*2.6. Promoter Sequence Analysis of Apple SAP Genes*

To investigate putative *cis*-acting elements in their promoter regions, we isolated approximately 1500-bp genomic sequences upstream of the start codon from our *MdSAPs*. Along with some *cis* elements involved in light-responsiveness (Table 2 and Supplementary File B3), we found that many were responsive to various stresses and correlative hormones. In total, 10 types of *cis* elements were discovered in the 13 promoters. They were associated with responses to hypoxia, heat, chilling, drought, pathogens, wounding, or hormones such as salicylic acid, methyl jasmonate, ABA, or ethylene. Therefore, we concluded that these *cis* elements play important roles in plant stress responses.

Sequences and functions for ABRE (ABA response element), ARE (anaerobic response element), CGTCA (MeJA-responsiveness), ERE (ethylene-responsive element), HSE (heat shock response element), LTR (low-temperature response element), MBS (MYB binding site involved in drought response), TCA (salicylic acid response element), TC-rich repeat (defense and stress responsiveness), and W-box (elicitation; wounding and pathogen responsiveness; binding site of WRKY type transcription factors) were obtained from the PlantCARE database (http://bioinformatics.psb.ugent. be/webtools/plantcare/html/). Digits represent the number of regulatory elements on plus/minus strand. Blank space indicates no corresponding cis-acting element in either strand of the promoter.



*Int. J. Mol. Sci.* **2018**, *19*, 2478

ABA: abscisic acid; ABRE: ABA response element; ARE: anaerobic response element; CGTCA: MeJA-responsiveness; ERE: ethylene-responsive element; HSE: heat shock response element; LTR: low-temperature response element; MBS: MYB binding site involved in drought response; TCA: salicylic acid response element; TC-Rich Repeat: defense and stress responsiveness; W-box: elicitation, wounding, and pathogen responsiveness/binding site of WRKY type transcription factors.
