Cd胁迫下白车轴草根际原位酶谱分析及分子对接研究
- Response of rhizosphere enzyme activity and molecular docking of Trifolium repens L. under Cd stress
- 基金项目：国家大学生创新创业训练项目（230054）和沈阳市科技计划项目（22-322-3-01）
- 摘要：在分子尺度上解释重金属胁迫对典型土壤酶活性的影响机制，有助于构建更加可靠和具有靶向性的污染土壤修复技术。本文以镉(Cd)为目标污染物(浓度梯度1、3、5、10、15、20 mg·kg-1)、以白车轴草(Trifolium repens L.)为供试植物，利用原位酶谱研究了β-葡萄糖苷酶(3AHZ)、碱性磷酸酶(1ANI)、几丁质酶(1CTN)活性及根际空间分布特征，运用分子对接技术阐明了土壤酶-Cd互作机理。结果表明：3AHZ在Cd 浓度为5-15 mg·kg-1时热点面积上升幅度最显著，且活性高于空白对照组。Cd浓度<5 mg·kg-1时，根际1ANI可诱导兴奋效应，表现为酶热点面积增加。1CTN活性与Cd胁迫相关性不显著。分子对接结果表明：Cd2+可通过金属复合体键与酶的氨基酸残基结合，形成金属-蛋白质复合体，从而改变蛋白酶结构，影响其活性。研究结果可加深根际环境对重金属耐受和抗性的理解，能够为重金属土壤污染治理提供理论依据。
- Abstract：Explaining the impact mechanisms of heavy metal stress on typical soil enzyme activities at the molecular scale aids in developing more reliable and targeted remediation technologies for contaminated soils. In situ zymography was used to investigate the activity and rhizosphere spatial distribution characteristics of β-glucosidase (3AHZ), alkaline phosphatase (1ANI), and chitinase (1CTN) with cadmium (Cd) (with concentration gradients of 1, 3, 5, 10, 15, and 20 mg·kg-1) and Trifolium repens L. as the target pollutant and test plant, respectively, followed by the elucidation of the interaction mechanisms between soil enzymes and Cd by molecular docking technology. The results showed that the hotspot area of 3AHZ increased most significantly at Cd concentrations of 5-15 mg·kg-1, with activity higher than the control group. At Cd concentrations < 5 mg·kg-1, hormesis was observed for rhizosphere 1ANI, reflected by an increase in enzyme hotspot area. The activity of 1CTN showed no significant correlation with Cd stress. Molecular docking results indicated that Cd2+ can bind to amino acid residues of enzymes via metal complex bonds, forming metal-protein complexes that alter protease structure and affect their activity. These findings enhance the understanding of rhizosphere tolerance and resistance to heavy metals and provide a theoretical basis for the remediation of heavy metal-contaminated soils.
