Decoding plant heat stress signal transduction by proteomics
Xu Wang, Baowen Zhang, Daye Sun and Wenqiang Tang*

Collage of Life Sciences, Hebei Normal University, Shijiazhuang 050016
* Corresponding author: Tel: 0311-80787547; Email: tangwq@gmail.com

Abstract
Temperatures above the optimum are sensed as heat stress (HS) by all living organisms. When exposed to high temperature, plants have evolved sophisticated mechanisms to maintain cellular homeostasis and minimize cell damage. Although genetic studies in model systems such as Arabidopsis have identified several key components of heat signaling pathway, our knowledge about how plant sense environmental temperature change (the temperature sensor and the downstream heat signal transduction pathways) is still very limited. The recent developed proteomic technologies have now emerged as an important tool in identifying new signaling transduction proteins. Compared with traditional genetic studies, which rely on phenotypes caused by altering gene activity, proteomics not only identifies protein’s function, but also reveals their mechanisms of function and regulation, such as posttranslational modifications and protein-protein interaction. Using the two-dimensional difference gel eletrophoresis (2-D DIGE) technology, we analyzed the proteomic changes in seven-day-old rice and Arabidopsis seedlings which had been exposed to high temperatures (42 degree for rice and 37 degree for Arabidopsis) for 1 min and 5 min. By MS/MS, we have identified 65 early heat responsive proteins (EHRPs) from Arabidopsis seedlings and 125 EHRPs from rice seedlings. Among these proteins, 14 proteins showed similar pattern of abundance change in both rice and Arabidopsis after heat shock treatment, suggesting the functions of these proteins in heat stress response are conserved in planta. While none of the previous known heat signal transduction proteins was identified from our study, the phosphorylation of a few proteins was found undergo rapid changes after heat treatment. By yeast two hybrid screening, we have identified an EHRP interacting protein kinase. Futher studies will reveal a new early heat responsive pathway in heat stress signaling and plant growth regulation.

Key Words: Heat Stress, Signal Transduction, Proteomics, 2D-DIGE