Proteomic Research Of Rice Root Tip Plasma Membrane Under Salt Stress With BN/SDS-PAGE

A highly purified plasma membrane fraction from popular japonica rice Xudao3(pryza sativa) root tips were isolated using two phase partition system, then we studied the change of proteins from rice root tip plasma membrane with BN/SDS-PAGE, The stress response proteins in plasma membrane were identified by LC-MS/MS. Furthermore, the identified proteins were confirmed on mRNA level by RT-PCR analysis under salt stress. The main contents are as follow:1Change of proteins from rice root tip plasma membrane with BN/SDS-PAGEThe root growth of rice seedling was significantly inhibited by the150mM NaCl stress. A highly purified plasma membrane fraction was isolated using an aqueous Dextran-Polyethylene Glycol two phase partition system. Solubilized plasma membrane fractions were then analyzed by BN/SDS-PAGE。Comparative analysis between three independent biological replicates revealed that the expressions of18proteins were changed after salt treatment, of which7were down-regulated(Major intrinsic protein, putative aquaporin, Cytosolic malate dehydrogenase, cytochrome P450, H+-transporting ATPase, aldolase C-1and Enolase)and4were up-regulated(14-3-3protein, Glutathione S-transferase Ⅱ, Haem peroxidase, Sucrose synthase2)respectively. Mass spectrometry analysis indicated that15of them were membrane associated proteins, and only3spots represented the contaminated proteins from other organelles. Most of them were involved in important physiological processes.2Expression change of proteins from rice root tip plasma membrane under salt stress on mRNA level We further studied the transcription changes of proteins from rice root tip plasma membrane under salt stress. The research on mRNA levels for the proteins identified by BN/SDS-PAGE was carried out by RT-PCR. It was found that most of the down-regulated proteins were consistent between on the level of transcription and5of the up-regulated proteins were consistent between on the level of transcription. But4proteins were not as that. These results suggested that the changes on transcriptional level did not completely reflect the changes on translational level, which probably caused by the modification and stabilization of mRNA and protein.