Short-Term Responses of Soybean Roots to Individual and Combinatorial Effects of Elevated CO2 and Water Deficit

The 2019 study explored the short-term effects of elevated atmospheric carbon dioxide (E[CO2]) and water deficit on soybean roots, examining changes in gene expression. Elevated CO2 increased photosynthesis, biomass, plant height, and leaf area, and led to the down-regulation of 274 genes, particularly those related to iron transport and secondary metabolism. Water deficit affected 13,555 genes, with a majority being down-regulated and associated with stress response, signaling, and hormone response. The combination of E[CO2] and water deficit resulted in a unique response in 182 genes, with E[CO2] mitigating some of the negative effects of water deficit. Root dry biomass increased under E[CO2] due to more lateral roots, and water use efficiency improved, helping maintain plant water content. The study concluded that E[CO2] can buffer the adverse effects of water deficit on soybean roots and identified specific genes that respond to these environmental factors.