Auxin-Induced WUSCHEL-RELATED HOMEOBOX13 Mediates Asymmetric Activity of Callus Formation upon Cutting
Auxin-Induced WUSCHEL-RELATED HOMEOBOX13 Mediates Asymmetric Activity of Callus Formation upon Cutting
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DOI：
10.1093/pcp/pcac146
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发表时间：
2023-01-31
影响因子：
4.9
通讯作者：
Ikeuchi, Momoko
中科院分区：
文献类型：
--
作者：
Tanaka, Hayato;Hashimoto, Naoki;Ikeuchi, Momoko
植物具有重新连接切割器官的再生能力，这在生理上对严重组织损伤的生存非常重要。将器官重新连接的能力用作嫁接以将两个不同的个体联合收割机结合。移植物连接处的愈伤组织形成有利于器官附着和血管重新连接。虽然有充分的证据表明局部创伤信号引起愈伤组织形成，但愈伤组织形成在每个切割端如何受到差异调节仍然是难以捉摸的。在这里，我们报告说，愈伤组织的形成活动是不对称的顶部和底部切割结束，并调节差异生长素积累。基因表达分析表明，细胞生长素反应优先上调的顶部的移植。极性生长素运输的中断抑制愈伤组织的形成从顶部，而外部应用的生长素是足以诱导愈伤组织的形成从底部，这表明不对称的生长素积累是负责从顶端活跃的愈伤组织的形成。我们进一步发现，愈伤组织形成的关键调节因子WUSCHEL相关同源框13（WOX13）的表达受生长素诱导。异位愈伤组织的形成从底端，这是由局部补充生长素触发，需要WOX13的功能，表明WOX13在生长素依赖性愈伤组织的形成中起着关键作用。在嫁接的叶柄和切开的花序茎中都观察到了不对称的WOX13表达，这强调了我们研究结果的普遍性。我们建议，有效的器官重新连接是通过局部创伤刺激和中断的长距离信号的组合实现的。
Plants have the regenerative ability to reconnect cut organs, which is physiologically important to survive severe tissue damage. The ability to reconnect organs is utilized as grafting to combine two different individuals. Callus formation at the graft junction facilitates organ attachment and vascular reconnection. While it is well documented that local wounding signals provoke callus formation, how callus formation is differentially regulated at each cut end remains elusive. Here, we report that callus formation activity is asymmetrical between the top and bottom cut ends and is regulated by differential auxin accumulation. Gene expression analyses revealed that cellular auxin response is preferentially upregulated in the top part of the graft. Disruption of polar auxin transport inhibited callus formation from the top, while external application of auxin was sufficient to induce callus formation from the bottom, suggesting that asymmetric auxin accumulation is responsible for active callus formation from the top end. We further found that the expression of a key regulator of callus formation, WUSCHEL-RELATED HOMEOBOX 13 (WOX13), is induced by auxin. The ectopic callus formation from the bottom end, which is triggered by locally supplemented auxin, requires WOX13 function, demonstrating that WOX13 plays a pivotal role in auxin-dependent callus formation. The asymmetric WOX13 expression is observed both in grafted petioles and incised inflorescence stems, underscoring the generality of our findings. We propose that efficient organ reconnection is achieved by a combination of local wounding stimuli and disrupted long-distance signaling.