Modolo Luzia V, Augusto Ohara, Almeida Irene M G, Magalhaes Jose R, Salgado Ione
Departamento de Bioquímica, Instituto de Biologia, Universidade Estadual de Campinas, CP 6109, Campinas, SP 13083-970, Brazil.
FEBS Lett. 2005 Jul 4;579(17):3814-20. doi: 10.1016/j.febslet.2005.05.078.
The origin of nitric oxide (*NO) in plants is unclear and an *NO synthase (NOS)-like enzyme and nitrate reductase (NR) are claimed as potential sources. Here we used wild-type and NR-defective double mutant plants to investigate *NO production in Arabidopsis thaliana in response to Pseudomonas syringae pv maculicola. NOS activity increased substantially in leaves inoculated with P. syringae. However, electron paramagnetic resonance experiments showed a much higher *NO formation that was dependent on nitrite and mitochondrial electron transport rather than on arginine or nitrate. Overall, these results indicate that NOS, NR and a mitochondrial-dependent nitrite-reducing activity cooperate to produce *NO during A. thaliana-P. syringae interaction.
植物中一氧化氮（NO）的来源尚不清楚，一种类似一氧化氮合酶（NOS）的酶和硝酸还原酶（NR）被认为是潜在来源。在这里，我们使用野生型和NR缺陷型双突变体植物来研究拟南芥在响应丁香假单胞菌番茄致病变种时的NO产生情况。接种丁香假单胞菌的叶片中NOS活性大幅增加。然而，电子顺磁共振实验表明，NO的形成量要高得多，这取决于亚硝酸盐和线粒体电子传递，而不是精氨酸或硝酸盐。总体而言，这些结果表明，在拟南芥与丁香假单胞菌相互作用期间，NOS、NR和线粒体依赖性亚硝酸盐还原活性协同作用以产生NO。
