The Defensive Role of Endogenous H2 S in Brassica rapa against Mercury-Selenium Combined Stress

Abstract

Plants are always exposed to the environment, polluted by multiple trace elements. Hydrogen sulfide (H2 S), an endogenous gaseous transmitter in plant cells, can help plant combat single elements with excess concentration. Until now, little has been known about the regulatory role of H2 S in response to combined stress of multiple elements. Here we found that combined exposure of mercury (Hg) and selenium (Se) triggered endogenous H2 S signal in the roots of Brasscia rapa. However, neither Hg nor Se alone worked on it. In roots upon Hg + Se exposure, the defensive role of endogenous H2 S was associated to the decrease in reactive oxygen species (ROS) level, followed by alleviating cell death and recovering root growth. Such findings extend our knowledge of plant H2 S in response to multiple stress conditions.