Comparative transcriptome analysis of transporters, phytohormone and lipid metabolism pathways in response to arsenic stress in rice (Oryza sativa)

Arsenic (As) contamination of rice (Oryza sativa) is a worldwide concern and elucidating the molecular mechanisms of As accumulation in rice may provide promising solutions to the problem. Previous studies using microarray techniques to investigate transcriptional regulation of plant responses to As stress have identified numerous differentially expressed genes. However, little is known about the metabolic and regulatory network remodelings, or their interactions with microRNA (miRNA) in plants upon As(III) exposure. We used Illumina sequencing to acquire global transcriptome alterations and miRNA regulation in rice under As(III) treatments of varying lengths of time and dosages. We found that the response of roots was more distinct when the dosage was varied, whereas that of shoots was more distinct when the treatment time was varied. In particular, the genes involved in heavy metal transportation, jasmonate (JA) biosynthesis and signaling, and lipid metabolism were closely related to responses of rice under As(III) stress. Furthermore, we discovered 36 new As(III)-responsive miRNAs, 14 of which were likely involved in regulating gene expression in transportation, signaling, and metabolism. Our findings highlight the significance of JA signaling and lipid metabolism in response to As(III) stress and their regulation by miRNA, which provides a foundation for subsequent functional research.