Lead exposure-induced defense responses result in low lead translocation from the roots to aerial tissues of two contrasting poplar species
Lead exposure-induced defense responses result in low lead translocation from the roots to aerial tissues of two contrasting poplar species
复制标题
铅暴露引起的防御反应导致两种对比杨树种的铅从根部到地上组织的转移量较低
DOI：
10.1016/j.envpol.2020.116346
复制
发表时间：
2021-02-15
影响因子：
8.9
通讯作者：
Luo, Zhi-Bin
中科院分区：
文献类型：
--
作者：
Shi, Wenguang;Zhou, Jing;Luo, Zhi-Bin
为了探讨铅 (Pb) 诱导的防御反应是否是造成根-枝 Pb 低易位的原因，我们将两种对比杨树的树苗（根-枝 Pb 易位相对较高的白杨和 Pb 易位较低的黑杨）暴露于 0 或 8 mM PbCl2。 P. nigra 中的 Pb 从根部到地上组织的转运比 P. x canescens 低 57%。与用 Pb 处理的 P. x canescens 相比，P. nigra 的根和地上组织中的 Pb 浓度较低，根生物量较大，并且根中 ROS 过量产生较低。与 P. x canescens 相比，P. nigra 根部具有更高比例的细胞壁 (CW) 结合 Pb 和水不溶性 Pb 化合物，以及与 Pb 液泡隔离相关的一些关键基因的转录水平更高，例如植物螯合素合成酶 1.1 (PCS1.1)、ATP 结合盒转运蛋白 C1.1 (ABCC1.1) 和 ABCC3.1 根。 Pb暴露诱导防御反应，包括黑松和黑松根中果胶和半纤维素含量的增加，草酸积累的增加，以及PCS1.1、ABCC1.1和ABCC3.1的转录上调。这些结果表明，黑杨根部更强的防御屏障可能与从根部到地上组织的铅易位较低有关，并且铅暴露诱导的防御反应可以增强杨树根部针对铅易位的屏障。 (C) 2020 Elsevier Ltd. 保留所有权利。
To explore whether lead (Pb)-induced defense responses are responsible for the low root-to-shoot Pb translocation, we exposed saplings of the two contrasting poplar species, Populus x canescens with relatively high root-to-shoot Pb translocation and P. nigra with low Pb translocation, to 0 or 8 mM PbCl2. Pb translocation from the roots to aboveground tissues was lower by 57% in P. nigra than that in P. x canescens. Lower Pb concentrations in the roots and aerial tissues, greater root biomass, and lower ROS overproduction in the roots were found in P. nigra than those in P. x canescens treated with Pb. P. nigra roots had higher proportions of cell walls (CWs)-bound Pb and water insoluble Pb compounds, and higher transcript levels of some pivotal genes related to Pb vacuolar sequestration, such as phytochelatin synthetase 1.1 (PCS1.1), ATP-binding cassette transporter C1.1 (ABCC1.1) and ABCC3.1 than P. x canescens roots. Pb exposure induced defense responses including increases in the contents of pectin and hemicellulose, and elevated oxalic acid accumulation, and the transcriptional upregulation of PCS1.1, ABCC1.1 and ABCC3.1 in the roots of P. nigra and P. x canescens. These results suggest that the stronger defense barriers in P. nigra roots are probably associated with the lower Pb translocation from the roots to aerial tissues, and that Pb exposure-induced defense responses can enhance the barriers against Pb translocation in poplar roots. (C) 2020 Elsevier Ltd. All rights reserved.