth in vitro. Significant improvement of resistance under greenhouse conditions with different concentrations 10, 25, 50, 125, 250, 500, 1000 and 2000 mg/L of silymarin was recorded. The most suitable concentration was 500 mg/L. The recorded disease severity was 23.5% when applied five days before inoculation and significantly reduced disease severity under field condition at both experimental seasons. Gene expression for some indicators for salicylic acid (SA) pathway such as OsWRKY45 and OsNPR1, jasmonic acid (JA) pathway such as AOS2, JAMYB and PBZ1 (OsPR10) and ethylene (ET) pathway such as ACO7 was studied. Salicylic acid effect on the pathway related to salicylic acid is evident through both genes (OsWRKY45 and OsNPR1), not jasmonic acid and ethylene pathways, while the effect of silymarin is not clear through the genes studied in all pathways. Finally, the results suggested that silymarin activates SAR at least in part by reinforcing basal plant defense responses on induced defense state.

在这项研究中，研究了水飞蓟素作为水飞蓟种子的活性成分作为水稻（Oryza sativa L. ）的系统获得性抗性（SAR）物质对由Magnaporth e oryzae引起的稻瘟病的影响。水飞蓟素被认为是人类药物的药物，具有代谢和细胞调节作用以及清除氧自由基反应。结果表明，水飞蓟素在体外不抑制真菌的线性生长. 记录了在不同浓度 10、25、50、125、250、500、1000 和 2000 毫克/升水飞蓟素的温室条件下抗性的显着改善。最合适的浓度为 500 mg/L。在接种前五天应用时记录的疾病严重程度为 23.5%，并且在两个实验季节的田间条件下都显着降低了疾病严重程度。研究了水杨酸(SA)通路如OsWRKY45和OsNPR1、茉莉酸(JA)通路如AOS2、JAMYB和PBZ1(OsPR10)和乙烯(ET)通路如ACO7的一些指标的基因表达。通过两个基因（OsWRKY45 和 OsNPR1），而不是茉莉酸和乙烯途径，水杨酸对与水杨酸相关的途径的影响是明显的，而水飞蓟素的影响在所有途径中研究的基因中都不清楚。最后，