Transcriptome of peanut kernel and shell reveals the mechanism of calcium on peanut pod development

Calcium is not only a nutrient necessary for plant growth but also a ubiquitous central element of different signaling pathways. Ca(2+) deficiency in soil may cause embryo abortion, which can eventually lead to abnormal development of peanut pods during the harvest season. To further study the mechanisms by which Ca(2+) affects the shells and kernels of peanuts, transcriptome sequencing was used to explore the genes differentially expressed in shells and kernels during the early stage of peanut pod development between Ca(2+) sufficient and deficient treatments. In this study, 38,894 expressed genes were detected. RNA-seq based gene expression profiling showed a large number of genes at the transcriptional level that changed significantly in shells and kernels between the Ca(2+) sufficient and deficient treatments, respectively. Genes encoding key proteins involved in Ca(2+) signal transduction, hormones, development, ion transport, and nutrition absorption changed significantly. Meanwhile, in the early stage of pod development, calcium first promoted nutrient absorption and development of shells, which has less effect on the formation of seed kernels. These results provide useful information for understanding the relationship between Ca(2+) absorption and pod development.