The trehalose-6-phosphate synthase (TPS) gene family plays important roles in conferring plant stress resistance, but a comprehensive analysis of the gene family is lacking for sugarcane (Saccharum spp. hybrids). The objective of this study is to document functional classification, evolutionary characterization, and expression profiling of sugarcane TPS gene (ScTPS) family. Nine putative ScTPS genes were identified and assigned to two distinct classes based on gene structure and phylogeny. Phylogenetic analysis showed that 31 TPS genes from Arabidopsis, rice and sugarcane could be divided into five distinct clades, suggesting that there were at least five orthologous groups in monocot and dicot plants. Evolution analysis of TPS genes revealed that TPS family members appeared to have undergone strong negative selection. The strength of the selective pressure differed in most clades, especially Class I TPS genes, experienced significantly stronger negative selection pressure than Class II TPS genes. There were also cis-regulatory elements related to phytohormones and abiotic stresses. Additionally, ScTPS genes were found to exhibit divergent expression in response to simulated drought, salinity, and ABA stresses. Since ScTPS genes function in sugarcane adaptation to environmental stimuli, it might be used as a molecular marker in screening sugarcane germplasm for increased stress resistance.

TGA transcription factor (TF) family genes play a major role in the regulation of plant growth and development as well as in the defense against pathogen attack. Little is known about the TGA family genes and their functions in sugarcane. Here, a total of 16 TGA members were identified in the sugarcane genome by bioinformatic approaches. All members exhibited similar conserved motifs and contained a bZIP domain and a DOG1 domain, except for ShTGA15/16. Phylogenetic analysis demonstrated that 16 ShTGA family genes could be divided into eight clades, and evolved differently from Arabidopsis TGAs. All ShTGA family genes suffered a purifying selection during evolution. A wide range of cis-regulatory elements were found in the promoter of ShTGA genes including hormone regulatory elements, adversity response elements, light responsive elements, and growth and development regulatory elements. Most ShTGA expressions were increased in bud growth and developmental processes except for ShTGA10/11. It is worth noting that the expression of ShTGA13 was decreased after sugarcane was infected with Sporisorium scitamineum, and it was highly expressed in the resistant variety compared to the susceptible variety. Adding IAA, GA₃ and SA restored the expression of ShTGA13, suggesting an association with plant hormone regulatory pathways. Our study provides a framework for further functional studies of important ShTGA genes in development and stress response, and uncovered a previously unrecognized role of ShTGA13 in regulating resistance against S. scitamineum.