Temperature stress poses a unique and escalating problem to plants since they are immobile captives of the environment. Plants, like all other organisms, respond to increasing temperature by the specific expression of heat shock proteins. These proteins are essential for the plant to mount a tolerance response to many stresses including higher temperatures. However the specific functions of these proteins in stress tolerance is largely unknown. Preliminary experiments have demonstrated a role for one specific and prominent heat shock protein, Hsp17.7, in thermotolerance, by using antisense technology to decrease the expression of this protein. The proposed experiments will investigate why the plants expressing an antisense version of Hspl7.7 mRNA are less thermotolerant and should provide insight into the overall process of plant thermotolerance. Antisense Hspl7.7 plants show dramatic decreases in the levels of Hspl7.7 as well as other non-related Hsps. The underlying molecular mechanisms by which this occurs will be addressed by quantitative analysis of mRNA and protein levels using gene specific probes and specific antibodies. The analysis will focus on the processes of transcription, translation and protein processing and turnover in transgenic and control cells. In addition, the potential chaperone function of Hsp17.7 will be assessed using standard assays.
