Poster: Temperature Responses

Abs # 193: Functional analysis of the genes encoding cold-acclimation-responsive plasma membrane proteins in Arabidopsis thaliana

Presenter:	Tominaga, Yoko , t0minaga@iwate-u.ac.jp
Authors	Tominaga, Yoko  (B)   Nakagawara, Chihaya  (A)   Kawamura, Yukio  (C)   Uemura, Matsuo  (A)
Affiliations:	(A): Cryobiosystem Research Center, Iwate University (B): BRAIN, Tokyo, Japan (C): Cell Biology and Molecular Genetics, University of Maryland

Many studies have shown that gene expression is considerably altered during cold acclimation in various plant species, and a number of genes responsive to low temperature have been identified. We have been focusing on cold-acclimation-induced alterations of proteins associated with the plasma membrane because the destabilization of the plasma membrane is thought to be the primary cause of freezing injury. We succeeded in identifying a number of the altered proteins associated with Arabidopsis plasma membrane during cold acclimation using peptide mass finger printing method coupled with MALDI-TOF MS (Kawamura & Uemura, Plant Biology 2002). Here, we report the findings on the structural, expressional and functional analyses of genes that encode the cold-acclimation-responsive plasma membrane proteins in Arabidopsis. Using the Arabidopsis genome database, the genes encoding those plasma membrane proteins were isolated. The levels of the transcripts of several genes increased during the first day of cold acclimation, indicating that the accumulation of the proteins is regulated by gene expression. Survey of the genome sequence database revealed that the promoter region of several genes contains various low-temperature-responsive, dehydration-responsive, and/or ABA-responsive elements, also suggesting that the genes can be eventually induced by cold acclimation. To determine their effects on the freezing tolerance and freeze-induced lesions of Arabidopsis in planta, transgenic plants that constitutively overexpress the genes encoding the plasma membrane proteins that increased at the early stage of cold acclimation have been constructed, and the freezing test of whole plants and excised leaves is in progress. (This study was, in part, supported by PROBRAIN, Japan.)