In our study, ACC content (figure 3a), expression level of CoACO1 and CoACO2 (figure 6a) and ACO activity (figure 3c) significantly increased in AZs of AF compared with that of NF which indicated that the whole ethylene biosynthesis pathway has been upregulated when fruits are close to abscission. The gene discussed is KLK15; the disease is atrial fibrillation.