L-DOPA induces iron accumulation in roots of Ipomoea aquatica and Arabidopsis thaliana in a pH-dependent manner

Botanical Studies

Original Article

Ching-Yuan Chang¹  Chu-Han Tseng¹  Louis Grillet¹  En-Jung Hsieh¹  Shan-Li Wang¹  Siao-Wei Liao¹ 

[1] College of Agriculture and Bioresources, Department of Agricultural Chemistry, National Taiwan University, Building No. 2, Rm. 209A No. 1, Sec. 4, Roosevelt Rd, 10617, Taipei, Taiwan;

关键词: L-DOPA;    Water spinach;    Allelopathy;    pH;    Iron;   

DOI  :  10.1186/s40529-023-00396-7

 received in 2023-07-06, accepted in 2023-08-14,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundIron deficiency is the leading cause of anemia worldwide, particularly in countries with predominant plant-based diets. Plants constitute the main source of dietary iron. Increasing their iron concentration could reduce the occurrence of anemia. The water spinach Ipomoea aquatica is consumed as a vegetable throughout Asia and tolerates high iron concentrations making it an attractive candidate for iron biofortification. L-DOPA is an allelopathic molecule secreted by some legumes. L-DOPA can trigger the expression of Fe deficiency-inducible genes, and could potentially be used as a biostimulant to increase Fe concentration.ResultsL-DOPA significantly affected root growth of water spinach, and triggered a massive accumulation of Fe in roots. Both effects were exacerbated when L-DOPA was dissolved in KOH, which is surprising given that L-DOPA is less stable at high pH. To check whether a higher pH could indeed increase the bioactivity of L-DOPA, we used Arabidopsis thaliana, which grows at lower pH than water spinach, and subjected the plants to L-DOPA treatments at pH 5.5 and pH 6.0, which are both within the optimal range for Arabidopsis nutrition. At pH 6.0, the root growth of Arabidopsis was more strongly inhibited than at pH 5.5. We found that at higher pH, L-DOPA oxidizes to form a melanin precipitate.ConclusionsWe concluded that the oxidation of L-DOPA that we observed upon solubilization in KOH, or in nutrient solutions at slightly higher pH produces melanin-related molecules that are more potent than L-DOPA itself to trigger the primary root growth inhibition, Fe uptake and root Fe accumulation in water spinach and Arabidopsis.

【 授权许可】

CC BY   
© Institute of Plant and Microbial Biology 2023

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