Kan Delong, Tian Minyu, Ruan Ying, Han Hui
Key Laboratory of Hunan Provincial on Crop Epigenetic Regulation and Development, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China.
Collaborative Innovation Center of Water Security for the Water Source Region of the Mid-Line of the South-to-North Diversion Project of Henan Province, Nanyang Normal University, Nanyang 473061, China.
Plants (Basel). 2024 Jul 21;13(14):1989. doi: 10.3390/plants13141989.
The application of phosphorus-solubilizing bacteria is an effective method for increasing the available phosphorus content and inhibiting wheat uptake of heavy metals. However, further research is needed on the mechanism by which phosphorus-solubilizing bacteria inhibit cadmium (Cd) uptake in wheat roots and its impact on the expression of root-related genes. Here, the effects of strain M2 on Cd absorption in wheat and the expression of root-related Cd detoxification and immobilization genes were determined. Compared with the control, strain M2 reduced (64.1-64.6%) Cd uptake by wheat roots. Cd fluorescence staining revealed that strain M2 blocked the entry of exogenous Cd into the root interior and enhanced the immobilization of Cd by cell walls. Forty-seven genes related to Cd detoxification, including genes encoding peroxidase, chalcone synthase, and naringenin 3-dioxygenase, were upregulated in the Cd+M2 treatment. Strain M2 enhanced the Cd resistance and detoxification activity of wheat roots through the regulation of flavonoid biosynthesis and antioxidant enzyme activity. Moreover, strain M2 regulated the expression of genes related to phenylalanine metabolism and the MAPK signaling pathway to enhance Cd immobilization in roots. These results provide a theoretical basis for the use of phosphorus-solubilizing bacteria to remediate Cd-contaminated fields and reduce Cd uptake in wheat.
施用解磷细菌是提高有效磷含量和抑制小麦吸收重金属的有效方法。然而，关于解磷细菌抑制小麦根系吸收镉（Cd）的机制及其对根系相关基因表达的影响，仍需进一步研究。在此，测定了菌株M2对小麦吸收Cd以及根系相关Cd解毒和固定基因表达的影响。与对照相比，菌株M2使小麦根系对Cd的吸收减少了（64.1-64.6%）。Cd荧光染色显示，菌株M2阻止了外源Cd进入根内部，并增强了细胞壁对Cd的固定作用。在Cd+M2处理中，47个与Cd解毒相关的基因上调，包括编码过氧化物酶、查尔酮合酶和柚皮素3-双加氧酶的基因。菌株M2通过调节类黄酮生物合成和抗氧化酶活性，增强了小麦根系对Cd的抗性和解毒活性。此外，菌株M2调节了与苯丙氨酸代谢和MAPK信号通路相关基因的表达，以增强根系对Cd的固定作用。这些结果为利用解磷细菌修复Cd污染土壤和减少小麦对Cd的吸收提供了理论依据。
