Miller lab

 

Our lab is interested in understanding how plants respond to environmental cues at the molecular and physiological levels and how metabolism and signaling of reactive oxygen species (ROS) impact these responses. We mainly use Arabidopsis thaliana (mutants and transgenic plants) to uncover the roles of ROS in the perception and response to the changes​ in the environment such as elevated temperatures, drought, salinity, excess light, and oxidative stress.
 

Background - Production, and accumulation of ROS induced by changes in the environmental conditions can induce oxidative stress in the plant cells, which can be toxic, causing oxidation of lipids, proteins, DNA, and metabolites. In contrast elevation in ROS level also act as signals that play essential roles in the regulation and maintenance of cellular and physiological functions. All living organisms must tightly regulate the level of ROS molecules such as hydrogen peroxide (H2O2), superoxide radical (O2.-), and singlet oxygen 1O2, to avoid over accumulation on the one hand, but also to avoid having too little of them.  Our challenge is to understand how the plant cells resolve the duality between ROS toxicity and ROS necessity in the redox biology of the plant, under different conditions, growth stages, and tissues. 

The ultimate goal of our research is to apply the newly gained knowledge to improve crop plant's yield production.

Our research is focused on two main aspects:
1. Studying the involvement of the three cytosolic ascorbate peroxidases, APX1, APX2, and APX6,  under favorable condition and during stress.  As H2O2 scavenging enzymes, the cAPXs play key function as both important antioxidants as well as modulators of ROS and redox signaling in the cytosol that affect intra-cellular-, as well as cell-to-cell communication. We have identified the role of cAPXs in seed's and pollen stress tolerance, and in the systemic response of the entire plant to elevated temperatures and high light irradiance. 
2. Identify new ROS-signalling components and study their role in the plant stress response, using functional genetic approaches.

Schematic model showing the impact of ROS metabolism and signaling at the cellular and whole plant level.
The cAPX  at the center of the signaling hub can modulate the ROS signal signature that stimulates specific gene responses, activating stress acclimation programs in distinct tissues and developmental stages