The Arabidopsis miR396 mediates pathogen-associated molecular pattern-triggered immune responses against fungal pathogens.
The Arabidopsis miR396 mediates pathogen-associated molecular pattern-triggered immune responses against fungal pathogens.
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DOI：
10.1038/srep44898
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发表时间：
2017-03-23
影响因子：
4.6
通讯作者：
San Segundo B
中科院分区：
文献类型：
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作者：
Soto-Suárez M;Baldrich P;Weigel D;Rubio-Somoza I;San Segundo B
在植物发育过程中，microRNAs(MiRNAs)在基因表达调控中起着关键作用。虽然相当一部分植物miRNAs已被证明对病原体侵染有反应，但它们在抗病中的作用仍然很大程度上尚不清楚，特别是在真菌感染期间。在这项研究中，我们使用人工miRNA靶标模拟物(MIM系)筛选了miRNA活性降低的拟南芥品系(MIM系)，以研究它们对真菌病原体的反应。MiR396(MIM396植物)的活性降低被发现对坏死性和半生物营养性真菌病原体具有广泛的抗性。在真菌感染过程中，miR396的水平逐渐下降，从而使其GRF(生长调节因子)转录因子目标基因能够触发宿主重新编程。MIM396植物对病原菌的抗性建立在病原菌侵染过程中与启动事件一致的防御反应的过度激活基础上。值得注意的是，在没有病原体挑战的情况下，低水平的miR396不会转化为发育缺陷。我们的发现支持miR396在调节植物免疫方面的作用，并拓宽了我们对维持防御启动的分子参与者和过程的了解。MiR396在没有生长成本的情况下调节先天免疫，这也表明微调miR396水平是预防病原体感染的有效生物技术手段。
MicroRNAs (miRNAs) play a pivotal role in regulating gene expression during plant development. Although a substantial fraction of plant miRNAs has proven responsive to pathogen infection, their role in disease resistance remains largely unknown, especially during fungal infections. In this study, we screened Arabidopsis thaliana lines in which miRNA activity has been reduced using artificial miRNA target mimics (MIM lines) for their response to fungal pathogens. Reduced activity of miR396 (MIM396 plants) was found to confer broad resistance to necrotrophic and hemibiotrophic fungal pathogens. MiR396 levels gradually decreased during fungal infection, thus, enabling its GRF (GROWTH-REGULATING FACTOR) transcription factor target genes to trigger host reprogramming. Pathogen resistance in MIM396 plants is based on a superactivation of defense responses consistent with a priming event during pathogen infection. Notably, low levels of miR396 are not translated in developmental defects in absence of pathogen challenge. Our findings support a role of miR396 in regulating plant immunity, and broaden our knowledge about the molecular players and processes that sustain defense priming. That miR396 modulates innate immunity without growth costs also suggests fine-tuning of miR396 levels as an effective biotechnological means for protection against pathogen infection.