Isolation and functional characterization of a novel seed-specific promoter region from peanut

The importance of using tissue-specific promoters in the genetic transformation of plants has been emphasized increasingly. Here, we report the isolation of a novel seed-specific promoter region from peanut and its validation in Arabidopsis and tobacco seeds. The reported promoter region referred to as groundnut seed promoter (GSP) confers seed-specific expression in heterologous systems, which include putative promoter regions of the peanut (Arachis hypogaea L.) gene 8A4R19G1. This region was isolated, sequenced, and characterized using gel shift assays. Tobacco transgenics obtained using binary vectors carrying uidA reporter gene driven by GSP and/or cauliflower mosaic virus 35S promoters were confirmed through polymerase chain reaction (PCR), RT-PCR, and computational analysis of motifs which revealed the presence of TATA, CAAT boxes, and ATG signals. This seed-specific promoter region successfully targeted the reporter uidA gene to seed tissues in both Arabidopsis and tobacco model systems, where its expression was confirmed by histochemical analysis of the transgenic seeds. This promoter region is routinely being used in the genetic engineering studies in legumes aimed at targeting novel transgenes to the seeds, especially those involved in micronutrient enhancement, fungal resistance, and molecular pharming.