The Fusarium mycotoxin deoxynivalenol elicits hydrogen peroxide production, programmed cell death and defence responses in wheat
The Fusarium mycotoxin deoxynivalenol elicits hydrogen peroxide production, programmed cell death and defence responses in wheat
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DOI：
10.1111/j.1364-3703.2008.00475.x
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发表时间：
2008-07-01
影响因子：
4.9
通讯作者：
Kazan, Kemal
中科院分区：
文献类型：
--
作者：
Desmond, Olivia J.;Manners, John M.;Kazan, Kemal
镰刀菌种类侵染世界范围内的粮食作物，引起小麦赤霉病和冠腐病等重要病害。镰刀菌会降低产量，一些物种在感染期间还会产生脱氧雪腐镰刀菌烯醇(DON)等毛霉烯类真菌毒素。这些毒素在小麦发病机制中发挥作用，如果存在于人或动物食用的谷物中，则会对健康产生严重影响。本文研究了小麦组织对DON的响应。DON诱导小麦叶片在6h内产生过氧化氢，随后在24h内细胞死亡，并伴有DNA梯状条带，这是细胞程序性死亡的标志。实时荧光定量聚合酶链式反应分析表明，DON以浓度依赖的方式快速诱导了一些防御基因的转录。DON和抗氧化剂抗坏血酸的共同处理减少了这些反应，这表明它们的诱导可能至少部分是由活性氧物种(ROS)介导的，ROS通常被认为是植物中的信号分子。小麦的防御基因在接种DON产生的真菌菌株的小麦茎中比接种DON不产生的突变体的小麦茎中高表达，但仅在感染的后期。综上所述，这一结果与小麦侵染过程中DON的产生诱导ROS的模型是一致的，该模型一方面可能刺激寄主细胞程序性死亡，促进坏死型真菌的生长，另一方面，ROS可能有助于诱导抗菌宿主防御。
Fusarium species infect cereal crops worldwide and cause the important diseases Fusarium head blight and crown rot in wheat. Fusarium pathogens reduce yield and some species also produce trichothecene mycotoxins, such as deoxynivalenol (DON), during infection. These toxins play roles in pathogenesis on wheat and have serious health effects if present in grain consumed by humans or animals. In the present study, the response of wheat tissue to DON has been investigated. Infusion of wheat leaves with DON induced hydrogen peroxide production within 6 h followed by cell death within 24 h that was accompanied by DNA laddering, a hallmark of programmed cell death. In addition, real-time PCR analysis revealed that DON treatment rapidly induced transcription of a number of defence genes in a concentration-dependent manner. Co-treatment with DON and the antioxidant ascorbic acid reduced these responses, suggesting their induction may be at least partially mediated by reactive oxygen species (ROS), commonly known to be signalling molecules in plants. Wheat defence genes were more highly expressed in wheat stems inoculated with a DON-producing fungal strain than those inoculated with a DON-non-producing mutant, but only at a late stage of infection. Taken together, the results are consistent with a model in which DON production during infection of wheat induces ROS, which on the one hand may stimulate programmed host cell death assisting necrotrophic fungal growth, whereas, on the other hand, the ROS may contribute to the induction of antimicrobial host defences.