Abstract
BACKGROUND: Trehalose-6-phosphate synthase (TPS) is an essential enzyme for synthesizing trehalose and is a significant regulator of plant development and stress response. Sweet orange (Citrus sinensis) is an economically important fruit tree crop and a common transgenic material. At present, little information is available about the TPS gene family in sweet orange. METHODS: The TPS gene family were identified from sweet orange genome by bioinformatics analysis. Additionally, the expression of CisTPS genes was analyzed under phytohormones and abiotic stresses by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). RESULTS: Here, eight TPS genes were identified and were found to be randomly distributed in five sweet orange chromosomes. TPS and trehalose-6-phosphate phosphatase (TPP) domains were observed in all CisTPS proteins. The phylogenetic tree showed that CisTPS genes were divided into two subfamilies, and genes in each subfamily had conserved intron structures and motif compositions. The cis-acting elements of CisTPS genes suggested their roles in phytohormone and stress responses. All CisTPS genes were ubiquitously expressed in roots, leaves, and stems, and six members were highly expressed in roots. Expression profiles showed that CisTPS genes exhibited tissue specificity and were differentially expressed in response to phytohormones and abiotic stresses. This study lays a foundation for revealing the functions of the TPS gene family in trehalose regulation in sweet orange, and provides a valuable reference for this gene family in other plants.