Researchers have determined the signals used by plants to sense and respond to flooding. Understanding how plants adapt to soil flooding can aid in the development of flood-resistant crops. The details are in a paper that was just published in the journal Cell.
Plants use roots to absorb nutrients and water from the ground. This process requires the uptake of oxygen from pore space in the soil. If soil becomes too compacted or waterlogged, the plant may struggle to get enough oxygen. Plants growing in flood conditions have trouble absorbing both water and nutrients without oxygen, leaving the plant with deficiencies and wilted leaves. How plants actually regulate root permeability in these conditions was previously unknown and the focus of the study.
A team of researchers studied Arabidopsis plants, also known as rockcress. The team identified a gene called Hydraulic Conductivity of Root 1 (HCR1). The gene controls the permeability of plant roots and activates a set of genes that respond to low-oxygen (hypoxic) conditions. The gene is switched on when there is potassium present but a lack of oxygen. Once oxygen levels are back to healthy levels, the gene turns off and the roots begin normal uptake of water and nutrients. When HCR1 is activated, the plant recovers quickly after dealing with flooding. If potassium is limited, HCR1 stays inactive and the plant struggles to rehydrate after exposure to waterlogged soil.
The research team has identified the major genetic factors that control water uptake when a plant is exposed to flooding. The gene HCR1 activates when oxygen levels drop in soil, but only when the mineral potassium is also present. The team’s findings will help advance knowledge of plant biology. Understanding how plants sense and respond to stressors, including flood conditions, will also help agronomists. Agronomists can use this new information to develop more resilient crops.
Zaigham Shahzad et al. A potassium-dependent oxygen sensing pathway regulates plant root hydraulics. Cell (2016).