Transcriptome analysis of peanut (Arachis hypogaea) in response to aluminum stress

Peanut appears to be one of Al-tolerant plants; however, low yields of peanut grow on acid soil. The molecular mechanisms underlying peanut responses to Al stress are largely unknown. Here, we performed transcriptome analysis of the root tips(0-1 cm) of peanut cultivar ZH2(Al-sensitive) and 99-1507(Al-tolerant) respectively with regards to early response (first 8 h) and late response (24 h) to Al stress (100 µM), which is important for identification of genes and processes involved in Al toxicity and tolerance mechanisms. A total of 2875 and 2476 differentially expressed genes (DEGs) were identified in 99-1507 and ZH2, respectively. Among the DEGs, most were up-regulated at (8 h) in 99-1507. In ZH2, most DEGs determined between 8h and 24h Al-treatment groups were up-regulated. We performed GO and KEGG pathway enrichment analyses, and excavated a group of important Al-responsive genes related to organic acid secretion, organic acid transport, metal cation transport, gene expression regulation and PCD process. A number of transcription factors, including STOP2, WRYKs and NACs, as well as genes related to organic acid metabolism and transport were identified as Al-induced genes in this study. These homologs imply some common and distinct Al-tolerant mechanism between peanut and other species, and are promising targets to modulate Al tolerance in peanuts. The lag increments of the gene expression on the whole scale might be an important reason to affect Al resistance in ZH2.