Abstract Salt stress limits the regional distribution of Chinese cabbage, yet the molecular factors that confer tolerance to salt stress in Chinese cabbage remain poorly understood. To further investigate this issue, salt-tolerant and salt-sensitive Chinese cabbage cultivars were selected, and their responses to salt stress were tested. Then, comparative transcriptome profiling was performed on the roots of salt-tolerant and salt-sensitive Chinese cabbage cultivars under salt stress. The results showed that Qinghua and Biyu are considered to be salt-tolerant and salt-sensitive Chinese cabbage cultivars, respectively. Qinghua had higher water content and lower Na+/K+ in roots and leaves, better root development, higher lignin content and higher abscisic acid content in roots than Biyu. Comparative transcriptome profiling showed that the abscisic acid and ethylene signaling pathways of Qinghua roots were more actively expressed than those of Biyu. During root adaptation to salt stress, abscisic acid crosstalk with suberin biosynthesis and ethylene signaling crosstalk with lignin biosynthesis were observed. Suberin development and lignin accumulation in the Qinghua roots were found to be important strategies for resisting salt stress in this study. These strategies are not independent, but rather coordinate to promote salt tolerance in Chinese cabbage. The increased lignin content in the roots of Qinghua under salt stress may prevent embolism. Embolism prevention can maintain the flow of water transport, and thus compensate for the reduction in water permeability of these suberized cells in a process that occurs concurrently with greater sodium ion limitation. These results provide novel insight into the crosstalk of phenylpropanoid biosynthesis with hormone signaling under salt stress, and facilitate further dissection of molecular mechanism of adaptive response to salt stress in Chinese cabbage.

中文翻译：

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大白菜中苯丙烷生物合成与激素信号的串扰是抵消盐胁迫的关键

摘要 盐胁迫限制了大白菜的区域分布，但对大白菜耐盐胁迫的分子因素知之甚少。为了进一步研究这个问题，选择了耐盐和盐敏感的大白菜品种，并测试了它们对盐胁迫的反应。然后，对盐胁迫下耐盐和盐敏感的大白菜品种的根进行比较转录组分析。结果表明，清花和碧玉分别被认为是耐盐和盐敏感的大白菜品种。与碧玉相比，清花的根、叶含水量较高，Na+/K+较低，根系发育较好，根中木质素含量较高，脱落酸含量较高。比较转录组分析表明，清花根的脱落酸和乙烯信号通路比碧玉更活跃。在根适应盐胁迫的过程中，观察到脱落酸与木栓质生物合成的串扰和乙烯信号与木质素生物合成的串扰。在本研究中，发现清花根中的木栓质发育和木质素积累是抵抗盐胁迫的重要策略。这些策略不是独立的，而是协同促进大白菜的耐盐性。盐胁迫下青花根中木质素含量的增加可以预防栓塞。预防栓塞可以维持水运的畅通，从而在与更大的钠离子限制同时发生的过程中补偿这些栓化细胞的水渗透性的降低。这些结果为盐胁迫下苯丙烷生物合成与激素信号传导的串扰提供了新的见解，并有助于进一步剖析大白菜对盐胁迫的适应性反应的分子机制。