A key enzyme for flavin synthesis is required for nitric oxide and reactive oxygen species production in disease resistance
A key enzyme for flavin synthesis is required for nitric oxide and reactive oxygen species production in disease resistance
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DOI：
10.1111/j.0960-7412.2010.04206.x
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发表时间：
2010-06-01
期刊：
影响因子：
7.2
通讯作者：
Yoshioka, Hirofumi
中科院分区：
文献类型：
--
作者：
Asai, Shuta;Mase, Keisuke;Yoshioka, Hirofumi
一氧化氮（NO）和活性氧（ROS）在植物免疫中起着重要作用.然而，这些自由基的生产的调节机制尚未完全了解。超敏反应（HR）细胞死亡需要同时和平衡地产生NO和ROS。在这项研究中，我们确定NbRibA编码的双功能酶，鸟苷三磷酸环化水解酶II/3，4-二羟基-2-丁酮-4-磷酸合酶，参与生物合成的黄素，通过筛选相关的基因有丝分裂原活化蛋白激酶介导的细胞死亡，使用病毒诱导的基因沉默。内源性核黄素及其衍生物，黄素单核苷酸（FMN）和黄素腺嘌呤二核苷酸（FAD），这是参与氧化还原反应的几种酶的重要辅基的水平，在NbRibA沉默的本塞姆氏烟草下降。沉默NbRibA不仅损害HR细胞死亡，而且还损害由INF 1激发素和NbMEK 2的组成型活性形式（NbMEK 2DD）诱导的NO和ROS产生，并且还诱导对卵菌致病疫霉和子囊菌圆形炭疽菌的高易感性。通过添加核黄素、FMN或FAD，可以挽救NbRibA沉默叶片中INF 1诱导的自由基产生受损和HR细胞死亡。这些结果表明，黄素生物合成参与调节NO和ROS的产生，和HR细胞死亡。
P>Nitric oxide (NO) and reactive oxygen species (ROS) play key roles in plant immunity. However, the regulatory mechanisms of the production of these radicals are not fully understood. Hypersensitive response (HR) cell death requires the simultaneous and balanced production of NO and ROS. In this study we indentified NbRibA encoding a bifunctional enzyme, guanosine triphosphate cyclohydrolase II/3,4-dihydroxy-2-butanone-4-phosphate synthase, which participates in the biosynthesis of flavin, by screening genes related to mitogen-activated protein kinase-mediated cell death, using virus-induced gene silencing. Levels of endogenous riboflavin and its derivatives, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are important prosthetic groups for several enzymes participating in redox reactions, decreased in NbRibA-silenced Nicotiana benthamiana. Silencing NbRibA compromised not only HR cell death, but also the NO and ROS production induced by INF1 elicitin and a constitutively active form of NbMEK2 (NbMEK2DD), and also induced high susceptibility to oomycete Phytophthora infestans and ascomycete Colletotrichum orbiculare. Compromised radical production and HR cell death induced by INF1 in NbRibA-silenced leaves were rescued by adding riboflavin, FMN or FAD. These results indicate that flavin biosynthesis participates in regulating NO and ROS production, and HR cell death.