Laboratory of Molecular Biology, Wageningen University & Research, Wageningen, 6708 PB, the Netherlands.
Laboratory of Biochemistry, Wageningen University & Research, Wageningen, 6708 WE, the Netherlands.
New Phytol. 2021 May;230(3):1142-1155. doi: 10.1111/nph.17236. Epub 2021 Feb 28.
Arguably, symbiotic arbuscular mycorrhizal (AM) fungi have the broadest host range of all fungi, being able to intracellularly colonise root cells in the vast majority of all land plants. This raises the question how AM fungi effectively deal with the immune systems of such a widely diverse range of plants. Here, we studied the role of a nuclear-localisation signal-containing effector from Rhizophagus irregularis, called Nuclear Localised Effector1 (RiNLE1), that is highly and specifically expressed in arbuscules. We showed that RiNLE1 is able to translocate to the host nucleus where it interacts with the plant core nucleosome protein histone 2B (H2B). RiNLE1 is able to impair the mono-ubiquitination of H2B, which results in the suppression of defence-related gene expression and enhanced colonisation levels. This study highlights a novel mechanism by which AM fungi can effectively control plant epigenetic modifications through direct interaction with a core nucleosome component. Homologues of RiNLE1 are found in a range of fungi that establish intimate interactions with plants, suggesting that this type of effector may be more widely recruited to manipulate host defence responses.
可以说，共生丛枝菌根（AM）真菌拥有最广泛的宿主范围，能够在绝大多数陆生植物的根细胞内进行细胞内定殖。这就提出了一个问题，即 AM 真菌如何有效地应对如此广泛多样的植物的免疫系统。在这里，我们研究了 Rhizophagus irregularis 中一种含有核定位信号的效应物，称为核定位效应物 1（RiNLE1），它在丛枝中高度且特异性表达。我们表明，RiNLE1 能够易位到宿主核内，在那里它与植物核心核小体蛋白组蛋白 2B（H2B）相互作用。RiNLE1 能够抑制 H2B 的单泛素化，从而抑制防御相关基因的表达并增强定殖水平。这项研究强调了 AM 真菌通过与核心核小体成分的直接相互作用来有效控制植物表观遗传修饰的新机制。RiNLE1 的同源物存在于与植物建立密切相互作用的一系列真菌中，这表明这种类型的效应物可能更广泛地被招募来操纵宿主防御反应。
