Soil water uptake by roots is a key component of plant performance and adaptation to adverse environments. Here, we use a genome-wide association analysis to identify the XYLEM NAC DOMAIN 1 (XND1) transcription factor as a negative regulator of Arabidopsis root hydraulic conductivity (Lp_r). The distinct functionalities of a series of natural XND1 variants and a single nucleotide polymorphism that determines XND1 translation efficiency demonstrate the significance of XND1 natural variation at species-wide level. Phenotyping of xnd1 mutants and natural XND1 variants show that XND1 modulates Lp_r through action on xylem formation and potential indirect effects on aquaporin function and that it diminishes drought stress tolerance. XND1 also mediates the inhibition of xylem formation by the bacterial elicitor flagellin and counteracts plant infection by the root pathogen Ralstonia solanacearum. Thus, genetic variation at XND1, and xylem differentiation contribute to resolving the major trade-off between abiotic and biotic stress resistance in Arabidopsis.

中文翻译：

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XND1处的自然变化影响根系水力学和拟南芥中应力响应的权衡。

根部吸收土壤水分是植物生长和适应不利环境的重要组成部分。在这里，我们使用全基因组关联分析来确定XYLEM NAC DOMAIN 1（XND1）转录因子作为拟南芥根水力传导率（Lp _r）的负调节剂。一系列天然XND1变体的不同功能和决定XND1翻译效率的单核苷酸多态性证明了XND1自然变体在全物种水平上的重要性。Xnd1突变体和天然XND1变异的表型表明XND1调节Lp _r通过对木质部形成的作用以及对水通道蛋白功能的潜在间接影响，降低了干旱胁迫的耐受性。XND1还介导了细菌引发鞭毛蛋白对木质部形成的抑制作用，并抵消了根部病原体青枯菌（Ralstonia solanacearum）对植物的感染。因此，XND1的遗传变异和木质部的分化有助于解决拟南芥中非生物和生物胁迫抗性之间的主要权衡。