Isolation and identification of an allelopathic phenylethylamine in rice

Area of Science:

• Agricultural Science
• Plant Chemistry
• Ecology

Background:

• Allelopathy involves plant-released chemicals (allelochemicals) impacting other plants.
• Barnyard grass is a significant weed in rice cultivation, reducing yields.
• Specific rice cultivars may produce allelochemicals for weed control.

Purpose of the Study:

• To isolate and identify an allelopathic compound from a Vietnamese rice cultivar.
• To evaluate the efficacy of the identified compound against barnyard grass and other weeds.
• To assess the compound's release and production levels in rice plants.

Main Methods:

• Bioassay-guided purification using reversed-phase liquid chromatography.
• Spectroscopic techniques for compound identification: MS/MS, HRMS, 1D/2D NMR.
• Inhibition assays on weed seedlings (root/hypocotyl growth, mortality).

Main Results:

• N-trans-cinnamoyltyramine (NTCT), a β-phenylethylamine, was identified in rice cultivar OM 5930.
• NTCT significantly inhibited root and hypocotyl growth of barnyard grass and red sprangletop at low concentrations (0.24 μM).
• High seedling mortality (>80%) observed at 2.4 μM NTCT; significant NTCT release (0.425 nmol/seedling) and production (42 μg/g FW) in rice.

Conclusions:

• Vietnamese rice cultivar OM 5930 releases NTCT, demonstrating allelopathic potential.
• NTCT effectively suppresses barnyard grass and red sprangletop, suggesting its use as a bio-herbicide.
• The findings support the development of NTCT for sustainable weed management in agriculture.