Recently, the grass germplasm resource innovation and breeding application innovation team of the College of Grassland Science and Technology of Sichuan Agricultural University has made new progress in the physiological and molecular response mechanism of the heavy metal cadmium (Cd) stress of white trilobaste. The relevant results, “Physiological and Molecular Mechanisms of Response of White Trilobites to Cadmium Stress of Heavy Metals”, were published in the International Journal of Molecular Sciences. Through comprehensive analysis of physiological and biochemical indicators and comparative transcriptomics, the team revealed the physiological and molecular mechanisms of Cd stress tolerance of white trilobites, which provided a theoretical basis for plant remediation of white trilobites in Cd-contaminated soil.
This study found that most of the Cds are trapped in the roots of the white trilobite and are mainly fixed in the cell wall, while the Cd stress activates the antioxidant enzyme (SOD, POD, etc.) defense system in the white trilobite. Comparative transcriptome data showed that the differentially expressed genes of white trilobites under Cd stress were mainly enriched in metabolic pathways such as redox reaction, heavy metal transporter, MAPK signaling pathway-plant, glutathione synthesis, and phenylpropanin biosynthesis. Among them, the phenylpropanin bioabolic pathway is the main synthesis method of lignin, and Cd stress promotes the synthesis of lignin by inducing the upregulated expression of related genes in the white triloba. Lignin is the main component of the cell wall, and its biosynthesis can improve the binding efficiency of the cell wall to heavy metal ions. Glutathione (GSH) also plays an important role in the detoxifying effect of Cd. GSH can not only be used as a precursor to synthesize plant chelated peptides, chelate and fix Cd, and transport to vagaries through heavy metal transporters (ABC transporters, MATE transporters, etc.), but also participate in the removal of excess reactive oxygen species (ROS), and reduce the oxidative damage of plant cell membranes caused by Cd stress together with antioxidant enzyme systems (SOD, POD, HSP, etc.).
In short, there are two main ways for the tolerance of white trilobites to Cd under Cd stress: 1) enhance the biosynthesis of the cell wall by upregulating the genes of the phenylpropionin biosynthetic pathway, improve the cd fixation efficiency of the cell wall, and thus reduce the toxicity of Cd; 2) By upregulating glutathione metabolic pathway genes, promoting GSH synthesis, improving Cd chelation efficiency and inducing antioxidant systems to combat ROS accumulation, thereby improving the tolerance to Cd.
Diagram of the molecular response mechanism of the white trilobite to the heavy metal cadmium. Courtesy of College of Grassland Science and Technology, Sichuan Agricultural University
Postdoctoral Fellow Wu Feifei of college of grassland science and technology of Sichuan Agricultural University is the first author, and Associate Professor Nie Gang and Professor Zhang Xinquan are the corresponding authors. This study was funded by the National Modern Agricultural Industry Technology System, the 14th Five-Year Plan Breeding Research of Sichuan Province, and the Southern Grassland and Pasture Resources Project of the Ministry of Science and Technology. (Source: China Science Daily, Zhang Qingdan, Ma Xiaoyu)
Related paper information:https://doi.org/10.3390/ijms23094612