Nitrate reductase is responsible for elicitin-induced nitric oxide production in nicotiana benthamiana
Nitrate reductase is responsible for elicitin-induced nitric oxide production in nicotiana benthamiana
复制标题
DOI：
10.1093/pcp/pcj044
复制
发表时间：
2006-06-01
影响因子：
4.9
通讯作者：
Kawakita, Kazuhito
中科院分区：
文献类型：
--
作者：
Yamamoto-Katou, Ayako;Katou, Shinpei;Kawakita, Kazuhito
最近的工作已经确定了一氧化氮（NO）在激活植物抗病性中的关键作用。硝酸还原酶（NR）是植物体内产生NO的酶之一。在以前的研究中，我们报道了病原菌信号诱导马铃薯NR基因的表达，表明NR参与病原菌信号诱导的NO产生。在这项研究中，我们克隆了NR基因从烟草本塞姆亚纳和调查他们参与的NO生产诱导INF 1，一个主要的诱导素由致病疫霉分泌。对N. INF 1处理后1-3 h，本氏烟叶片NO生成量达到最大值。INF 1诱导的NO生成完全抑制NO特异性清除剂，但部分由一氧化氮合酶抑制剂。为了研究NR参与INF 1诱导的NO产生，通过病毒诱导的基因沉默来沉默NR基因。NR沉默的植物表现出类似于拟南芥NR双突变体的特征的淡黄色叶片。NR基因的沉默显着降低了NO 2-产生活性和INF 1诱导的NO产生，表明NR参与INF 1诱导的NO产生。相反，编码N.通过农杆菌介导的瞬时表达的本塞姆氏NR提高了NO2-产生活性9倍于对照;然而，在过表达NbNR 1的原生质体中INF 1诱导的NO产生与对照原生质体中的相当。这些结果表明，NR参与INF 1诱导的NO产生，NR的翻译后修饰或底物NO2-的可用性可能是NR产生NO的限速步骤。
Recent works have established a key role for nitric oxide (NO) in activating disease resistance in plants. Nitrate reductase (NR) is one of the enzymes that are capable of producing NO in plants. In a previous study, we reported that pathogen signals induce expression of NR genes in potato, suggesting the involvement of NR in NO production induced by pathogen signals. In this study, we cloned NR genes from Nicotiana benthamiana and investigated their involvement in NO production induced by INF1, a major elicitin secreted by Phytophthora infestans. Treatment of protoplasts prepared from N. benthamiana leaves with INF1 elevated NO production to a maximum level 1-3 h after treatment. INF1-induced NO generation was suppressed completely by an NO-specific scavenger, but partially by a nitric oxide synthase inhibitor. To investigate the involvement of NR in INF1-induced NO production, NR genes were silenced by virus-induced gene silencing. The NR-silenced plants showed yellowish leaves which resemble the characteristic of Arabidopsis NR double mutants. Silencing of NR genes significantly decreased both NO2--producing activity and INF1-induced NO production, indicating that NR is involved in INF1-induced NO production. In contrast, overexpression of NbNR1 encoding N. benthamiana NR by Agrobacterium-mediated transient expression elevated NO2--producing activity nine times over the control; however, INF1-induced NO production in protoplasts overexpressing NbNR1 was comparable with that in control protoplasts. These results suggest that NR is involved in INF1-induced NO production, and post-translational modification of NR or availability of substrate NO2- may be a rate-limiting step of NO production by NR.