Molecular mechanism of Arabidopsis thaliana seedlings in response to phytotoxicity of yttrium oxide nanoparticles

Due to the wide application of rare earth oxides nanoparticles in different fields, they will inevitably be released into the environment, and their potential toxicity and ecological risks in the environment have become a concern of people. Yttrium oxide nanoparticles are important members of rare earth oxides nanoparticles. The molecular mechanism of its influence on plant growth and development and plant response to them is unclear. In this study, we found that yttrium oxide nanoparticles above 2 mM significantly inhibited the growth of Arabidopsis seedlings. Using the Arabidopsis marker lines reflecting auxin signal, it was found that the treatment of yttrium oxide nanoparticles led to the disorder of auxin signal in root cells: the auxin signal in quiescent center cells and columella stem cells decreased; while the auxin signal in the stele cells was enhanced. In addition, trypan blue staining showed that yttrium oxide nanoparticles caused the death of root cells. Transcriptome sequencing analysis showed that yttrium oxide nanoparticles specifically inhibited the expression of lignin synthesis related genes, activated mitogen-activated protein kinase (MAPK) signaling pathway, and enhanced ethylene and ABA signaling pathways in plants. This study revealed the phytotoxicity of yttrium oxide nanoparticles at the molecular level, and provided a new perspective at the molecular level for plants to respond to rare earth oxide stress. Comparative gene expression profiling analysis of RNA-seq data for Arabidopsis seedlings treated with yttrium oxide nanoparticles and the control group.