Proteomic analysis of leaves of different wheat genotypes subjected to PEG 6000 stress and rewatering

Drought is an abiotic stress that strongly influences plant growth, development and productivity. To understand the drought tolerance mechanism at the protein level in wheat, a differential proteomics study was carried out on young spring wheat leaves of different genotypes in PEG-stressed and rewatered, using two-dimensional polyacrylamide gel electrophoresis (2-DE). A 2-DE pattern with high resolution and good reproducibility was obtained after staining with Coomassie brilliant blue G-250. Using PDQuest software, 600 protein spots were clearly identified from the treatment and control groups with isoelectric points ranging from 4.0 to 7.0. Thirty-eight differentially expressed protein spots were MALDI-TOF/TOF-MS fingerprinted using 2-DE gel and 35 spots were identified by search through the NCBInr database using Mascot software. Of 35 proteins, twenty-one proteins changed in abundance after PEG stress, with 15 proteins up-regulated, whereas 6 proteins down-regulated. Twenty four hour after rewatering, there were 5 proteins up-regulated and 9 proteins down-regulated compared to the well-watered control. Twenty-two differentially expressed proteins were detected in Qingchun 38 and 13 proteins in Abbondanza. They were involved in photosynthesis, protein biosynthesis, energy pathway, carbon metabolism, cell defense, oxidation reduction, transportation and signal transduction. Our proteomics results suggested that drought stress significantly affects wheat photosynthesis.