Journal of Applied Microbiology (2022) 132, 2131-2143

Ameertha Ponnusamy, Ana Hazirah Ajis, Yee Shin Tan and Lay Ching Chai (2022)
Dynamics of fungal and bacterial microbiome associated with green-mould contaminated sawdust substrate of Pleurotus pulmonarius (grey oyster mushroom)
Journal of Applied Microbiology 132 (3), 2131-2143
Abstract:
Aims
Green-mould contamination is identified as one of the challenges faced by mushroom cultivation industry globally which believed to be caused by Trichoderma spp.
Methods and Results
To explore the dynamics of microbial population in mushroom substrate during commercial mushroom cultivation and how microbiota might play a role in green-mould contamination, we applied both culturing and targeted metagenomics approaches to identify microbiota in noncomposted sawdust substrates at different cultivation stages. The microbiological analysis showed that the green-mould contaminated substrates harboured higher total mesophilic bacteria count. The green-moulds isolated from the contaminated mushroom substrates were identified as Trichoderma pleurotum (n = 15; 93.8%) and Graphium penicillioides (n = 1; 6.3%). To our surprise, the targeted metagenomic analysis revealed that Graphium comprised 56.3% while Trichoderma consisted of only 36.1% of the total fungi population, suggesting that green-mould contamination might not be caused by Trichoderma alone, but also Graphium that grows very slowly in the laboratory.
Conclusion
It is worthwhile to note that G. penicillioides was also isolated in the early stages of mushroom cultivation, but not T. pleurotum. The results indicated that the structure and composition of the bacterial population in the mushroom substrate varied and the bacterial population shifted along the cultivation process.
Significance and Impact of Study
This study revealed a possibility of G. penicillioides as an overlooked fungi causing green-mould contamination.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Trichoderma pleurotum	Pleurotus (crop)	Malaysia