van Wees Saskia C M, Chang Hur-Song, Zhu Tong, Glazebrook Jane
Torrey Mesa Research Institute, Syngenta Research and Technology, 3115 Merryfield Row, San Diego, California 92121, USA.
Plant Physiol. 2003 Jun;132(2):606-17. doi: 10.1104/pp.103.022186. Epub 2003 May 15.
All tested accessions of Arabidopsis are resistant to the fungal pathogen Alternaria brassicicola. Resistance is compromised by pad3 or coi1 mutations, suggesting that it requires the Arabidopsis phytoalexin camalexin and jasmonic acid (JA)-dependent signaling, respectively. This contrasts with most well-studied Arabidopsis pathogens, which are controlled by salicylic acid-dependent responses and do not benefit from absence of camalexin or JA. Here, mutants with defects in camalexin synthesis (pad1, pad2, pad3, and pad5) or in JA signaling (pad1, coi1) were found to be more susceptible than wild type. Mutants with defects in salicylic acid (pad4 and sid2) or ethylene (ein2) signaling remained resistant. Plant responses to A. brassicicola were characterized using expression profiling. Plants showed dramatic gene expression changes within 12 h, persisting at 24 and 36 h. Wild-type and pad3 plants responded similarly, suggesting that pad3 does not have a major effect on signaling. The response of coi1 plants was quite different. Of the 645 genes induced by A. brassicicola in wild-type and pad3 plants, 265 required COI1 for full expression. It is likely that some of the COI1-dependent genes are important for resistance to A. brassicicola. Responses to A. brassicicola were compared with responses to Pseudomonas syringae infection. Despite the fact that these pathogens are limited by different defense responses, approximately 50% of the induced genes were induced in response to both pathogens. Among these, requirements for COI1 were consistent after infection by either pathogen, suggesting that the regulatory effect of COI1 is similar regardless of the initial stimulus.
所有经过测试的拟南芥种质对真菌病原体链格孢菌均具有抗性。pad3或coi1突变会损害这种抗性，这表明抗性分别需要拟南芥植保素camalexin和茉莉酸（JA）依赖性信号传导。这与大多数经过充分研究的拟南芥病原体形成对比，那些病原体受水杨酸依赖性反应控制，并且缺失camalexin或JA对其并无益处。在这里，发现camalexin合成（pad1、pad2、pad3和pad5）或JA信号传导（pad1、coi1）存在缺陷的突变体比野生型更易受感染。水杨酸（pad4和sid2）或乙烯（ein2）信号传导存在缺陷的突变体仍具有抗性。利用表达谱分析对植物对链格孢菌的反应进行了表征。植物在12小时内就表现出显著的基因表达变化，在24小时和36小时时这种变化依然持续。野生型和pad3植物的反应相似，这表明pad3对信号传导没有重大影响。coi1植物的反应则大不相同。在野生型和pad3植物中由链格孢菌诱导的645个基因中，有265个基因的充分表达需要COI1。很可能一些COI1依赖性基因对于抗链格孢菌很重要。将对链格孢菌的反应与对丁香假单胞菌感染的反应进行了比较。尽管这些病原体受不同防御反应的限制，但大约50%的诱导基因对这两种病原体的感染均有反应。其中，COI1的需求在任何一种病原体感染后都是一致的，这表明无论初始刺激如何，COI1的调节作用都是相似的。
