Transcriptome analysis revealed that jasmonic acid biosynthesis/signaling is involved in plant response to Strontium stress

Strontium (Sr) has become an increasing global threat for both environment and human health due to its radioactive isotope, Sr-90 which can be found in the nuclear-contaminated soils and water. Although excessive Sr has been known to be toxic to plant growth and development, the molecular mechanisms underlying plant response to Sr stress, especially on the transcription level, remains largely unknown. To date, there is no published genome-wide transcriptome data available for the plant responses to Sr toxicity. Therefore, we aimed to gain insight on the molecular events occurring in plants in Sr toxicity condition by comparing the genome-wide gene expression profiles between control and Sr-treated plants using RNA-seq analysis. A total of 842 differentially expressed genes (DEGs) were identified in response to Sr stress compared to the control. Based on the analysis of DEGs using Gene Ontology (GO), DEGs were significantly enriched in the GO terms of response to salicylic acid (SA), response to jasmonic acid (JA), and defense response to bacterium. In addition, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis indicated that DEGs were mainly involved in metabolic processes including phenylpropanoid biosynthesis and alpha-linolenic acid metabolism, which is known as a precursor of JA biosynthesis. Furthermore, MapMan analysis revealed that a number of genes related to the biotic stress such as pathogenesis-related protein (PR) genes were highly up-regulated under Sr stress. Taken together, this study revealed that JA biosynthesis and/or signaling might be associated with plant response to Sr stress, and play important roles to maintain proper growth and development under Sr stress.