Key message

Rice MERISTEM ACTIVITYLESS (MAL), a RING-H2 finger domain (RFD)-containing gene, regulates meristem cell viability after the initiation of root primordia mediated by cytokinin signaling.

Abstract

Genes in the RING-H2 finger domain (RFD) family play various roles during plant development and in biotic/abiotic stress responses. Rice gene MERISTEM ACTIVITYLESS (MAL), being contained in the RING-H2 finger domain (RFD), is characterized by a transmembrane domain at the N-terminal and a C3H2C3 zinc finger domain at the C-terminal. To elucidate the physiological and molecular functions of MAL, we generated MAL knockdown transgenic plants by RNA interference. MAL RNA-interfered (MRi) transgenic plants exhibited a phenotype with shorter crown root length and lower crown root number, accompanied by a lower cell division rate. The low division rate was observed in the root meristem exactly where MAL was expressed. Furthermore, transcriptome data revealed that cell wall macromolecule metabolism-related genes and redox-related genes were enriched in MAL RNAi lines. Most of these differentially expressed genes (DEGs) were induced by exogenous cytokinin. Hence, we conclude that MAL, as a novel regulatory factor, plays a major role in maintaining cell viability in the meristem after the initiation of root primordial formation, mediated by cytokinin signaling and reactive oxygen species (ROS).

中文翻译：

---

MERISTEM ACTIVITYLESS (MAL) 通过维持水稻的分生组织大小参与根系发育。

关键信息

水稻分生组织活性 (MAL)是一种含有 RING-H2 指结构域 (RFD) 的基因，在细胞分裂素信号介导的根原基启动后调节分生组织细胞的活力。

抽象的

RING-H2 指结构域 (RFD) 家族中的基因在植物发育和生物/非生物胁迫反应中发挥着不同的作用。水稻基因M ERISTEM A CTIVITY L ESS ( MAL ) 包含在RING-H2 指结构域(RFD) 中，其特征在于N 端的跨膜结构域和C 端的C3H2C3 锌指结构域。为了阐明MAL的生理和分子功能，我们通过 RNA 干扰产生了MAL敲低转基因植物。MAL RNA 干扰 ( MRi) 转基因植物表现出冠根长度较短、冠根数较低的表型，伴随着较低的细胞分裂率。在表达MAL的根分生组织中观察到低分裂率。此外，转录组数据显示细胞壁大分子代谢相关基因和氧化还原相关基因在MAL RNAi 系中富集。大多数这些差异表达基因（DEG）是由外源性细胞分裂素诱导的。因此，我们得出结论，MAL作为一种新的调节因子，在根原基形成开始后在维持分生组织中的细胞活力方面起主要作用，由细胞分裂素信号传导和活性氧 (ROS) 介导。