Application of the mushroom volatile 1-octen-3-ol to suppress a morel disease caused by Paecilomyces penicillatus.

Morels (Morchella spp.) are of great economic and scientific value. Paecilomyces penicillatus can cause white mold disease (WMD) widely emerging on morel ascocarps and is also a potential factor causing morel fructification failure. 1-octen-3-ol is a mushroom volatile compound with broad-spectrum antimicrobial activities. This study aimed to control the morel disease caused by P. penicillatus through suppressing P. penicillatus in the soil cultivated with Morchella sextelata using 1-octen-3-ol. Safe concentration of 1-octen-3-ol was estimated by comparing its inhibitory effect against P. penicillatus and M. sextelata, respectively, with mycelium-growth experiments on agar plates. The results showed that M. sextelata possesses a higher tolerance to 1-octen-3-ol than P. penicillatus with a 1-octen-3-ol concentration between 0 and 200 µL/L. Based on that, a sandy soil was supplemented with low (50 µL/L) or high concentration (200 µL/L) of 1-octen-3-ol. The effects of 1-octen-3-ol on soil microbial communities, WMD incidence, and morel yield were investigated. Compared to the non-supplemented control group, the incidence of WMD and the proportion of Paecilomyces in the soils of low- and high-concentration treatment groups were significantly decreased, corresponding to a significant increase in morel ascocarp yield. It suggests that 1-octen-3-ol effectively suppressed P. penicillatus in the soil, thereby reducing the severity of WMD and improving the morel yield. The diversity of soil bacterial communities was also altered by 1-octen-3-ol supplement. The proportion of Rhodococcus spp. in the soil was positively correlated with the 1-octen-3-ol concentration and ascocarp yield, suggesting its potential role in improving morel yield. KEY POINTS: • A novel method for morel disease suppression was proposed. • Paecilomyces in soil affects white mold disease and fructification yield of morel. • 1-Octen-3-ol suppresses Paecilomyces and alters bacterial community in soil.