Root-exuded specialized metabolites reduce arsenic toxicity in maize
Veronica Caggìa1,2, Jan Wälchli2, Gabriel Deslandes-Hérold1
1Institute of Plant Sciences, University of Bern, Bern CH-3013, Switzerland.
Summary
Plants release specialized metabolites like benzoxazinoids to protect against arsenic toxicity. This improves crop performance in contaminated soils and benefits future generations through soil feedback.
Area of Science:
- Plant biology
- Environmental science
- Agroecology
Background:
- Plants release specialized metabolites to modify their environment.
- The role of these metabolites in protecting plants from toxic trace elements is not fully understood.
- Benzoxazinoids are specialized metabolites released by cereals into the soil.
Purpose of the Study:
- To evaluate the protective effect of benzoxazinoids against arsenic toxicity in maize.
- To investigate the mechanisms underlying this protection, including soil-mediated processes.
- To assess the impact of benzoxazinoids on crop performance and plant-soil feedback.
Main Methods:
- Comparison of benzoxazinoid-producing maize with benzoxazinoid-deficient mutants in arsenic-contaminated soils (greenhouse and field).
- Application of exogenous benzoxazinoids to soil to assess their protective effect.
- Measurement of soil arsenate levels and total arsenic in plant roots.
- Evaluation of plant-soil feedback effects on subsequent crop generations.
Main Results:
- Benzoxazinoid-producing maize showed improved performance in arsenic-contaminated soils compared to mutants.
- Soil application of benzoxazinoids restored the protective effect.
- Arsenate levels in soil and arsenic accumulation in roots were reduced in the presence of benzoxazinoids.
- The protective effect persisted to the next crop generation, indicating positive plant-soil feedback.
Conclusions:
- Exuded specialized metabolites, such as benzoxazinoids, can protect plants against toxic trace elements like arsenic.
- The protection is primarily soil-mediated, involving alterations in soil arsenic speciation and reduced root uptake.
- Plant-derived metabolites can enhance crop resilience and stabilize productivity in polluted agroecosystems through plant-soil feedback mechanisms.
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