Lead (Pb) is a heavy metal with high toxicity to plants. Root is the major organ to respond to Pb stress. However, little is known about how plant roots perceive Pb stress signaling. Here, we describe the transcriptome of Arabidopsis root tips under Pb stress using the RNA-seq assay. A total of 703 differentially expressed genes (DEGs) were identified and expressed at every time points. Some early-responsive DEGs (1 h) were predicted to be negatively involved in cell elongation and cell expansion, while some late-responsive DEGs (24 h) positively participated in defense of oxidative stress. Hydrogen peroxide (H2O2) and superoxide (O2−) were increased significantly in root tips under Pb stress. Cell wall extension related gene XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE 18 (XTH18) was induced in root tips, and xth18 showed reduced root growth inhibition by Pb stress. Our results revealed the potential mechanism of root growth inhibition by Pb stress and shed light for the further study.

中文翻译：

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通过拟南芥转录组分析鉴定铅胁迫下根系生长抑制相关基因

铅（Pb）是一种对植物具有高毒性的重金属。根是响应铅胁迫的主要器官。然而，人们对植物根系如何感知铅胁迫信号知之甚少。在这里，我们使用 RNA-seq 分析描述了在铅胁迫下拟南芥根尖的转录组。在每个时间点共鉴定并表达了 703 个差异表达基因 (DEG)。一些早期反应的 DEG（1 小时）被预测为消极参与细胞伸长和细胞扩张，而一些晚期反应的 DEG（24 小时）积极参与氧化应激的防御。在铅胁迫下，根尖的过氧化氢 (H2O2) 和超氧化物 (O2−) 显着增加。细胞壁延伸相关基因 XYLOGLUCAN EndotransGLUCOSYLASE/HYDROLASE 18 (XTH18) 在根尖被诱导，xth18 显示出 Pb 胁迫对根生长的抑制作用减弱。我们的研究结果揭示了铅胁迫抑制根系生长的潜在机制，并为进一步研究提供了依据。