Wheat ( L.), a staple crop cultivated across an estimated 215 million hectares worldwide, encounters significant yield reductions due to the leaf rust disease, instigated by the fungus (). Control strategies for this pathogen are limited. Research on wheat-leaf rust interaction in the past few years has mainly focused on characterizing and modulating the performance of resistance () and other defense genes of the host plant, but rarely targeted to decipher the network of molecular strategies employed by the pathogen except secretome analysis. In wheat plants, pathogen may induce a greater diversity of small RNAs (sRNAs) to manipulate the host's gene expression and suppress defense responses. In the present study, microRNA-like-RNAs (milRNAs) were screened and identified from sRNA libraries prepared from leaf rust pathogen-infected leaves of wheat near isogenic lines (NILs). Pathogenesis engendering target genes were validated through degradome libraries. Our study indicates that milRNAs enter the host system to suppress its immunity and promote symbiosis-like association to maintain a longer virulence span. Through RT‒qPCR expression analysis, it was suggested that milRNAs create an environment to enhance symbiosis via cross-kingdom silencing of host disease resistance gene encoding proteins. We found that seven out of eight milRNAs effectively regulate pathogenesis-related genes and repressed the disease-resistance genes in host wheat. Functional annotation of target genes of reveals regulation of vesicle synthesis, transport, and fusion, which represents cross-kingdom vesicle-mediated export of milRNAs. Our results also manifest an integrative view of how virulence-associated milRNAs endeavor to stamp out PTI (PAMP-triggered immunity) and ETI (Effector-triggered immunity) to increase susceptibility of the host. This study epitomizes one of the tactics developed by employing milRNAs in regulating virulence during leaf rust infection and will usher to design strategies to manage pathogenesis to protect wheat immunity against leaf rust disease.

中文翻译：

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通过高通量测序数据揭示 microRNA 样 RNA 在增强小麦锈病致病性中的作用

小麦 (L.) 是一种主要农作物，全球种植面积估计为 2.15 亿公顷，由于真菌引发的叶锈病，小麦 (L.) 的产量大幅下降 ()。这种病原体的控制策略是有限的。过去几年关于小麦叶锈病相互作用的研究主要集中在表征和调节寄主植物的抗性（）和其他防御基因的性能，但很少针对破译除分泌组之外的病原体所采用的分子策略网络。分析。在小麦植物中，病原体可能会诱导更多样化的小 RNA (sRNA) 来操纵宿主的基因表达并抑制防御反应。在本研究中，从近等基因系（NIL）小麦受叶锈病病原体感染的叶子制备的sRNA文库中筛选和鉴定了类似microRNA（milRNA）。通过降解组文库验证了产生靶基因的发病机制。我们的研究表明，milRNA 进入宿主系统以抑制其免疫并促进共生样关联，以维持更长的毒力跨度。通过 RT-qPCR 表达分析，表明 milRNA 通过跨界沉默宿主抗病基因编码蛋白来创造增强共生的环境。我们发现，八分之七的 milRNA 有效调节发病相关基因并抑制宿主小麦的抗病基因。靶基因的功能注释揭示了囊泡合成、运输和融合的调节，这代表了跨界囊泡介导的 milRNA 输出。我们的结果还体现了毒力相关 milRNA 如何努力消除 PTI（PAMP 触发免疫）和 ETI（效应器触发免疫）以增加宿主易感性的综合观点。这项研究集中体现了利用 milRNA 调节叶锈病感染期间毒力的策略之一，并将引导设计策略来管理发病机制，以保护小麦对叶锈病的免疫力。