Genome-wide identification and characterization of the aquaporin gene family in Medicago truncatula

Abstract

Aquaporins (AQPs), or major intrinsic proteins (MIPs), constitute a large and diverse family of protein channel transporter in plants. However, the information about AQPs family is still poorly understood in the model legume species Medicago truncatula. Here, 46 AQPs were identified and characterized. Based on the phylogenetic analysis, these genes were assigned to five subfamilies, specifically as 10 plasma membrane intrinsic proteins, 12 tonoplast intrinsic proteins, 18 NOD26-like intrinsic proteins, 4 small basic intrinsic proteins and 2 uncharacterized intrinsic proteins. The essential information of AQPs, such as subcellular localization, gene structure, chromosomal localization, evolutionary stress and functional residues were systematically analyzed. In addition, in silico analysis of the gene expression profiles showed certain of tissue specificity and responsiveness to drought/salt stresses in some AQPs genes. The qRT-PCR results showed that MtPIP1;5 and MtTIP1;3 were significantly up-regulated under both drought and salinity stress conditions, indicated their important roles in response to abiotic stresses. The results could provide valuable information for the further functional analysis of the AQPs in M. truncatula and related legume species.