Genome-Wide Identification of Cotton (Gossypium spp.) Trehalose-6-Phosphate Phosphatase (TPP) Gene Family Members and the Role of GhTPP22 in the Response to Drought Stress

Trehalose-6-phosphate phosphatase (TPP) is a key enzyme involved in trehalose synthesis in higher plants. Previous studies have shown that TPP family genes increase yields without affecting plant growth under drought conditions, but their functions in cotton have not been reported. In this study, 17, 12, 26 and 24 TPP family genes were identified in Gossypium arboreum, Gossypium raimondii, Gossypium barbadense and Gossypium hirsutum, respectively. The 79 TPP family genes were divided into three subgroups by phylogenetic analysis. Virus-induced gene silencing (VIGS) of GhTPP22 produced TRV::GhTPP22 plants that were more sensitive to drought stress than the control plants, and the relative expression of GhTPP22 was decreased, as shown by qRT–PCR. Moreover, we analysed the gene structure, targeted small RNAs, and gene expression patterns of TPP family members and the physicochemical properties of their encoded proteins. Overall, members of the TPP gene family in cotton were systematically identified, and the function of GhTPP22 under drought stress conditions was preliminarily verified. These findings provide new information for improving drought resistance for cotton breeding in the future.