PDF(Pubmed)
Abstract：
The establishment of host-microbe interactions requires molecular communication between both partners, which may involve the mutual transfer of noncoding small RNAs. Previous evidence suggests that this is also true for powdery mildew disease in barley, which is caused by the fungal pathogen Blumeria hordei. However, previous studies lacked spatial resolution regarding the accumulation of small RNAs upon host infection by B. hordei. Here, we analysed site-specific small RNA repertoires in the context of the barley-B. hordei interaction. To this end, we dissected infected leaves into separate fractions representing different sites that are key to the pathogenic process: epiphytic fungal mycelium, infected plant epidermis, isolated haustoria, a vesicle-enriched fraction from infected epidermis, and extracellular vesicles. Unexpectedly, we discovered enrichment of specific 31-33-base 5\'-terminal fragments of barley 5.8S ribosomal RNA in extracellular vesicles and infected epidermis, as well as particular B. hordei transfer RNA fragments in haustoria. We describe canonical small RNAs from both the plant host and the fungal pathogen that may confer cross-kingdom RNA interference activity. Interestingly, we found first evidence of phased small interfering RNAs in B. hordei, a feature usually attributed to plants, which may be associated with the posttranscriptional control of fungal coding genes, pseudogenes, and transposable elements. Our data suggest a key and possibly site-specific role for cross-kingdom RNA interference and noncoding RNA fragments in the host-pathogen communication between B. hordei and its host barley.
摘要：
宿主-微生物相互作用的建立需要两个伙伴之间的分子交流，这可能涉及非编码小RNA的相互转移。以前的证据表明，大麦白粉病也是如此，这是由真菌病原体Blumeriahordei引起的。然而,以前的研究缺乏关于小RNA在宿主感染B.hordei后积累的空间分辨率。这里,我们在大麦B的背景下分析了位点特异性小RNA库。hordei互动。为此,我们将受感染的叶子解剖成代表致病过程关键的不同部位的单独部分：附生真菌菌丝体，受感染的植物表皮，孤立的豪斯，来自受感染表皮的富含囊泡的部分，和细胞外囊泡。出乎意料的是,我们在细胞外囊泡和感染的表皮中发现大麦5.8S核糖体RNA的特定31-33碱基5'末端片段的富集，以及haustoria中特定的B.hordei转移RNA片段。我们描述了来自植物宿主和真菌病原体的典型小RNA，它们可能赋予跨王国RNA干扰活性。有趣的是,我们在B.hordei中发现了阶段性小干扰RNA的第一个证据，通常归因于植物的特征，这可能与真菌编码基因的转录后控制有关，假基因，和转座元素。我们的数据表明，跨王国RNA干扰和非编码RNA片段在大麦芽孢杆菌与其宿主大麦之间的宿主-病原体通讯中具有关键且可能具有位点特异性的作用。
