Allelochemical l-DOPA induces quinoprotein adducts and inhibits NADH dehydrogenase activity and root growth of cucumber

• Published in: Plant physiology and biochemistry 2013-09, Vol.70, p.374-378
• Main Authors: Mushtaq, Muhammad Naeem, Sunohara, Yukari, Matsumoto, Hiroshi
• Format: Article
• Language: English
• Subjects: Allelopathy; Biological and medical sciences; cucumbers; Cucumis sativus - drug effects; Cucumis sativus - growth & development; Cucumis sativus - metabolism; Fundamental and applied biological sciences. Psychology; growth retardation; L-dopa; Levodopa - pharmacology; mechanism of action; Melanin; Melanins - metabolism; mitochondria; Mitochondria - drug effects; Mitochondria - metabolism; Mitochondrial respiration; NAD (coenzyme); NADH dehydrogenase; NADH Dehydrogenase - antagonists & inhibitors; Pheromones - pharmacology; Plant physiology and development; Plant Proteins - metabolism; Plant Roots - drug effects; Plant Roots - growth & development; Plant Roots - metabolism; Quinoprotein; root growth; roots; Thiol; viability
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2013.06.003

Allelochemical l-DOPA (l-3,4-dihydroxyphenylalanine) inhibits growth of several plant species. However, its mode of action is not well clarified in plants. The present studies were conducted to explore the action mechanism of l-DOPA in cucumber roots. The results revealed that l-DOPA suppressed the root growth of cucumber and induced quinoprotein and melanin formation in the roots. Moreover, l-DOPA not only decreased mitochondrial viability and NADH dehydrogenase (complex I) activity but also increased quinoprotein formation in vitro in isolated mitochondria from cucumber roots. Strong correlations were observed between quinoprotein formation and root growth inhibition, quinoprotein formation and NADH dehydrogenase activity, after l-DOPA treatment. The results suggest that quinoprotein formation and mitochondrial impairment might be involved in growth-inhibition mechanism of l-DOPA in cucumber roots. [Display omitted] •l-DOPA suppressed root growth and enhanced melanin production in cucumber roots.•Quinoprotein formation was strongly correlated with root growth inhibition.•l-DOPA reduced mitochondrial viability and NADH dehydrogenase activity.•Quinoprotein formation and mitochondrial arrest may be involved in action of l-DOPA.