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Click on the thumbnail above to see evidence for multiple high temperature sensing mechanisms in plants. The plant in the top movie was heated at 37 degrees, the one on the bottom was heated at 40 degrees. Note the differences in the timing and location of the responses. This work is described in Kast et al., 2013

Research

Plants are sessile organisms which have to handle extreme temperature fluctuations without moving because they are rooted in the ground. To ensure food security in the next century it will be vital to understand how plants sense and respond to high temperature stress in order to develop crop varieties which can be deployed on a globally warming planet.

The mechanisms which cells use to sense high temperatures are only partially understood. At high temperatures proteins denature and membrane fluidity increases. Both protein misfolding and membrane fluidity changes are used as sensors to induce the heat stress response (HSR), a conserved set of transcriptional changes. The HSR results in the production of heat shock proteins (HSPs) which fundtion to ameliorate the effects of elevated temperatures. Research in the lab focuses on two overlapping interests related to heat stress sensing and responses:

Understanding the cellular thermostat. We are interested in understanding the sensing and signaling pathways cells use to induce the HSR. Although some of the genes involved in temperature sensing (thermostat genes) have been identified it is clear that many components of this sensing mechanism remain to be discovered. We are using a high content genetic screening approach to identify thermostat genes and to characterize the connections among these genes.

Understanding the role of the Arabidopsis BOBBER1 (BOB1) gene in proteostasis. BOB1 encodes a non-canonical small heat shock protein which is required for plant thermotolerance. BOB1 protein has chaperone activity in vitro and we have used a BOB1:GFP fusion to demonstrate that BOB1 localizes to heat shock granules at elevated temperatures. BOB1 is unique among plant small heat shock protein because it is the only one with a demonstrated function in plant developmental patterning. In order to understand how a small heat shock protein affects patterning we are currently identifying and characterizing BOB1 interactors using molecular, biochemical, and genetic approaches with the goal of identifying core cellular pathways which depend on BOB1 function.

Please see our recent publications for more information about this research.

The lab is well equipped to investigate plant development and stress responses using molecular genetics, cell biology, and biochemistry. Facilities in the lab and the department include custom microscopes, a well equipped imaging facility, a modern greenhouse, plant growth chambers, and a full array of molecular biology equipment including a four channel real time PCR machine. Most of the research in the lab is conducted by Swarthmore undergraduates, and we are always looking for motivated new lab members.

Research in the lab has been supported by Swarthmore College, The Friedman Fund, HHMI, and a grant from the NIH.