Transcriptome analysis reveals salt-stress-regulated biological processes and key pathways in roots of peanut (Arachis hypogaea L.)

The cultivated peanut is important oil crop and salt stress seriously influences its development and yield. Tolerant varieties produced using transgenic techniques can effectively increase peanut plantation area and enhance its yields. However, little is known about how gene expression is regulated by salt stress in peanut. In this study, we screened genes regulated by salt stress in peanut roots using microarray technique. In total, 4828 up-regulated and 3752 down-regulated probe sets were successfully identified in peanut roots subjected to 3 and 48 h of salt stress. Data analysis revealed that different response groups existed between the up and down-regulated probe sets. The main up-regulated biological processes involved in salt stress responses included transcription regulation, stress response, and metabolism and biosynthetic processes. The main down-regulated biological processes included transport processes, photosynthesis and development. The Kyoto encyclopedia of genes and genomes pathway analysis indicated that metabolic pathway, biosynthesis of unsaturated fatty acids and plant–pathogen interaction, were mainly up-regulated in peanut under salt stress. However, photosynthesis and phenylalanine metabolism were mainly down-regulated during salt stress. The function of some probe sets in salt stress regulation was not clarified (e.g., protein functioning in cell cycle regulation and xylem development). Many of the genes we identified lacked functional annotations and their roles in response to salt stress are yet to be elucidated. These results identified some candidate genes as potential markers and showed an overview of the transcription map, which may yield some useful insights into salt-mediated signal transduction pathways in peanut.