Coordinated activation of metabolic pathways for antioxidants and defence compounds by jasmonates and their roles in stress tolerance in Arabidopsis.
Coordinated activation of metabolic pathways for antioxidants and defence compounds by jasmonates and their roles in stress tolerance in Arabidopsis.
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DOI：
10.1111/j.1365-313x.2005.02560.x
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发表时间：
2005-10
期刊：
影响因子：
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通讯作者：
Yuko Sasaki-Sekimoto;N. Taki;T. Obayashi;M. Aono;Fuminori Matsumoto;N. Sakurai;Hideyuki Suzuki;M. Hirai;M. Noji;K. Saito;T. Masuda;K. Takamiya;D. Shibata;H. Ohta
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文献类型：
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作者：
Yuko Sasaki-Sekimoto;N. Taki;T. Obayashi;M. Aono;Fuminori Matsumoto;N. Sakurai;Hideyuki Suzuki;M. Hirai;M. Noji;K. Saito;T. Masuda;K. Takamiya;D. Shibata;H. Ohta
茉莉酸（Jasmonic acid， JA）和茉莉酸甲酯（methyl jasmonate, MeJA）统称为茉莉酸盐，是普遍存在的植物信号化合物。几种胁迫条件，如伤害和病原体感染，导致内源性茉莉酸积累和茉莉酸反应基因的表达。虽然茉莉酸盐是植物胁迫响应的重要信号成分，但其信号对植物抗逆性的作用机制尚未明确。利用包含13516个表达序列标签（est）、覆盖8384个位点的cDNA宏阵列，对拟南芥茉莉素调控的代谢途径进行了全面分析。结果表明，茉莉酸盐激活了9个代谢途径相关因子的协调基因表达，这些代谢途径属于两个功能相关的群体：抗坏血酸和谷胱甘肽代谢途径，它们在氧化应激防御反应中起重要作用；吲哚硫代葡萄糖苷的生物合成，这是一种存在于十字花科的防御化合物。我们证实JA诱导了抗坏血酸、谷胱甘肽和半胱氨酸的积累，并增加了脱氢抗坏血酸还原酶（一种抗坏血酸循环途径中的酶）的活性。已知这些抗氧化代谢途径在氧化应激条件下被激活。臭氧（O3）暴露是一种典型的氧化应激，已知可引起抗氧化代谢的激活。我们发现，O3暴露引起了野生型中几个参与抗氧化代谢的基因的诱导。然而，在茉莉酸缺乏的拟南芥12-氧植物二烯酸还原酶3 （opr3）突变体中，抗氧化基因的诱导被取消。与野生型相比，opr3突变体对O3暴露更敏感。这些结果表明，茉莉酸盐介导的代谢途径的协调激活提供了对环境胁迫的抗性。
Jasmonic acid (JA) and methyl jasmonate (MeJA), collectively termed jasmonates, are ubiquitous plant signalling compounds. Several types of stress conditions, such as wounding and pathogen infection, cause endogenous JA accumulation and the expression of jasmonate-responsive genes. Although jasmonates are important signalling components for the stress response in plants, the mechanism by which jasmonate signalling contributes to stress tolerance has not been clearly defined. A comprehensive analysis of jasmonate-regulated metabolic pathways in Arabidopsis was performed using cDNA macroarrays containing 13516 expressed sequence tags (ESTs) covering 8384 loci. The results showed that jasmonates activate the coordinated gene expression of factors involved in nine metabolic pathways belonging to two functionally related groups: (i) ascorbate and glutathione metabolic pathways, which are important in defence responses to oxidative stress, and (ii) biosynthesis of indole glucosinolate, which is a defence compound occurring in the Brassicaceae family. We confirmed that JA induces the accumulation of ascorbate, glutathione and cysteine and increases the activity of dehydroascorbate reductase, an enzyme in the ascorbate recycling pathway. These antioxidant metabolic pathways are known to be activated under oxidative stress conditions. Ozone (O3) exposure, a representative oxidative stress, is known to cause activation of antioxidant metabolism. We showed that O3 exposure caused the induction of several genes involved in antioxidant metabolism in the wild type. However, in jasmonate-deficient Arabidopsis 12-oxophytodienoate reductase 3 (opr3) mutants, the induction of antioxidant genes was abolished. Compared with the wild type, opr3 mutants were more sensitive to O3 exposure. These results suggest that the coordinated activation of the metabolic pathways mediated by jasmonates provides resistance to environmental stresses.