Effects of short-term exposure to elevated atmospheric CO2 on yield, nutritional profile, genetic regulatory pathways, and rhizosphere microbial community of common bean (Phaseolus vulgaris)

Summary

This field trial examined how short-term exposure to elevated atmospheric CO₂ (600 ppm) during pod-filling to maturity affects common bean nutritional quality and soil microbial ecology. Whilst elevated CO₂ increased overall biomass yield, it reduced grain iron and zinc concentrations by 59% and 49% respectively, and decreased phenolic content by up to 41%, with these effects associated with altered expression of nutrient uptake and stress-response genes and shifts in rhizosphere microbial community composition. The findings underscore potential climate change impacts on legume nutritional value and the need for crop improvement strategies to maintain micronutrient adequacy under future eCO₂ conditions.

Regional applicability

The study was conducted under field conditions and provides mechanistic insights relevant to United Kingdom cereal and legume production under projected future atmospheric CO₂ concentrations (around 600 ppm). The findings on CO₂-induced reductions in micronutrient density are particularly relevant to UK food security policy and agricultural adaptation planning, though the specific cultivar, soil type and climate conditions may differ from typical UK growing environments; further validation in UK field conditions would strengthen applicability.

Key measures

Plant and grain biomass yield; grain iron and zinc concentrations; grain phenolic content; expression of genes involved in mineral uptake (FER1, ZIP1, ZIP16), stress response (TCR1, TCR2, HLH54) and symbiosis (NRMAP7, RAM2); relative abundance of bacterial phyla in rhizosphere microbiome

Outcomes reported

The study measured effects of one-month elevated CO₂ (600 ppm) exposure on common bean biomass, grain mineral composition (iron, zinc), phenolic content, gene expression patterns, and rhizosphere microbial community structure during pod filling to maturity under field conditions.

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