Siderophore-mediated upregulation of Arabidopsis ferritin expression in response to Erwinia chrysanthemi infection
Siderophore-mediated upregulation of Arabidopsis ferritin expression in response to Erwinia chrysanthemi infection
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DOI：
10.1111/j.1365-313x.2005.02451.x
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发表时间：
2005-07-01
期刊：
影响因子：
7.2
通讯作者：
Expert, D
中科院分区：
文献类型：
--
作者：
Dellagi, A;Rigault, M;Expert, D
铁蛋白是拟南芥中由四个成员基因家族（AtFer 1 -4）编码的多聚体铁储存蛋白。为了研究铁蛋白中的铁螯合是否是细菌入侵诱导的铁抑制防御系统的一部分，我们使用拟南芥作为致病性细菌欧文氏菌的易感宿主。在这项研究中，我们使用了T-DNA插入突变体系，以表明一个功能性AtFer 1基因的缺乏导致拟南芥植物对大肠杆菌的敏感性增强。查里岛我们发现，AtFer 1基因在感染过程中上调，在感染后0.5和24小时（p.i.）的关键时间点的转录物的双相积累。在感染后24 h观察到AtFer 1表达的激活。是独立的铁依赖性调控序列（IDRS）已知介导的AtFer 1基因的转录反应，铁过剩和一氧化氮。AtFer 1基因表达的上调在接种E. chorii铁载体无效突变体。渗透的纯化的铁载体chrysobactin和desferrioxamine强烈增加AtFer 1转录丰度，它没有发生与这些铁载体的铁负载形式。我们发现，无论是氧化应激，也没有一氧化氮参与植物对金杆菌素的反应。我们的数据表明，铁蛋白的积累过程中感染拟南芥E。Chroni是主要由细菌铁载体激活的基础防御机制。铁载体在这一过程中的潜在作用进行了讨论。
Ferritins are multimeric iron storage proteins encoded by a four-member gene family in Arabidopsis (AtFer1-4). To investigate whether iron sequestration in ferritins is a part of an iron-withholding defense system induced in response to bacterial invasion, we used Arabidopsis thaliana as a susceptible host for the pathogenic bacterium Erwinia chrysanthemi. In this study, we used a T-DNA insertion mutant line to show that the lack of a functional AtFer1 gene resulted in an enhanced susceptibility of Arabidopsis plants to E. chrysanthemi. We found that the AtFer1 gene is upregulated during infection, with a biphasic accumulation of the transcript at critical time points 0.5 and 24 h post-infection (p.i.). The activation of AtFer1 expression observed at 24 h p.i. was independent of the iron-dependent regulatory sequence (IDRS) known to mediate the transcriptional response of the AtFer1 gene to iron excess and to nitric oxide. Upregulation of AtFer1 gene expression was compromised after inoculation with an E. chrysanthemi siderophore null mutant. Infiltration of the purified siderophores chrysobactin and desferrioxamine strongly increased AtFer1 transcript abundance and it did not occur with the iron-loaded forms of these siderophores. We found that neither oxidative stress nor nitric oxide was involved in the plant response to chrysobactin. Our data show that ferritin accumulation during infection of Arabidopsis by E. chrysanthemi is a basal defense mechanism which is mainly activated by bacterial siderophores. The potential role of siderophores in this process is discussed.