Genome-wide identification of the kiwifruit AcTPS family and analysis of its drought-responsive expression patterns

Drought stress severely restricts the growth, development, yield, and fruit quality of Actinidia chinensis, making it urgent to explore drought resistance genes and their regulatory mechanisms. Trehalose-6-phosphate synthase (TPS) genes are key genes involved in trehalose synthesis and metabolism, playing important roles in plant abiotic stress tolerance. Based on the genome database, transcriptome data, and leaf soluble sugar content analysis of A. chinensis, we investigated the response of A. chinensis and its AcTPS gene family to drought stress. Through bioinformatics and phylogenetic analysis, 13 AcTPS genes were identified, which were divided into two subfamilies and unevenly distributed across 11 chromosomes. Under drought stress, seven AcTPS genes showed significant expression changes, and five randomly selected genes were validated by qRT-PCR, with results highly consistent with the transcriptome data. Drought stress severely inhibited seedling growth, reduced leaf relative water content, and significantly promoted the accumulation of trehalose in A. chinensis leaves, indicating that the plant adapts to drought by regulating soluble sugar metabolism. Integrated transcriptomic and metabolomic analyses indicate that AcTPS1 may be related to trehalose biosynthesis, and a potential time-lag effect between trehalose content and AcTPS1 gene expression was observed. This study is limited to bioinformatics and omics analyses; AcTPS1 may be related to drought resistance in kiwi, but further functional validation is still required.