1 Centre for Research in Agricultural Genomics (CRAG) CSIC, IRTA, UAB, UB. Edifici CRAG. Carrer de la Vall Moronta. Campus UAB, Bellaterra (Cerdanyola del Vallés), 08193 Barcelona, Spain.
2 Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany; and.
Mol Plant Microbe Interact. 2018 Feb;31(2):249-259. doi: 10.1094/MPMI-05-17-0108-R. Epub 2017 Dec 6.
MicroRNAs (miRNAs) are 21- to 24-nucleotide short noncoding RNAs that trigger gene silencing in eukaryotes. In plants, miRNAs play a crucial role in a wide range of developmental processes and adaptive responses to abiotic and biotic stresses. In this work, we investigated the role of miR773 in modulating resistance to infection by fungal pathogens in Arabidopsis thaliana. Interference with miR773 activity by target mimics (in MIM773 plants) and concomitant upregulation of the miR773 target gene METHYLTRANSFERASE 2 (MET2) increased resistance to infection by necrotrophic (Plectosphaerrella cucumerina) and hemibiotrophic (Fusarium oxysporum, Colletototrichum higginianum) fungal pathogens. By contrast, both MIR773 overexpression and MET2 silencing enhanced susceptibility to pathogen infection. Upon pathogen challenge, MIM773 plants accumulated higher levels of callose and reactive oxygen species than wild-type plants. Stronger induction of defense-gene expression was also observed in MIM773 plants in response to fungal infection. Expression analysis revealed an important reduction in miR773 accumulation in rosette leaves of plants upon elicitor perception and pathogen infection. Taken together, our results show not only that miR773 mediates pathogen-associated molecular pattern-triggered immunity but also demonstrate that suppression of miR773 activity is an effective approach to improve disease resistance in Arabidopsis plants.
MicroRNAs (miRNAs) 是 21 到 24 个核苷酸的短非编码 RNA，可在真核生物中引发基因沉默。在植物中，miRNAs 在广泛的发育过程和对非生物和生物胁迫的适应性反应中发挥着至关重要的作用。在这项工作中，我们研究了 miR773 在调节拟南芥对真菌病原体感染的抗性中的作用。通过靶标模拟物（在 MIM773 植物中）干扰 miR773 的活性，以及 miR773 靶基因 METHYLTRANSFERASE 2（MET2）的伴随上调，增加了对坏死型（Plectosphaerrella cucumerina）和半生物型（Fusarium oxysporum、Colletototrichum higginianum）真菌病原体的感染抗性。相比之下，MIR773 的过表达和 MET2 的沉默都增强了对病原体感染的敏感性。在病原体攻击下，MIM773 植物比野生型植物积累了更高水平的胼胝质和活性氧。在 MIM773 植物中，还观察到对真菌感染的防御基因表达的强烈诱导。表达分析显示，在感应激发子和病原体感染后，miR773 在拟南芥的莲座叶中的积累量显著减少。综上所述，我们的结果不仅表明 miR773 介导了病原体相关分子模式触发的免疫，还证明了抑制 miR773 的活性是提高拟南芥植物抗病性的有效方法。
