|LIU, T - Beijing Academy Of Agricultural Sciences
|DONG, DAN - Beijing Academy Of Agricultural Sciences
|ZHANG, TAOTAO - Beijing Academy Of Agricultural Sciences
|LI, JUN - Beijing University Of Chinese Medicine
|LIU, WEI-CHENG - Beijing Academy Of Agricultural Sciences
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2017
Publication Date: 3/25/2017
Citation: Liu, T., Meyer, S.L.F., Chitwood, D.J., Chauhan, K.R., Dong, D., Zhang, T., Li, J., Liu, W. 2017. New nematotoxic indoloditerpenoid produced by Gymnoascus reessii za-130. Journal of Agricultural and Food Chemistry. 65(15):3127-3132.
Interpretive Summary: Plant-parasitic nematodes annually cause crop losses of 100 billion dollars worldwide because of the lack of safe and effective methods and agents to control them. Fungi are a likely but inadequately investigated source of natural compounds for use in nematode management. In this study, a fungus isolated in China was found to produce a compound that was toxic to root-knot nematodes in laboratory studies and that suppressed nematode populations on tomato roots in greenhouse studies. These results are significant because the live fungus could potentially be used as a biological control agent for nematodes, or the compound applied as a biological nematicide. This work will be used by researchers involved in developing novel controls for reducing yield losses caused by plant-parasitic nematodes.
Technical Abstract: Chemical investigation of the fungal strain Gymnoascus reessii za-130, which was previously isolated from the rhizosphere of tomato plants infected by the root-knot nematode Meloidogyne incognita, led to the isolation and identification of a new indoloditerpenoid metabolite designated gymnoascole acetate. Its structure was established by spectroscopic methods including 1D- and 2D-NMR and MS analyses. Gymnoascole acetate demonstrated strong adverse effects on M. incognita second-stage juvenile (J2) viability; exposure to 36 µg/mL for 24 h induced 100% paralysis of J2 (EC50 = 47.5 µg/mL). Gymnoascole acetate suppressed M. incognita egg hatch relative to controls by >90% at 133 µg/mL after 7 days of exposure. The numbers of root galls and J2 in both soil and roots were significantly reduced (p = 0.05) by treatment with 2–200 µg/mL gymnoascole acetate/kg soil, compared to untreated control plants; nematode suppression increased with gymnoascole acetate concentration. This study demonstrated the nematotoxicity of gymnoascole acetate and indicates that it might be a potential biobased component in integrated management of M. incognita.