The cpr5 mutant of Arabidopsis expresses both NPR1-dependent and NPR1-independent resistance
The cpr5 mutant of Arabidopsis expresses both NPR1-dependent and NPR1-independent resistance
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DOI：
10.1105/tpc.9.9.1573
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发表时间：
1997-09-01
期刊：
影响因子：
11.6
通讯作者：
Dong, XN
中科院分区：
文献类型：
--
作者：
Bowling, SA;Clarke, JD;Dong, XN
cpr 5突变体是从系统获得性抗性（SAR）的组成型表达的筛选中鉴定的。这种单一的隐性突变也导致褪绿病变的自发表达和减少毛状体发育。发现cpr 5植物对两种毒性病原体（假单胞菌斑点致病变种ES 4326和寄生霜霉Noco 2）具有组成型抗性;具有病程相关基因1（PR-1）的内源表达;并且具有升高的水杨酸（SA）水平。cpr 5和SA降解细菌基因nahG或SA不敏感突变npr 1的纯合系不表达PR-1或表现出对P. s.斑点霉ES 4326。因此，我们得出结论，cpm在诱导SAR中作用于SA的上游。然而，cpr 5 npr 1植物保留了对P. parasitica Noco 2的高抗性和防御素基因PDF1.2的高表达，这意味着也发生了NPR 1非依赖性抗性信号传导。我们的结论是，cpr 5突变导致组成型表达的NPR 1依赖和NPR 1独立的SAR途径。这种突变的鉴定表明，这些途径在早期信号转导步骤中是连接的，并且它们在提供抗性方面具有重叠的功能。
The cpr5 mutant was identified from a screen for constitutive expression of systemic acquired resistance (SAR). This single recessive mutation also leads to spontaneous expression of chlorotic lesions and reduced trichome development. The cpr5 plants were found to be constitutively resistant to two virulent pathogens, Pseudomonas syringae pv maculicola ES4326 and Peronospora parasitica Noco2; to have endogenous expression of the pathogenesis-related gene 1 (PR-1); and to have an elevated level of salicylic acid (SA). Lines homozygous for cpr5 and either the SA-degrading bacterial gene nahG or the SA-insensitive mutation npr1 do not express PR-1 or exhibit resistance to P. s. maculicola ES4326. Therefore, we conclude that cpm acts upstream of SA in inducing SAR. However, the cpr5 npr1 plants retained heightened resistance to P. parasitica Noco2 and elevated expression of the defensin gene PDF1.2, implying that NPR1-independent resistance signaling also occurs. We conclude that the cpr5 mutation leads to constitutive expression of both an NPR1-dependent and an NPR1-independent SAR pathway. Identification of this mutation indicates that these pathways are connected in early signal transduction steps and that they have overlapping functions in providing resistance.