花榈木是中国传统中药,其代谢产物常用于治疗跌打损伤,具有重要的药用价值,然而目前人们对花榈木的药用化学成分如生物碱合成并不清楚。本研究对花榈木不同组织进行了代谢组和转录组学分析,结果表明花榈木中含有的生物碱大部分属于喹诺...花榈木是中国传统中药,其代谢产物常用于治疗跌打损伤,具有重要的药用价值,然而目前人们对花榈木的药用化学成分如生物碱合成并不清楚。本研究对花榈木不同组织进行了代谢组和转录组学分析,结果表明花榈木中含有的生物碱大部分属于喹诺里西啶类生物碱(Quinolizidine Alkaloids,QA)。进一步分析发现,QA生物合成的2个关键酶,赖氨酸脱羧酶(LDC)和铜胺氧化酶(CAO)在生物碱合成中起重要作用。结合花榈木转录组结果对其编码基因克隆,得到了1290 bp、2268 bp CDS序列,分别命名为OhpLDC和OhpCAO1。生物信息学分析结果表明,OhpLDC和OhpCAO1编码的蛋白质相对分子质量分别为4.63×10^(4)和8.44×10^(4),均无跨膜区域和信号肽。OhpLDC编码的氨基酸序列具有保守的底物结合位点Phe340,分析发现OhpLDC与豆科植物中的LDC基因在进化上具有较近的亲缘关系。OhpCAO1编码的氨基酸序列中具有保守结构域“NY-Y”,以及3个组氨酸保守位点,与狭叶羽扇豆的CAO1亲缘关系最近。本研究结果为解析花榈木QA的生物合成途径提供了重要基础。展开更多
Polyamines （PA）, polyamine oxidases, copper amine oxidases, and nitric oxide （NO） play important roles in physiology and stress responses in plants. NO biosynthesis as a result of catabolism of PA by polyamine oxi...Polyamines （PA）, polyamine oxidases, copper amine oxidases, and nitric oxide （NO） play important roles in physiology and stress responses in plants. NO biosynthesis as a result of catabolism of PA by polyamine oxidases and copper amine oxidases may explain in part PA-mediated responses. Involvement of a copper amine oxidase gene, COPPER AMINE OXIDASEI （CuAO1）, of Arabidopsis was tested for its role in stress responses using the knockouts cuao1-1 and cuaol-2. PA-induced and ABA-induced NO production investigated bY fluorometry and fluorescence microscopy showed that the cuaol-1 and cuaol-2 are impaired in NO production, suggesting a function of CuAO1 in PA and ABA-mediated NO production. Furthermore, we found a PA-dependent increase in protein S-nitrosylation. The addition of PA and ABA also resulted in H2O2 increases, cuao1-1 and cuao1-2 showed less sensitivity to exogenous ABA supplementation during germination, seedling establishment, and root growth inhibition as compared to wild-type. In response to ABA treatment, expression levels of the stress-responsive genes RD29A and ADH1 were significantly lower in the knockouts. These observations characterize cuao1-1 and cuao1-2 as ABA-insensitive mutants. Taken together, our findings extend the ABA signal transduction network to include CuAO1 as one potential contributor to enhanced NO production by ABA.展开更多
文摘花榈木是中国传统中药,其代谢产物常用于治疗跌打损伤,具有重要的药用价值,然而目前人们对花榈木的药用化学成分如生物碱合成并不清楚。本研究对花榈木不同组织进行了代谢组和转录组学分析,结果表明花榈木中含有的生物碱大部分属于喹诺里西啶类生物碱(Quinolizidine Alkaloids,QA)。进一步分析发现,QA生物合成的2个关键酶,赖氨酸脱羧酶(LDC)和铜胺氧化酶(CAO)在生物碱合成中起重要作用。结合花榈木转录组结果对其编码基因克隆,得到了1290 bp、2268 bp CDS序列,分别命名为OhpLDC和OhpCAO1。生物信息学分析结果表明,OhpLDC和OhpCAO1编码的蛋白质相对分子质量分别为4.63×10^(4)和8.44×10^(4),均无跨膜区域和信号肽。OhpLDC编码的氨基酸序列具有保守的底物结合位点Phe340,分析发现OhpLDC与豆科植物中的LDC基因在进化上具有较近的亲缘关系。OhpCAO1编码的氨基酸序列中具有保守结构域“NY-Y”,以及3个组氨酸保守位点,与狭叶羽扇豆的CAO1亲缘关系最近。本研究结果为解析花榈木QA的生物合成途径提供了重要基础。
文摘Polyamines （PA）, polyamine oxidases, copper amine oxidases, and nitric oxide （NO） play important roles in physiology and stress responses in plants. NO biosynthesis as a result of catabolism of PA by polyamine oxidases and copper amine oxidases may explain in part PA-mediated responses. Involvement of a copper amine oxidase gene, COPPER AMINE OXIDASEI （CuAO1）, of Arabidopsis was tested for its role in stress responses using the knockouts cuao1-1 and cuaol-2. PA-induced and ABA-induced NO production investigated bY fluorometry and fluorescence microscopy showed that the cuaol-1 and cuaol-2 are impaired in NO production, suggesting a function of CuAO1 in PA and ABA-mediated NO production. Furthermore, we found a PA-dependent increase in protein S-nitrosylation. The addition of PA and ABA also resulted in H2O2 increases, cuao1-1 and cuao1-2 showed less sensitivity to exogenous ABA supplementation during germination, seedling establishment, and root growth inhibition as compared to wild-type. In response to ABA treatment, expression levels of the stress-responsive genes RD29A and ADH1 were significantly lower in the knockouts. These observations characterize cuao1-1 and cuao1-2 as ABA-insensitive mutants. Taken together, our findings extend the ABA signal transduction network to include CuAO1 as one potential contributor to enhanced NO production by ABA.
