Genome-Wide Investigation of Apyrase (APY) Genes in Peanut ( L.) and Functional Characterization of a Pod-Abundant Expression Promoter

Peanut ( L.) is an important food and feed crop worldwide and is affected by various biotic and abiotic stresses. The cellular ATP levels decrease significantly during stress as ATP molecules move to extracellular spaces, resulting in increased ROS production and cell apoptosis. Apyrases () are the nucleoside phosphatase (NPTs) superfamily members and play an important role in regulating cellular ATP levels under stress. We identified 17 homologs in (), and their phylogenetic relationships, conserved motifs, putative miRNAs targeting different , -regulatory elements, etc., were studied in detail. The transcriptome expression data were used to observe the expression patterns in different tissues and under stress conditions. We found that the gene showed abundant expression in the pericarp. As the pericarp is a key defense organ against environmental stress and promoters are the key elements regulating gene expression, we functionally characterized the promoter for its possible use in future breeding programs. The functional characterization of in transgenic plants showed that it effectively regulated gene expression in the pericarp. GUS expression was also detected in flowers of transgenic plants. Overall, these results strongly suggest that are an important future research subject for peanut and other crops, and can be used to drive the resistance-related genes in a pericarp-specific manner to enhance the defensive abilities of the pericarp.