Bradyrhizobium arachidis mediated enhancement of (oxy)matrine content in the medicinal legume Sophora flavescens. (2nd February 2021)

• Record Type: Journal Article
• Authors: Wu, Z.Y.; Meng, X.F.; Jiao, Y.S.; Guo, B.L.; Sui, X.H.; Ma, S.J.; Chen, W.F.; Singh, R.P.
• Is Part Of: Letters in applied microbiology. Volume 72:Number 5(2021)
• Page Start: 570
• Page End: 577
• Publication Date: 2021-02-02
• Subjects: active ingredient -- matrine -- medicinal legume -- nitrogen fixation -- oxymatrine -- rhizobium inoculation -- Sophora flavescens Aiton (SFA); Microbiology -- Periodicals; 660.62
• DOI: 10.1111/lam.13453
• Languages: English
• ISSNs: 0266-8254

Abstract

Abstract: Effect of rhizobial inoculation and nitrate application on the content of bioactive compounds in legume plants is an interesting aspect for interactions among microbes, plants and chemical fertilizers, as well as for cultivated practice of legumes. In this study, nitrate (0, 5 and 20 mmol l −1 ) and Bradyrhizobium arachidis strain CCBAU 051107 T were applied, individually or in combination, to the root rhizosphere of the medicinal legume Sophora flavescens Aiton (SFA). Then the plant growth, nodulation and active ingredients including (oxy)matrine of SFA were determined and compared. Rhizobial inoculation alone significantly increased the numbers and fresh weight of root nodules. Nodulation was significantly inhibited due to nitrate (5 and 20 mmol l −1 ). Only oxymatrine was detected in the control plants without rhizobial inoculation and nitrate supplement, while both oxymatrine and matrine were synthesized in plants treated with inoculation of B. arachidis or supplied with nitrate. The content of oxymatrine was the highest in plants inoculated solely with rhizobia and was not significantly altered by additional application of nitrate. Combinations of B. arachidis inoculation and different concentrations of nitrate did not significantly change the concentrations of (oxy)matrine in the plant. In conclusion, sole rhizobial inoculation was the best approach to increase the contents of key active ingredients oxymatrine and matrine in the medicinal legume SFA. Abstract : Significance and impact of the study: Rhizobial inoculation not only improves the growth of legumes but also promotes the synthesis of specific compounds. In this study, we found the content of oxymatrine, the active ingredient of the medicinal legume Sophora flavescens was enriched significantly in roots only due to rhizobial inoculation and without usage of chemical nitrogen compound (nitrate). Our results will advance the application of rhizobial inoculation on medicinal legumes in terms of increasing the content of the active ingredients, improving the production of oxymatrine‐enriched root biomass, and reducing the use of chemical nitrogen fertilizers in a goal of achieving the sustainable agriculture and cultivation.