Role of salicylic acid in ochratoxin A(OTA) toxicity to Arabidopsis thaliana | 水杨酸在赭曲霉毒素A诱导的拟南芥毒性中的作用

صينى. 赭曲霉毒素A(ochratoxin A, OTA)是一种分布广泛的真菌毒素，会对谷物、动物饲料、动物性食品等造成污染。OTA对多种动物具有较强的肾毒性和肝毒性，并有致畸、致突变和致癌作用。对植物的研究表明，OTA还具有植物毒性。本实验研究了植物中重要的内源信号分子水杨酸(Salicylic acid, SA)在OTA对拟南芥(Arabidopsis thaliana)毒性中的作用。利用高效液相色谱测定了拟南芥叶片在OTA处理下SA含量的变化，结果显示，OTA胁迫促进了SA含量的上升；通过实时荧光定量PCR测定了OTA对SA途径中重要的病程相关蛋白1基因(pathogenesis-related gene 1, PR1)相对表达量的影响，结果显示，OTA能诱导PR1的表达，并且这种诱导作用与OTA胁迫时间有关；SA与OTA同时处理拟南芥叶片后，观察到SA能造成OTA引起的叶片坏死斑的加重，相对电导率和活性氧含量的测定结果表明，SA能加重OTA对叶片的伤害，促进OTA诱导的活性氧的上升。本研究表明，SA参与了OTA诱导的拟南芥毒性过程，SA和OTA共同处理能增强OTA的植物毒性。

إنجليزي. Ochratoxin A(OTA) is a widespread mycotoxin. It can contaminate cereals, animal feed, animal foodstuffs et al. OTA has been shown to be nephrotoxic, hepatotoxic, teratogenic, immunotoxic, mutagenesis and carcinogenesis to several species of animals. The plant toxicity of OTA has been discovered in recent years. In this research we focused on the involvement of salicylic acid(SA) in OTA toxicity to Arabidopsis thaliana, which is an important endogenous signal molecule of plants. SA content of A.thaliana leaves exposed to OTA was measured by high performance liquid chromatography. The results showed that OTA treatment increased SA content in A.thaliana leaves. Quantitative Real-time PCR was performed to determine the relative expression level of pathogenesis-related gene 1(PR1) which is an important gene in SA pathway. We found that PR1 expression was induced by OTA, moreover the effect of OTA was related to treatment time. When exogenous SA was treated with OTA, aggravated lesions were observed. According to results of relative leakage rate and reactive oxygen species content measurement, it was showed that SA could enhance the damage of leaves and promote reactive oxygen species production caused by OTA. The research indicates the involvement of SA in plant toxicity of OTA which can be enhanced by SA.