Genome-Wide Identification of the TPP Gene Family in Chenopodium quinoa and Functional Characterization of CqTPP10 in Enhancing Salt Tolerance in Arabidopsis thaliana

Trehalose-6-phosphate phosphatase (TPP) is a key enzyme in trehalose biosynthesis and participates in endogenous sugar signaling regulation and abiotic stress adaptation in plants. We performed comprehensive bioinformatic analyses of the CqTPP gene family in Chenopodium quinoa, including physicochemical property evaluation, phylogenetic analysis, conserved motif identification, gene structure characterization, chromosomal localization, synteny analysis, and cis-acting elements prediction. In total, 12 CqTPP genes were identified and grouped into three distinct subgroups with obvious divergence in conserved motifs and gene structures. Segmental duplication dominated the expansion of the CqTPP gene family, and duplicated gene pairs underwent strong purifying selection. CqTPP genes shared high sequence homology with homologs from Beta vulgaris and Spinacia oleracea, and their promoters contained abundant stress-, hormone-, and light-responsive cis-acting elements. Transcriptome data revealed divergent salt-responsive expression patterns. Notably, CqTPP10 was persistently and significantly upregulated with prolonged salt treatment. Heterologous overexpression of CqTPP10 in Arabidopsis thaliana enhanced salt tolerance, improved seed germination, elevated SOD and POD activities, increased trehalose levels, reduced electrolyte leakage, reduced MDA and H2O2 accumulation, and downregulated KIN10. Collectively, this work provides comprehensive insight into the evolution and salt-response features of the quinoa CqTPP gene family and supplies promising candidate genetic resources for salt-tolerance improvement in crops.