Transcriptional activation by WRKY23 and derepression by removal of bHLH041 coordinately establish callus pluripotency in Arabidopsis regeneration
Transcriptional activation by WRKY23 and derepression by removal of bHLH041 coordinately establish callus pluripotency in Arabidopsis regeneration
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DOI：
10.1093/plcell/koad255
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发表时间：
2023-10-06
期刊：
影响因子：
11.6
通讯作者：
Hu，Yuxin
中科院分区：
文献类型：
--
作者：
Xu，Chongyi;Chang，Pengjie;Hu，Yuxin
从离体器官或组织诱导称为愈伤组织的多能细胞团是典型的体外植物再生的初始步骤，在此期间，生长素诱导的根干细胞因子的异位激活是随后的从头芽再生所必需的。拟南芥生长素反应因子7（ARF 7）和ARF 19及其下游转录因子LATERAL ORGAN BOUNDARIES DOMAIN（LBD）在诱导愈伤组织形成中起关键作用，但负责激活根干细胞因子从而建立愈伤组织多能性的分子尚不清楚。在这里，我们确定了拟南芥WRKY 23和碱性螺旋-环-螺旋041（bHLH 041）作为转录激活因子和阻遏物，分别在建立生长素诱导的愈伤组织多能性的根干细胞因子。我们发现生长素诱导的ARF 7和ARF 19下游的WRKY 23直接激活PLETHORA 3（PLT 3）和PLT 7的转录，从而激活下游基因PLT 1、PLT 2和WUSCHEL相关的HOMEOBOX 5（WOX 5）的转录，而LBD诱导的bHLH 041的去除解除了PLT 1、PLT 2和WOX 5的转录。我们提供的证据表明，转录激活WRKY 23和损失bHLH 041施加的镇压行为协同作用，赋予芽再生能力的愈伤组织细胞。因此，我们的研究结果揭示了一个转录机制的基础生长素诱导的细胞重编程，其中，连同以前的研究，概述了生长素诱导的多能愈伤组织形成的分子框架，在体外植物再生计划。
Induction of the pluripotent cell mass termed callus from detached organs or tissues is an initial step in typical in vitro plant regeneration, during which auxin-induced ectopic activation of root stem cell factors is required for subsequent de novo shoot regeneration. WhileArabidopsis(Arabidopsis thaliana) AUXIN RESPONSE FACTOR 7 (ARF7) and ARF19 and their downstream transcription factors LATERAL ORGAN BOUNDARIES DOMAIN (LBD) are known to play key roles in directing callus formation, the molecules responsible for activation of root stem cell factors and thus establishment of callus pluripotency are unclear. Here, we identifiedArabidopsisWRKY23 and BASIC HELIX-LOOP-HELIX 041 (bHLH041) as a transcriptional activator and repressor, respectively, of root stem cell factors during establishment of auxin-induced callus pluripotency. We show that auxin-induced WRKY23 downstream of ARF7 and ARF19 directly activates the transcription ofPLETHORA 3(PLT3) andPLT7and thus that of the downstream genesPLT1,PLT2, andWUSCHEL-RELATED HOMEOBOX 5(WOX5), while LBD-induced removal of bHLH041 derepresses the transcription ofPLT1,PLT2, andWOX5. We provide evidence that transcriptional activation by WRKY23 and loss of bHLH041-imposed repression act synergistically in conferring shoot-regenerating capability on callus cells. Our findings thus disclose a transcriptional mechanism underlying auxin-induced cellular reprogramming, which, together with previous studies, outlines the molecular framework of auxin-induced pluripotent callus formation for in vitro plant regeneration programs.