Gene Expression Profile And Proteomic Studies On Freeze Stress In Wheat Plants At Anther Connective Tissue Formation Phase Of Spike Development Stage

In the present study, a common wheat cultivar Yumai34was selected tobe suffered from–5°C freeze stress. And then, in order to explor the molecularmechanism on spring freeze-stress in wheat plants, the gene expression profile andproteomics after1and3days of freeze-stress in leaves of wheat plants at antherconnective tissue formation phase of spike development were studied by cDNAmicroarray and two-dimensional electrophoresis (2-DE). The main results were asfollow.1The rates of relative electrolyte leakage of Five common wheat cultivars sufferedfrom5°C freeze-stress at anther connective tissue formation phase of spikedevelopment had no significant difference. It indicated that the susceptibility to springfreeze-stress had no significant difference in different wheat cultivars at the samespike developmental stage. The observed result on phenotype and microexaminationon young spikes demonstrated that before the spikes emerge from leaf sheath, leavescould be more easily injured by freeze-stress than young spikes within the leaf sheath.2A global transcriptional profile was created using the Affymetrix Wheat GeneChipmicroarray for one wheat cultivar (Yumai34) under5°C freeze stress after1and3days. After1and3days of freeze stress,600genes that were previously annotated asshowing changes in expression of at least than two-fold were measured at one or bothof the time points. After further analysis, we found99genes whose expression levelschanged at least eight-fold after1or3days of freeze stress. These genes encoded anice recrystallization protein, cold-related proteins, CBF transcription factors,calcium-dependent protein kinases, Na+/H+antiporters, aquaporins, and manymetabolic enzymes. The results of this study were compared with those of a previousstudy on the sub-freeze hardening response in wheat and spring freeze stress in barley.Many genes, including those encoding WCOR413, LEA, glycine-rich RNA-bindingprotein, ferritin, aquaporin2, and a pathogen-induced protein, showed similar expression levels in these studies. It indicated that these genes play important roles infreeze-stress response in higher plants.3Following three-day exposure to–5oC simulated spring freeze stress, wheat plantsat anther connective tissue formation phase of spike development were analysedfreeze-stress responsive proteins in leaves at1and3days after following freeze-stressexposure, using two-dimensional electrophoresis and matrix-assisted laserdesorption/ionisation time-of-flight mass spectrometry. Our results indicate that out of75protein spots successfully identified under freeze-stress conditions52spots wereupregulated and18were downregulated. These spring freeze-stress responsiveproteins were involved in signal transduction (4spots),stress/defence/detoxification(17spots), protein metabolism (i.e. translation,processing, and degradation)(13spots), photosynthesis(11spots), amino acidmetabolism(5spots), carbohydrate metabolism(3spots), and energy pathways(1spots), and may therefore be functionally relevant for many biological processes. Theenhanced accumulation of signal transduction proteins such as a C2H2zinc fingerprotein, stress/defence/detoxification proteins including LEA-related COR protein,disease resistance proteins, Cu/Zn superoxide dismutase, and two ascorbateperoxidases may play crucial roles in the mechanisms of response to spring freezestress in wheat plants.4Most of genes changed at transcriptional level and proteins changed at proteinabundance were inconsistently afrer comparation on the results between transcriptomeand proteome. Only4proteins/gens emerged in transcriptome and proteome at thesame time. Four proteins/gens included two S-like RNases, a Cold-responsiveLEA/RAB-related COR protein and a Cu/Zn superoxide dismutase. Theseproteins/genes all involved in defense reaction in wheat plants.