Genome-wide identification and abiotic stress responses of DGK gene family in maize

Abstract

Diacylglycerol kinase (DGK) is a kind of phosphokinase that catalyzes the formation of signaling molecule phosphatidic acid. In this study, seven maize (Zea mays) DGK gene family members were identified by an exploration of maize genome via multiple online databases, and designated as ZmDGK1-7, respectively. The proteins encoded by ZmDGKs ranged from 487 to 716 amino acids, and had a molecular weight (MWs) between 54.6 and 80.2 kDa. Phylogenetic analysis revealed that ZmDGKs grouped into three clusters as described for known plant DGK families: Cluster I was composed of three maize DGKs, ZmDGK1, ZmDGK4 and ZmDGK5, cluster II contained ZmDGK6, and the isoforms ZmDGK2, ZmDGK3 and ZmDGK7 fell into cluster III. ZmDGK proteins featured the typical functional domains, while all seven ZmDGKs have a conserved catalytic domain DGKc, only the cluster I ZmDGKs have the DAG/PE binding domain. Most ZmDGK genes showed ubiquitous expression profiles at various developmental stages, while a high relative expression was observed at the tasseling stage. ZmDGK genes exhibited differential expression patterns in response to abiotic stresses including cold, salinity and drought, and all ZmDGK genes were found obviously up-regulated by cold. The distinct roles of ZmDGKs in cold response was also supported by the finding that an accumulation of DGK products–PA under low temperature. This study will help to better understand the roles of DGKs in the development and abiotic stress responses in major crops.