First Isolation and Identification of Neopestalotiopsis clavispora Causing Postharvest Rot of Rosa sterilis and Its Control with Methyl Jasmonate and Calcium Chloride

Abstract

Postharvest rot is a major issue in fruit. However, the cause of postharvest rot on R. sterilis fruit has not been clarified, and there are few studies on the disease control. In this study, the fungus causing postharvest rot is isolated from the symptomatic R. sterilis fruit, and identified by morphological characteristic, pathogenicity test and molecular identification. Moreover, the effects of methyl jasmonate (MeJA) or calcium chloride (CaCl2) alone and their combination on disease resistance to fruit rot were assessed by the determination of defense-related enzyme activity and other indicators. N. clavispora was identified as the main fungus causing the postharvest rot of R. sterilis fruit. The infected fruits were treated with MeJA and CaCl2, and these partially controlled the disease, were additive in effectiveness when used together, increased retention of vitamin C content and fruit firmness, and both enhanced and improved the retention of PAL, POD and PPO activities. The treatment of 500 μL/L MeJA and 3% CaCl2 resulted in the high inhibition of the disease. To our knowledge, this is the first report of N. clavispora causing R. sterilis fruit rot, and the combined treatment is a promising method for controlling postharvest rot on R. sterilis fruit.