White mold on cultivated morels caused by Paecilomyces penicillatus

Abstract

Morchella (morel) includes prized edible and medical mushrooms in the world. Since 2012, commercial cultivation of morels in the field has developed rapidly in China. However, coupled with the rapid expansion of morel cultivation, diseases have been become serious threats to morel production. White mold is one of the most serious diseases on cultivated morels. This study aimed to confirm this pathogen by following Koch's postulates, and to identify it using molecular evidence. Our results indicated that healthy Morchella fruiting bodies inoculated with Paecilomyces sp. isolates produced typical white mold symptoms, and the internal transcribed spacer sequences of the Paecilomyces sp. were 99% similar to that recovered from an epitype of Paecilomyces penicillatus. Therefore, P. penicillatus was considered to be the causative agent of white mold. White mold occurred from the initial harvest to the storage and preservation process, and it produced white mold-like symptoms on the caps and stripes of Morchella. This is the first time that white mold has been reported on cultivated Morchella.

Genome Sequencing of Paecilomyces Penicillatus Provides Insights into Its Phylogenetic Placement and Mycoparasitism Mechanisms on Morel Mushrooms

“…White mold disease, caused by Paecilomyces penicillatus , is another major disease affecting morels. This disease was first reported in Sichuan, China in 2013 [ 7 ]. P. penicillatus infection in one location can quickly spread to neighboring morel cultivation areas and can account for up to 80% of morel yield losses.…”

Microbial communities associated with the black morel Morchella sextelata cultivated in greenhouses

“…Recently, methods for cultivating black morels (Elata clade) in soils under greenhouse environments were developed in China, leading to a significant increase in morel production. Morels are cultivated in non-axenic soils by planting fertile spawn in the soil, and feeding the mycelium with exogenous nutrient bags once it emerges from the soil (Guo et al, 2016; He et al, 2017; Liu et al, 2018a). However, as with other agronomic crops there is variability in production, and problems with diseases may occur during production (Guo et al, 2016; He et al, 2017; Liu et al, 2018a).…”

“…Morels are cultivated in non-axenic soils by planting fertile spawn in the soil, and feeding the mycelium with exogenous nutrient bags once it emerges from the soil (Guo et al, 2016; He et al, 2017; Liu et al, 2018a). However, as with other agronomic crops there is variability in production, and problems with diseases may occur during production (Guo et al, 2016; He et al, 2017; Liu et al, 2018a). Bacteria are thought to be responsible for the promotion of primordia differentiation and ascocarp growth, and may help suppress diseases (Liu et al, 2017).…”

The complete mitochondrial genome of Paecilomyces penicillatus (Hypocreales: Sordariomycetes)

“…Paecilomyces penicillatus was originally isolated from rotten mushrooms (Samson 1974). He et al (2017) demonstrated that P. penicillatus was the causative pathogen of morels which produced white mold-like symptoms on the caps and stripes of Morchella. Furthermore, P. penicillatus was not monophyletic, which had an uncertain affinity with the Clavicipitaceae within the Hypocreales (Luangsa-Ard et al 2005).…”

“…The strain was isolated from the diseased fruiting body of cultivated morels from Chengdu, Sichuan Province, China (103.87 E; 30.68 N). Koch's postulates, morphological features, and ITS sequences analysis showed that the strain was identical to the causative agent of white mould on cultivated Morchella (He et al 2017). The specimen (P. penicillatus) was stored in Sichuan Academy of Agricultural Sciences (No.…”