Integrated microbiome and metabolome analysis insights into microbial roles in poplar wetwood formation and control.

BACKGROUND

The globally distributed poplar wetwood disease causes huge economic losses. This study aims to elucidate the microbial communities and metabolite changes contribute to the formation of wetwood.

RESULTS

Comparative analysis reveals pathogens are enriched in wetwood. With the increase in tree age and disease index, the growth of microorganisms is inhibited and the stability of the microbial community is reduced. The key microorganisms vary with different ages and their metabolic activities affect the course of wetwood. The endophyte lignin-degrading Fusarium solani, cellulose- and hemicellulose-degrading Cladosporium, phenolic and organic acids-degrading Acinetobacter calcoaceticus, and Brenneria populi are involved in the occurrence of wetwood. Flavonoids account for the highest proportion in differential metabolites. In a pot experiment, Alternaria tenuissima, F. solani, Nigrospora and B. populi inoculated with healthy heartwood cause wetwood disease. The injection of exogenous salicylic acid promotes the occurrence of wetwood. Syringic acid, ampicillin and nystatin inhibit wetwood. Positive correlation between core microorganisms Brenneria and Desulfitobacterium with differential metabolites caffeic acid, cinnamic acid and salicylic acid indicated important role of Brenneria and Desulfitobacterium in the occurrence of wetwood disease.

CONCLUSION

The formation of poplar wetwood in Jianghan Plain involves the action of various microorganisms. © 2026 Society of Chemical Industry.