Inhibitory effect and enzymatic analysis of E-cinnamaldehyde against sclerotinia carrot rot

Abstract

This study was conducted to determine the inhibitory effect of E-cinnamaldehyde (EC) against causal agent of storage carrot rot, Sclerotinia sclerotiorum, under in vivo and in vitro conditions. Based on the results, EC was able to completely inhibit mycelial growth of three isolates (P>0.05) in both volatile and contact phases after 6days at the concentrations 200μl and 1μl/ml, respectively. In addition, EC at concentrations 1 and 10μl/ml completely inhibited carpogenic germination of three isolates. The results of in vivo trials showed that EC at the concentration of 10μl/ml was able to control the disease caused by isolates 1 and 3. However the disease caused by isolate 2 was inhibited with the concentration of 20μl/ml. In enzyme analyses, the activity of polyphenoloxidase and peroxidase did not change in the inoculated carrots after application of EC. Furthermore, the level of phenylalanine ammonia lyase decreased. These results indicated that EC does not have any potential to be considered as resistance inducers against sclerotinia carrot rot.

Keywords: Carrot dextrose agar; Contact phase; Mycelial growth; SAR; Volatile phase.