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2018年1月22日,Nature Plants在线发表了题为“Control of auxin-induced callus formation by bZIP59–LBD complex in Arabidopsis regeneration”的文章。
文章由中国科学院植物研究所植物分子生理学重点实验室胡玉欣研究员课题组完成。
愈伤组织(callus)原指植物体的局部受到创伤刺激后,在伤口表面新生的组织。它由活的薄壁细胞组成,可起源于植物体任何器官内各种组织的活细胞。
在植物的组织培养中,从一块外植体形成典型的愈伤组织,大致要经历三个时期:启动期、分裂期和形成期。生长素对诱导细胞开始分裂效果很好。
本文即揭示了AtbZIP59-LBD复合物在调控生长素诱导愈伤组织形成的分子机制,由此对生长素如何诱导愈伤组织的形成有了更深入的理解。
摘要:
生长素诱导多能细胞愈伤组织的形成,代表了植物体外再生所需的典型的细胞命运变化;然而,生长素诱导愈伤组织形成的分子机制很大程度上是未知的。我们以前确定了拟南芥中四个生长素诱导的LBD转录因子,它们控制愈伤组织形成。在这里,我们报道了拟南芥转录因子AtbZIP59与LBDs形成复合物,调控生长素诱导的愈伤组织形成。结果显示,生长素稳定AtbZIP59,并促进其与LBD的相互作用。AtbZIP59的破坏抑制生长素诱导的愈伤组织形成,而AtbZIP59的过表达则触发愈伤组织自发形成。AtbZIP59-LBD16复合物直接靶向FAD-BD基因并促进其转录,这有助于愈伤组织形成。这些发现表明,在愈伤组织形成过程中,AtbZIP59-LBD复合物是生长素诱导的细胞命运变化的关键调节剂,这为植物再生的分子调控和可能的发育程序提供了新的见解。
Abstract:
Induction of pluripotent cells termed callus by auxin represents a typical cell fate change required for plant in vitro regeneration; however, the molecular control of auxin-induced callus formation is largely elusive. We previously identified four Arabidopsis auxin-inducible Lateral Organ Boundaries Domain (LBD) transcription factors that govern callus formation. Here, we report that Arabidopsis basic region/leucine zipper motif 59 (AtbZIP59) transcription factor forms complexes with LBDs to direct auxin-induced callus formation. We show that auxin stabilizes AtbZIP59 and enhances its interaction with LBD, and that disruption of AtbZIP59 dampens auxin-induced callus formation whereas overexpression of AtbZIP59 triggers autonomous callus formation. AtbZIP59–LBD16 directly targets a FAD-binding Berberine (FAD-BD) gene and promotes its transcription, which contributes to callus formation. These findings define the AtbZIP59–LBD complex as a critical regulator of auxin-induced cell fate change during callus formation, which provides a new insight into the molecular regulation of plant regeneration and possible developmental programs.
Fig. 2 | AtbZIP59 mediates auxin-inducible callus formation
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