背景回顾：Plants display remarkable abilities to adjust growth and development to environmental conditions, such as the amount of available water. This developmental plasticity is apparent not only in root and shoot growth rates, but also in tissue patterning and cell morphology. 

前期研究：We have previously shown that in response to limited water availability, Arabidopsis thaliana root displays changes in xylem morphology, mediated by the non-cell-autonomous action of abscisic acid, ABA. 

主要发现：Here, we show, through analyses of ABA response reporters and tissue-specific suppression of ABA signaling, that xylem cells themselves act as primary signaling centers governing both xylem cell fate and xylem differentiation rate, revealing the cell-autonomous control of multiple aspects of xylem development by ABA.

结果1-ABA激活不同的VND转录因子，介导木质部发育调控的不同层面：ABA rapidly activates the expression of genes encoding VASCULAR-RELATED NAC DOMAIN (VND) transcription factors. Molecular and genetic analyses revealed that the two ABA-mediated xylem developmental changes are regulated by distinct members of this transcription factor family, with VND2 and VND3 promoting differentiation rate of metaxylem cells, while VND7 promotes the conversion of metaxylem toward protoxylem morphology. This phenomenon shows how different aspects of developmental plasticity can be interlinked, yet genetically separable. 

结果2-双子叶中，ABA介导的木质部发育调控网络具有演化保守性：Moreover, similarities in phenotypic and molecular responses to ABA in diverse species indicate evolutionary conservation of the ABA-xylem development regulatory network among eudicots. 

结论：Hence, this study gives molecular insights into how environmental stress modifies plant vascular anatomy and has potential relevance for water use optimization and adaptation to drought conditions.

 摘 要 

植物具有调整自身生长和发育，以适应环境的非凡能力，其中就包括可利用的水分。植物的这种发育可塑性不仅体现在地下和地上部分组织的生长速率，同时还表现在植物组织模式建成和细胞形态上。作者先前的研究显示，拟南芥在响应不足的水分供应时，其根会表现出木质部形态上的变化，而这是由脱落酸ABA的非细胞自主性活动所介导的。本文中，作者通过对ABA响应报告基因的分析以及组织特异性ABA信号转导的抑制，发现木质部的细胞本身作为初级信号中心，赋予了木质部细胞命运和木质部分化速率，揭示了由ABA对木质部发育的多个层面的细胞自主性调控。ABA能够快速激活VND转录因子的表达。分子和遗传分析显示，两个ABA介导的木质部发育变化受到该转录因子完全不同的基因所控制，其中，VND2和VND3促进后生木质部细胞的分化速率，而VND7促进后生木质部向原生木质部形态的转变。这一现象表明，发育可塑性的不同方面是如何相互联系的，但在遗传上又是可分离的。此外，不同物种对ABA的表型和分子响应具有相似性，表明真双子叶植物间ABA木质部发育调控网络的演化保守性。因此，本研究从分子水平揭示了环境胁迫对植物维管结构的影响，对于植物的水分利用优化和对干旱条件的适应具有潜在的意义。

 通讯作者 

** Annelie Carlsbecker **