Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW 2753, Australia.
NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, NSW 2568, Australia.
Proc Natl Acad Sci U S A. 2022 Jan 18;119(3). doi: 10.1073/pnas.2103527119.
Small RNAs (sRNAs) are known to regulate pathogenic plant-microbe interactions. Emerging evidence from the study of these model systems suggests that microRNAs (miRNAs) can be translocated between microbes and plants to facilitate symbiosis. The roles of sRNAs in mutualistic mycorrhizal fungal interactions, however, are largely unknown. In this study, we characterized miRNAs encoded by the ectomycorrhizal fungus and investigated their expression during mutualistic interaction with Using sRNA sequencing data and in situ miRNA detection, a novel fungal miRNA, , was found to be transported into roots after interaction with Further characterization experiments demonstrate that inhibition of negatively impacts the maintenance of mycorrhizal roots in , while supplementation of led to deeper integration of the fungus into plant tissues. Target prediction and experimental testing suggest that may target the host NB-ARC domain containing transcripts, suggesting a potential role for this miRNA in subverting host signaling to stabilize the symbiotic interaction. Altogether, we provide evidence of previously undescribed cross-kingdom sRNA transfer from ectomycorrhizal fungi to plant roots, shedding light onto the involvement of miRNAs during the developmental process of mutualistic symbioses.
小 RNA（sRNA）被认为可以调节病原植物-微生物的相互作用。从这些模型系统的研究中获得的新证据表明，microRNAs（miRNAs）可以在微生物和植物之间转移，以促进共生。然而，sRNA 在互惠共生菌根真菌相互作用中的作用在很大程度上是未知的。在这项研究中，我们对共生菌根真菌中的 miRNA 进行了表征，并研究了它们在与 共生过程中的表达。通过 sRNA 测序数据和原位 miRNA 检测，发现一种新型的真菌 miRNA， ，在与 相互作用后被运输到 根中。进一步的特征分析实验表明，抑制 会对 中菌根根的维持产生负面影响，而 的补充则导致真菌更深地整合到植物组织中。靶标预测和实验测试表明， 可能靶向宿主含有 NB-ARC 结构域的转录本，这表明该 miRNA 在颠覆宿主信号以稳定共生相互作用方面可能发挥作用。总之，我们提供了从外生菌根真菌到植物根的跨领域 sRNA 转移的先前未描述的证据，揭示了 miRNA 在互惠共生发育过程中的参与。
