*2.5. Major Transcription Factors Di*ff*erentially Regulated between "Variegatum" and "Green Pittosporum" under Cold Conditions*

Since the GO enrichment showed that differential binding activity was important for the cold responses in "Variegatum", we extended our study over the major transcription families (TF) present within the DEGs. In total, 11 down-regulated and 14 up-regulated TFs in "Variegatum" were detected. Among the down-regulated TFs, AP2-ERF, bHLH and MADS-box TFs were enriched (Figure 7A). Distinct TF families were enriched in the up-regulated genes and included NAC, WRKY, HSF and MYB (Figure 7B). Expression fold change of these TFs showed that two NAC genes (*c67871.graph\_c0* and *c63655.graph\_c1*) were strikingly up-regulated in "Variegatum" (Figure 7C) and may play prominent positive regulatory roles for cold stress endurance.

**Figure 7.** Major transcription factors (TF) families regulating cold response in *P. tobira*. (**A**) up-regulated TFs families in "Variegatum", (**B**) down-regulated TFs families in "Variegatum", (**C**) Log2 Fold change of the expression of TF genes.
