日本国家基础生物研究所Makoto Hayashi、Takashi Soyano等研究人员合作，在百脉根中发现了一个促进侧根发育与根瘤共生的基因。相关论文于2019年11月22日发表于国际学术期刊《科学》。

研究人员发现NIN（NODULE INCEPTION）是百脉根（Lotus japonicus）中在结瘤过程中启动皮层细胞分裂所必需的转录因子，并参与调控ASL18/LBD16a（ASYMMETRIC LEAVES 2-LIKE 18/LATERAL ORGAN BOUNDARIES DOMAIN 16a）基因。非豆科植物中ASL18/LBD16a的直系同源物是侧向根发育所必需的。ASL18a和NF-Y（CCAAT box–binding protein Nuclear Factor-Y）亚基的共表达（这两个基因被MIN直接调控），一定程度上减少了百脉根突变体的结节缺陷表型。

这些结果表明，ASL18a和NF-Y共同调节结节器官的发生。因此，在NIN的下游存在一条侧根发育途径来促进结节共生。

据介绍，豆类与固氮根瘤菌共生时会形成根瘤。根瘤菌引起分化的皮层细胞分裂成根瘤原基，以容纳细菌共生体。

附：英文原文

Title: A shared gene drives lateral root development and root nodule symbiosis pathways in Lotus

Author: Takashi Soyano, Yoshikazu Shimoda, Masayoshi Kawaguchi, Makoto Hayashi

Issue&Volume: 2019/11/22

Abstract: Legumes develop root nodules in symbiosis with nitrogen-fixing rhizobial bacteria. Rhizobia evoke cell division of differentiated cortical cells into root nodule primordia for accommodating bacterial symbionts. In this study, we show that NODULE INCEPTION (NIN), a transcription factor in Lotus japonicus that is essential for initiating cortical cell divisions during nodulation, regulates the gene ASYMMETRIC LEAVES 2-LIKE18/LATERAL ORGAN BOUNDARIES DOMAIN16a (ASL18/LBD16a). Orthologs of ASL18/LBD16a in nonlegume plants are required for lateral root development. Coexpression of ASL18a and the CCAAT box–binding protein Nuclear Factor-Y (NF-Y) subunits, which are also directly targeted by NIN, partially suppressed the nodulation-defective phenotype of L. japonicusdaphne mutants, in which cortical expression of NIN was attenuated. Our results demonstrate that ASL18a and NF-Y together regulate nodule organogenesis. Thus, a lateral root developmental pathway is incorporated downstream of NIN to drive nodule symbiosis.

DOI: 10.1126/science.aax2153

Source: https://science.sciencemag.org/content/366/6468/1021