外源茉莉酸对盐芥芥子油苷含量与抗氧化特性的影响

Effects of exogenous jasmonic acid on glucosinolate content and antioxidant properties of Eutrema salsugineum

芥子油苷是十字花科植物中的一类重要的次生代谢产物,合成的种类具有种属特异性,而且合成途径受到水杨酸、茉莉酸等植物激素的调节。盐芥(Eutrema salsugineum)是十字花科一种盐生植物,含有丰富的芥子油苷,尽管与拟南芥(Arabidopsis thaliana)亲缘关系很近,但芥子油苷种类含量存在很大差异。本研究采用200μmol·L-1的茉莉酸甲酯(methyl jasmonate, MeJA)溶液喷洒处理培养6周的盐芥幼苗,分析了处理后不同时间芥子油苷含量、合成相关基因表达、抗氧化能力的变化。结果表明, MeJA能够显著促进脂肪族和芳香族芥子油苷的积累,而吲哚族芥子油苷含量未受影响,与此同时,同一类别芥子油苷的不同组分对MeJA的响应也存在显著差异。实时荧光定量PCR分析结果显示,外源MeJA激活了体内茉莉酸信号途径,通过调控芥子油苷合成途径关键转录因子,进一步影响了芥子油苷含量的变化。此外,MeJA处理对盐芥花青素和总多酚的积累有一定的促进作用,能够提高植物抗氧化活性。

Glucosinolates(GSLs) are important secondary metabolites in cruciferous plants. The biosynthesis of GSLs is species-specific and the synthesis pathway is regulated by plant hormones such as salicylic acid and jasmonic acid. Eutrema salsugineum is a halophyte of cruciferous family, which is rich in GSLs. Although it is closely related to Arabidopsis thaliana, the content of GSLs is very different between them. To explore the effect of exogenous jasmonic acid on the biosynthesis of GSLs, the expression of GSLs regulatory genes and antioxidative capacity of E. salsugineum, 6-week-old E. salsugineum was treated with 200 μmol·L-1 methyl jasmonate(MeJA). The results shown that MeJA can significantly induce the biosynthesis of aliphatic and aromatic GSLs but not indole GSLs. MeJA also largely affect the content distribution of each component of GSLs, even if the different components of the same type GSLs. The analysis of gene expression revealed that Me JA affect the accumulation of GSLs might be correlated with the respond of the key transcriptional regulators involved in GSLs biosynthesis pathway. Furthermore, MeJA treatment promoted the produce of anthocyanins and total polyphenols, which can improve the antioxidative properties of plants.