Detached and attached Arabidopsis leaf assays reveal distinctive Defense responses against hemibiotrophic Colletotrichum spp.
Detached and attached Arabidopsis leaf assays reveal distinctive Defense responses against hemibiotrophic Colletotrichum spp.
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DOI：
10.1094/mpmi-20-10-1308
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发表时间：
2007-10-01
影响因子：
3.5
通讯作者：
Wei, Yangdou
中科院分区：
文献类型：
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作者：
Liu, Guosheng;Kennedy, Regan;Wei, Yangdou
炭疽菌属是一种重要的农业模式病原菌，可用于拟南芥的防御研究。在拟南芥上筛选新的致病性炭疽菌分离物的过程中，我们发现离体叶片和附着叶片的防御反应存在显著差异。一个近适应的隔离Colletotrichum linicola A1可以启动一个典型的感染，只有在分离，但不重视，拟南芥叶片。值得注意的是，抗性基因样焦点RCH 1介导的完整植物的抗性也受到损害，在离体叶片的攻击过程中与毒性参考分离C higginsianum。离体叶片和完整的植物检测之间的症状发展的差异进一步证实了防御缺陷突变体接种C higginsianum，其中最大的不一致发生在乙烯不敏感的突变体。在完整的拟南芥植物中，水杨酸和乙烯依赖的途径所需的抗C higginsianum，并与诱导表达的病程相关基因PR1和PDF1.2。相反，离体叶片的疾病症状发展似乎与这些防御途径无关，并且与衰老更密切相关：通过协调基因表达分析和疾病症状发展以及化学和遗传模拟衰老证实了这一观察结果。
The agriculturally important genus Colletotrichum is an emerging model pathogen for studying defense in Arabidopsis. During the process of screening for novel pathogenic Colletotrichum isolates on Arabidopsis, we found significant differences in defense responses between detached and attached leaf assays. A near-adapted isolate Colletotrichum linicola A1 could launch a typical infection only on detached, but not attached, Arabidopsis leaves. Remarkably, resistance gene-like focus RCH1-mediated resistance in intact plants also was compromised in detached leaves during the attacks with the virulent reference isolate C higginsianum. The differences in symptom development between the detached leaf and intact plant assays were further confirmed on defense-defective mutants following inoculation with C higginsianum, where the greatest inconsistency occurred on ethylene-insensitive mutants. In intact Arabidopsis plants, both the salicylic acid- and ethylene-dependent pathways were required for resistance to C higginsianum and were associated with induced expression of pathogenesis-related genes PR1 and PDF1.2. In contrast, disease symptom development in detached leaves appeared to be uncoupled from these defense pathways and more closely associated with senescence: an observation substantiated by coordinated gene expression analysis and disease symptom development, and chemically and genetically mimicking senescence.