RESEARCH ARTICLE Transcriptome profiling of

http://www.biomedcentral.com/1471-2164/14/517photo period. When the elongating gynophore pushes2College of Agriculture, Shandong University, Jinan 250100, PR China Full list of author information is available at the end of the articleBackground Peanut (Arachis hypogaea L.) is a world-wide important crop both for oil and protein production. In recent years, great advances have been achieved in peanut functional genomics, proteomics, molecular marker development and other biotechnological based research areas. However, little studies focused on understanding the key biological processes in peanut plants as for instance, the molecular mechanism of peanut geocarpy, which was investigated from the physiological aspect in last century [1-6]. Peanut flowers and finishes pollination above ground as other plants. After fertilization, the activity of an intercalary meristem at the base of the ovary leads to the formation of a gynophore. It carries the ovary and grows in a positive geotropic manner [7]. The zygote cell divides only few times and then both the pre-embryo and pod development are arrested in continuous sun light or regular day/nigh