Abstract：Aquaporin (AQP) widely distributes throughout plants, mainly mediates the transmembrane transport of water and small molecule solutes, and plays an important role in plant growth and development in terms of water transport and stress resistance. Tigernut (Cyperus esculentus) is one of the oilseed crops with high oleic and linoleic acid content. In order to identify the AQP gene family and analyze its functions of tigernut, in this study, a total of 33 AQP genes were identified in tigernut using bioinformatics methods, which were analysed mainly in terms of phylogeny, physicochemical properties, gene structure, conserved motifs and promoter cis-acting elements, etc. qPCR was used to detect expression changes in selected members under salt stress. The results showed that members of the oilseed rape AQP gene family exhibited diversity in physicochemical properties such as amino acid content, protein molecular weight, and isoelectric point. Most AQP proteins demonstrated good stability, with subcellular localization studies showing the majority localized to the cell membrane and a minority to the vacuole. Based on phylogenetic relationships, the tigernut AQP gene family could be primarily classified into 4 subfamilies: PIP, TIP, SIP, and NIP, comprising 14, 10, 2 and 7 members, respectively. Genes within the same subfamily shared similar gene structures and conserved motifs, whereas differences existed between members of different subfamilies. Promoter cis-acting elements comprised 4 major categories: Light-responsive elements, plant hormone-responsive elements, growth and development-related elements, and abiotic stress-related elements. Among these, light-responsive elements were the most abundant, while growth and development-related elements were the least numerous. The expression of AQP gene family members in tigernut after salt stress treatment had different trends, suggesting their potential involvement in tigernut's salt stress response mechanisms. This study provides a reference for further functional analyses of water channel proteins.
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