Characterization of Genes in Pepper and Functional Analysis of in Cold and Salt Stress.

As a subfamily of basic helix-loop-helix (bHLH) transcription factors, phytochrome-interacting factors (PIFs) participate in regulating light-dependent growth and development of plants. However, limited information is available about PIFs in pepper. In the present study, we identified six pepper genes using bioinformatics-based methods. Phylogenetic analysis revealed that the PIFs from pepper and some other plants could be divided into three distinct groups. Motif analysis revealed the presence of many conserved motifs, which is consistent with the classification of PIF proteins. Gene structure analysis suggested that the genes have five to seven introns, exhibiting a relatively more stable intron number than other plants such as rice, maize, and tomato. Expression analysis showed that was up-regulated by cold and salt treatments. -silenced pepper plants obtained by virus-induced gene silencing (VIGS) exhibited higher sensitivity to cold and salt stress, with an obvious increase in relative electrolyte leakage (REL) and variations in the expression of stress-related genes. Further stress tolerance assays revealed that plays different regulatory roles in cold and salt stress response by promoting the expression of the gene and ABA biosynthesis genes, respectively. Our results reveal the key roles of in cold and salt tolerance of pepper, and lay a solid foundation for clarifying the biological roles of in pepper and other plants.