Aluminum-induced cell wall peroxidase activity and lignin synthesis are differentially regulated by jasmonate and nitric oxide.
Aluminum-induced cell wall peroxidase activity and lignin synthesis are differentially regulated by jasmonate and nitric oxide.
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DOI：
10.1021/jf802001v
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发表时间：
2008-09
影响因子：
6.1
通讯作者：
Y. Xue;L. Tao;Z. Yang
中科院分区：
文献类型：
--
作者：
Y. Xue;L. Tao;Z. Yang
决明子是一种一年生豆科植物，作为一种传统的中草药种植，具有多种治疗作用，包括调节血压和血脂。由于中国东南部自然形成的酸性土壤，这种植物可能具有耐低pH和铝毒的策略。为了寻找铝胁迫下生化反应的调控基础，研究了黄连根尖细胞壁结合的过氧化物酶，包括木质素产生的过氧化物酶和NADH氧化酶。两种过氧化物酶活性均随铝浓度的升高而显著升高。天然PAGE分析也表明铝对细胞壁过氧化物酶有较强的诱导作用。铝诱导的过氧化物酶活性升高与木质素积累和过氧化氢产生密切相关。研究了外源一氧化氮(NO)和甲基茉莉酸(MJ)对铝胁迫下的信号特性和木质素合成的生化效应。10微米的MJ通过激活质外体过氧化物酶活性和积累H2 O2和木质素来增强根系对铝的敏感性，而NO的作用则相反。铝胁迫下质外体过氧化物酶的敏感性与MJ和NO信号的相互作用有关。分析表明，在铝暴露的根中，脂肪氧合酶(一种合成MJ的酶)的活性在没有暴露的情况下受到抑制，其转录增加。并观察了MJ对细胞内NO生成的影响。结果表明，Al对4，5-二氨基荧光素二乙酸酯的NO染色有增强作用，而MJ对NO染色有抑制作用。这些结果表明，NO和MJ可能在铝胁迫下根细胞壁过氧化物酶活性和木质素合成的信号转导中相互作用。
Cassia tora is an annual legume and cultivated as a traditional medicinal herb for multiple therapies including regulation of blood pressure and blood lipid. Because of naturally occurring acidic soils in southeastern China, this plant species may possess strategies for tolerance to low pH and aluminum toxicity. In the search for the regulatory basis of biochemical response to Al, cell wall-bound peroxidases, including lignin-generated peroxidases and NADH oxidases, were investigated in the root tips of C. tora. Activities of both types of peroxidases significantly increased with Al concentrations. Analysis with native PAGE also demonstrated the strong induction of cell wall peroxidases by Al. The Al-induced increasing activities of peroxidases were closely correlated with lignin accumulation and H 2O 2 production. The biochemical effect of exogenous nitric oxide (NO) and methyl jasmonic acid (MJ) was examined to investigate signal properties and lignin synthesis under Al stress. Application of MJ at 10 microM promoted root sensitivity to Al by activating apoplastic peroxidase activity and accumulating H 2O 2 and lignin, whereas the opposite action was found for NO. The sensitivity of apoplastic peroxidases under Al stress was associated with the cross-talk of MJ and NO signals. The analysis reveals that the activity of lipoxygenase (an enzyme for MJ biosynthesis), with its transcripts increased in Al-exposed roots, was depressed by NO exposure. The effect of MJ on intracellular NO production was also investigated. It is shown that NO staining with 4,5-diaminofluorescein diacetate fluorescence was intensified by Al but was suppressed by MJ. These results suggest that NO and MJ may interplay in signaling the cell wall peroxidase activity and lignin synthesis in the roots exposed to Al.