Abstract
Phytoene synthase plays important roles in the development, metabolism, and various stress tolerance in plants. In the current study, a total of five tobacco phytoene synthase members were identified and systemically analyzed from the latest genome annotation. The newly identified tobacco members were divided into different subgroups together with the reported members. Furthermore, four NtPSY genes were identified to arise from duplication events, which might lead to the expansion of tobacco phytoene synthase members. The expression patterns of the NtPSY genes were revealed by transcriptomic analysis. The results from phylogenetic analysis, synthetic analysis, and expression analysis were integrated to predict the potential functions of these tobacco phytoene synthase members. Particularly, NtPSY1 was found to act as the homolog of SlPSY1, which was significantly induced by cold stress treatment. The further assays revealed that overexpression of NtPSY1 enhanced the carotenoid accumulation and cold stress tolerance in transgenic tobacco. Furthermore, the transcript levels of NtCCD7, NtCCD8, and NtMAX1 were detected to be increased in the NtPSY1 overexpression lines, suggesting the enhanced carotenoid precursor supply and activation of the strigolactone biosynthetic pathway.