Identification and Analysis of Phosphatidylethanolamine-Binding Protein Family Genes in the Hangzhou White Chrysanthemum (Chrysanthemum morifolium Ramat)

The Hangzhou White Chrysanthemum (Chrysanthemum morifolium Ramat) is one of the "Zhejiang eight flavors" in traditional Chinese medicine. The phosphatidylethanolamine-binding protein (PEBP) plays an important role in flowering and floral organ development. Even so, the biological role of PEBPs in the Hangzhou White Chrysanthemum has not been studied, which attracted us. Here, nine CmPEBP genes that contain the PF01161 domain were identified in the Hangzhou White Chrysanthemum for the first time, and their biological role in flowering was preliminarily studied. A phylogenetic analysis classified the CmPEBP genes into three subfamilies: MFT-like, TFL-like, and FT-like genes. The differential expression analysis was performed under different tissues and different stressors using qRT-PCR. It showed that each CmPEBP displayed tissue-specific expression patterns. Expression patterns in response to different temperatures and hormone stressors were investigated. They were finally demonstrated to be differentially expressed. TFL-like gene expression, which delayed reproductive growth, was upregulated under heat stress. Conversely, FT-like gene expression was upregulated under low temperatures. CmFT1 expression could be inhibited by GA (gibberellin), 6-BA (benzylaminopurine), ET (ethylene), and MeSA (methyl salicylate) but could be activated by IAA (indole-3-aceticacid), ABA (abscisic acid), and SA (salicylic acid) in the dark, whereas CmFT2 and CmFT3 expression levels were upregulated by ET, MeJA (methyl jasmonate), and ABA but were downregulated by 6-BA, SA, and MeSA. GA, IAA, SA, and MeSA inhibited CmTFL gene expression under light and dark treatments. Further research on CmPEBP genes in the Hangzhou White Chrysanthemum could better determine their roles in flowering and floral organ development, especially in response to the prolonged spraying of exogenous hormones.