Wei Feng, Liu Yuan, Zhou Donglai, Zhao Wenlong, Chen Zhennan, Chen Dason, Li Youguo, Zhang Xue-Xian
State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
School of Natural Sciences, Massey University at Albany, Auckland 0745, New Zealand.
Mol Plant Microbe Interact. 2022 Oct;35(10):893-905. doi: 10.1094/MPMI-03-22-0054-R. Epub 2022 Sep 27.
Legumes in the inverted repeat-lacking clade (IRLC) each produce a unique set of nodule-specific cysteine-rich (NCR) peptides, which act in concert to determine the terminal differentiation of nitrogen-fixing bacteroid. IRLC legumes differ greatly in their numbers of NCR and sequence diversity. This raises the significant question how bacteroid differentiation is collectively controlled by the specific NCR repertoire of an IRLC legume. is an IRLC legume that forms indeterminate nodules with its microsymbiont 7653R. Here, we performed transcriptome analysis of root and nodule samples at 3, 7, 14, 28 days postinoculation with 7653R and its isogenic ∆ mutant. BacA is a broad-specificity peptide transporter required for the host-derived NCRs to target rhizobial cells. A total of 167 NCRs were identified in the RNA transcripts. Comparative sequence and electrochemical analysis revealed that NCRs (AsNCRs) are dominated by a unique cationic group (termed subgroup C), whose mature portion is relatively long (>60 amino acids) and phylogenetically distinct and possessing six highly conserved cysteine residues. Subsequent functional characterization showed that a 7653R variant harboring AsNCR083 (a representative of subgroup C AsNCR) displayed significant growth inhibition in laboratory media and formed ineffective white nodules on with irregular symbiosomes. Finally, bacterial two-hybrid analysis led to the identification of GroEL1 and GroEL3 as the molecular targets of AsNCR067 and AsNCR076. Together, our data contribute to a systematic understanding of the NCR repertoire associated with the and symbiosis. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
缺乏反向重复序列分支（IRLC）的豆科植物各自产生一组独特的根瘤特异性富含半胱氨酸（NCR）的肽，这些肽共同作用以决定固氮类菌体的终末分化。IRLC豆科植物在NCR数量和序列多样性上差异很大。这就引出了一个重要问题，即IRLC豆科植物特定的NCR库如何共同控制类菌体分化。是一种IRLC豆科植物，它与其微共生体7653R形成不定根瘤。在这里，我们对接种7653R及其同基因∆突变体后3、7、14、28天的根和根瘤样本进行了转录组分析。BacA是宿主来源的NCR靶向根瘤菌细胞所需的一种广谱肽转运蛋白。在RNA转录本中总共鉴定出167个NCR。比较序列和电化学分析表明，NCR（AsNCRs）以一个独特的阳离子基团（称为C亚组）为主，其成熟部分相对较长（>60个氨基酸），在系统发育上不同，并且具有六个高度保守的半胱氨酸残基。随后的功能表征表明，携带AsNCR083（C亚组AsNCR的代表）的7653R变体在实验室培养基中表现出显著的生长抑制，并在上形成无效的白色根瘤，共生体不规则。最后，细菌双杂交分析确定GroEL1和GroEL3为AsNCR067和AsNCR076的分子靶点。总之，我们的数据有助于系统地了解与和共生相关的NCR库。[公式：见正文] 版权所有©2022作者。这是一篇根据知识共享署名 - 非商业性使用 - 禁止演绎4.0国际许可协议分发的开放获取文章。
