Inhibitory activity of S61 and its active extracts on potato dry rot.

This study investigated the inhibitory activity of S61 and its active extract on potato dry rot pathogens and aimed at contributing to biocontrol agent development during potato storage. Three kinds of pathogens were isolated as target pathogenic fungi from dry rot tubers and determined as (Qing 9A-2), (Qing 9A-5-8) and (Qing 9A-1-1) by morphological and molecular identification. The strain S61 and its extract exhibited a higher inhibitory rate on both three pathogens (56.32-65.75 and 1.67-51.11%), notably the best suppression efficiency is presented in S61 and 40 mg/mL ethyl acetate extract. In terms of in vivo effects, both S61 and its ethyl acetate extract effectively reduced the decayed fruit and weight loss rate (0-20% and 7.59-16.56%) and enhanced the defensive enzymatic activities to improve resistance. In addition, strain S61 could be colonized on potato tubers, especially the highest amount of 1.55 × 10 CFU/mL on fifth day for variety Xiazhai 65. Overall, S61 and its ethyl acetate extract could be considered as potential approach for biocontrol potato dry rot.