HY5 inhibits in vitro shoot stem cell niches initiation via directly repressing pluripotency and cytokinin pathways

第一作者：Xuehuan Dai

第一单位：山东大学

第一通讯：Fengning Xiang

 Abstarct 

背景回顾：The efficiency of plant regeneration from explants is influenced by phytohormones and environmental conditions. 

植物由外植体的再生效率受到植物激素和外界环境条件的影响。

提出问题：Light has a particularly marked effect on in vitro shoot regeneration, and some light signaling factors are involved in shoot regeneration, while the underlying molecular mechanism remains elusive. 

光对于体外芽再生具有非常重要的影响，并且某些光信号因子会参与到植物的芽再生过程中，但是潜在的分子机制却仍不清晰。

主要研究：Here, ELONGATED HYPOCOTYL5 (HY5), as the key transcription factor of light signaling, was found to inhibit shoot regeneration under a range of light conditions. 

本文中，作者发现光信号转导的关键转录因子HY5能够在各种光照条件下抑制植物的芽再生。 

结果1-HY5介导的芽再生抑制部分依赖于光：The heightened shoot regeneration capacity of the hy5-215 mutant was less marked in the dark than in the light, showing that HY5-mediated inhibition of shoot regeneration is partly light-dependent. 

黑暗条件下的hy5-215突变体芽再生效率增加要稍逊于光照条件，说明HY5介导芽再生抑制部分依赖于光照。

结果2-HY5-WUS/CLV3：The co-localization of WUSCHEL (WUS) and CLAVATA3 (CLV3) expressions was found to coincide with the initiation of stem cell niches in root explants during shoot regeneration. HY5 could directly repress CLV3 and WUS expression by binding to their respective promoters. 

作者发现在以根为外植体的芽再生过程中，WUS和CLV3基因表达的共定位与干细胞微环境（stem cell niches）相吻合。HY5能够通过结合到WUS和CLV3基因的启动子上，直接抑制这两个基因的表达。

结果3-HY5-AR12-WUS/CLV3：In parallel, HY5 indirectly repressed CLV3 and WUS by binding to the ARABIDOPSIS RESPONSE REGULATOR12 (ARR12) promoter. The resulting dual regulation exerted by HY5 on WUS and CLV3 impeded the initiation of shoot stem cell niches. 

同时，HY5还能够通过结合到ARR12基因的启动子上，间接抑制WUS和CLV3基因的表达。因此，HY5对于WUS和CLV3基因的双重调控阻止了茎干细胞微环境的起始。

结论：A HY5-mediated inhibitory pathway was identified which links cytokinin signaling and the pluripotency pathway during shoot regeneration.

本文的报道揭示了一个由光信号转导关键因子HY5介导的芽再生抑制网络，并且该网络将细胞分裂素信号转导和植物细胞多能性途径关联在一起。

** 向凤宁 **

doi: https://doi.org/10.1111/tpj.15703

Journal: the plant journal

First Published: February 07, 2022