美国普渡大学马渐新（Jianxin Ma）小组在研究中取得进展。他们发现，根瘤菌tRNA来源的小RNA是调节植物结瘤的信号分子。该研究2019年8月30日发表于《科学》。

研究人员介绍，豆科植物的根瘤菌感染和根瘤形成需要识别细菌及其宿主产生的信号分子。研究人员发现根瘤菌转运RNA（tRNA）衍生的小RNA片段（tRFs）是调节宿主结瘤的信号分子。研究人员确认了3个根瘤菌tRF家族通过劫持涉及ARGONAUTE 1的宿主RNA干扰机制来调节与结节起始和发育相关的宿主基因。使用短串联靶标模拟物去沉默单独的tRF或通过过表达其靶标能够抑制根卷曲和结节形成，而用与各自tRF相同的人工小RNA抑制这些靶标或用CRISPR-Cas9突变这些靶标能够促进结瘤。

因此，这些研究结果揭示了细菌小RNA介导的原核生物-真核生物相互作用机制，可能为提高豆科植物的结瘤效率提供途径。

附：英文原文

Title: Rhizobial tRNA-derived small RNAs are signal molecules regulating plant nodulation

Author: Bo Ren, Xutong Wang, Jingbo Duan, Jianxin Ma

Issue&Volume: Volume 365 Issue 6456, 2019/08/30

Abstract: Rhizobial infection and root nodule formation in legumes require recognition of signal molecules produced by the bacteria and their hosts. Here, we show that rhizobial transfer RNA (tRNA)-derived small RNA fragments (tRFs) are signal molecules that modulate host nodulation. Three families of rhizobial tRFs were confirmed to regulate host genes associated with nodule initiation and development through hijacking the host RNA-interference machinery that involves ARGONAUTE 1. Silencing individual tRFs with the use of short tandem target mimics or by overexpressing their targets represses root hair curling and nodule formation, whereas repressing these targets with artificial microRNAs identical to the respective tRFs or mutating these targets with CRISPR-Cas9 promotes nodulation. Our findings thus uncover a bacterial small RNA–mediated mechanism for prokaryote-eukaryote interaction and may pave the way for enhancing nodulation efficiency in legumes.

DOI: 10.1126/science.aav8907

Source: https://science.sciencemag.org/content/365/6456/919