Developmental regulated mechanisms affect the ability of a fungal pathogen to infect and colonize tobacco leaves
Developmental regulated mechanisms affect the ability of a fungal pathogen to infect and colonize tobacco leaves
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DOI：
10.1046/j.1365-313x.1999.00587.x
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发表时间：
1999-10-01
期刊：
影响因子：
7.2
通讯作者：
Galiana, E
中科院分区：
文献类型：
--
作者：
Hugot, K;Aimé, S;Galiana, E
在烟草发育过程中，观察到对真菌病原菌感染从易感到抗性的过渡状态。当植物开始开花时，叶片获得对寄生疫霉的抗性。产生耐药性的能力并不意味着病原体诱导的防御反应，如发生全身性获得性耐药性（SAR）。在整个开花生长过程中，真菌的建立受到两个层次的限制。第一个层面是控制感染效果。使用不积累水杨酸的NahG植株，我们证明了这种控制不需要水杨酸积累。基于体外萌发试验，烟草叶片的细胞间液（IFs）对真菌游动孢子细胞具有细胞毒活性。其积累与花期侵染效果的控制有关。这种活性的表达似乎构成了一种发育调节机制，抑制真菌病原体安装的早期步骤。真菌生长控制的第二个层面是真菌菌丝扩张的限制。与感染起始相反，真菌菌丝的传播似乎受到SAR诱导的类似机制的限制，因为它被水杨酸积累的需要和相关的PR1蛋白的外胞体积累所证明。这些结果为在开花生长过程中激活一组至少两种调节途径提供了证据。这种激活导致通过影响真菌感染和定植植物组织的能力来控制真菌发育的机制的诱导。
During tobacco development, a transition state from susceptibility to resistance to fungal pathogen infection is observed. Leaves acquire resistance to Phytophthora parasistica when the plant becomes committed to flowering. The ability to develop resistance does not imply pathogen-induced defence responses as for the onset of systemic acquired resistance (SAR). Throughout flowering growth, fungal establishment is restrained at two levels. The first level is the control of infection effectiveness. Using the salicylic acid non-accumulating NahG plants, we demonstrate that this control does not require salicylic acid accumulation. The intercellular fluids (IFs) from tobacco leaves committed to flowering exhibit a cytotoxic activity on fungal zoospore cells based on in vitro germination assays. Its accumulation is correlated to the control of infection effectiveness that occurs during flowering growth. The expression of this activity appears to constitute a developmental regulated mechanism that inhibits early steps of fungal pathogen installation. A second level of fungal growth control is the restriction of fungal hyphae expansion. In contrast to infection initiation, fungal hyphae spreading appears to be restricted by similar mechanisms induced during SAR as it is attested by the requirement of salicylic acid accumulation and by the correlating apoplastic accumulation of PR1 proteins. These results provide evidence for the activation of a set of at least two regulatory pathways during flowering growth. This activation leads to the induction of mechanisms which control fungal development by affecting the ability of the fungus to both infect and colonise plant tissues.