Antifungal activities of Rosmarinus extracts against Fusarium oxysporum, the pathogenic fungus of Anoectochilus stem rot.

BACKGROUND: Anoectochilus formosanus Hayata, a valuable medicinal herb. However, its quality and yield are severely compromised by stem rot disease caused by Fusarium oxysporum. Although this disease is commonly controlled with synthetic fungicides, their application poses environmental and health risks. Botanical fungicides, particularly plant extracts, offer safer alternatives. RESULTS: In this study, the extracts from Rosmarinus officinalis L. 'Severn Sea' and 'Majorca Pink' significantly inhibited F. oxysporum growth in vitro and mitigated stem rot symptoms in vivo. In addition, in vivo experiments showed that rosemary EEs increased stem weight and significantly reduced MDA and POD levels in susceptible plants. This is likely through upregulation of cathepsin F, calmodulin, and MAPK gene expression at the mRNA level. CONCLUSIONS: This study confirmed the in vitro antifungal activity of R. officinalis ethanolic extracts (EEs) against F. oxysporum as well as their in vivo immunoregulatory effects in A. formosanus. These findings highlight the potential of R. officinalis EEs for the development of botanical fungicides.