Osa-miR7695 enhances transcriptional priming in defense responses against the rice blast fungus
Osa-miR7695 enhances transcriptional priming in defense responses against the rice blast fungus
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DOI：
10.1186/s12870-019-2156-5
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发表时间：
2019-12-18
影响因子：
5.3
通讯作者：
Campo, Sonia
中科院分区：
文献类型：
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作者：
Sanchez-Sanuy, Ferran;Peris-Peris, Cristina;Campo, Sonia
背景：MicroRNAs （miRNAs）是一种小的非编码rna，在真核生物的转录后水平调控基因表达。在水稻中，MIR7695的表达受稻瘟病菌Magnaporthe oryzae感染的调控，随后下调天然抗性相关巨噬细胞蛋白6 （OsNramp6）的选择性剪接转录物。NRAMP6在水稻中起铁转运蛋白的作用。结果：水稻在高铁条件下表现出抗稻瘟病性，说明铁是控制稻瘟病抗性的因素之一。在病原菌侵染过程中，铁元素在稻稻瘟病菌附着菌附近、病原菌进入位点以及水稻叶片侵染区周围的细胞中积累。激活标记的MIR7695水稻植株（MIR7695- ac）表现出增强的铁积累和对M. oryzae感染的抗性。RNA-seq分析显示，MIR7695-Ac植株的稻瘟病抗性与防御相关基因（包括致病相关基因和二萜类生物合成基因）的强诱导有关。病原菌感染时，MIR7695-Ac植物抗毒素水平高于野生型植物。在高铁环境下生长的野生型水稻中，早期植物抗毒素生物合成基因OsCPS2和OsCPS4也高度上调。结论：我们的数据支持miR7695在调节水稻免疫中的积极作用，进一步支持水稻防御和铁信号传导之间的联系。这些发现为更好地理解miR7695参与的水稻免疫调控机制提供了基础，为开发提高水稻稻瘟病抗性的策略提供了巨大的潜力。
Background: MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the post-transcriptional level in eukaryotes. In rice, MIR7695 expression is regulated by infection with the rice blast fungus Magnaporthe oryzae with subsequent down-regulation of an alternatively spliced transcript of natural resistance-associated macrophage protein 6 (OsNramp6). NRAMP6 functions as an iron transporter in rice.Results: Rice plants grown under high iron supply showed blast resistance, which supports that iron is a factor in controlling blast resistance. During pathogen infection, iron accumulated in the vicinity of M. oryzae appressoria, the sites of pathogen entry, and in cells surrounding infected regions of the rice leaf. Activation-tagged MIR7695 rice plants (MIR7695-Ac) exhibited enhanced iron accumulation and resistance to M. oryzae infection. RNA-seq analysis revealed that blast resistance in MIR7695-Ac plants was associated with strong induction of defense-related genes, including pathogenesis-related and diterpenoid biosynthetic genes. Levels of phytoalexins during pathogen infection were higher in MIR7695-Ac than wild-type plants. Early phytoalexin biosynthetic genes, OsCPS2 and OsCPS4, were also highly upregulated in wild-type rice plants grown under high iron supply.Conclusions: Our data support a positive role of miR7695 in regulating rice immunity that further underpin links between defense and iron signaling in rice. These findings provides a basis to better understand regulatory mechanisms involved in rice immunity in which miR7695 participates which has a great potential for the development of strategies to improve blast resistance in rice.