Effects Of Heat Stress On Antioxidative Enzyme System And Protein Expression In Bermudagrass

Heat stress is one of the serious threats to crop production within the scope of the world. Recently, the unknown situation of climate change and global warming has become more and more severe, and so the influence of high temperature stress on crop growth is also more and more common. As a perennial gramineous crop, bermudagrass is one of the most widely used warm-season turfgrasses, and extensively distributed in Europe, the tropical region of Asia and the subtropical zone. However, nowadays, limited information has focused on the heat-tolerance of warm-season turfgrass, especially the comparision of different heat-tolerance between different organs in turfgrass. This study was conducted on antioxidative enzyme system, gene expression and protent expression of bermudagrass under heat stress. The main contents and results were as follows:1. Plants of bermudagrass’Tifdwarf was exposed to heat stress for24d in a growth chamber. Turf quality (TQ). photochemical efficiency (Fv/Fm) and the chlorophyll content of bermudagrass leaves declined under heat stress. Electrolyte leakage (EL) of bermudagrass’s leaves and roots increased under heat stress. The results of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbic acid peroxidase (APX), glutathione reductase (GR), dehydrogenation ascorbic acid reductase (DHAR), single dehydrogenation activity of ascorbic acid reductase (MDHAR) in bermudagrass’s leaves and roots under the different period of high temperature condition indicated that high temperature treatment had a greater impact on roots’activity of antioxidant enzymes than on leaves. The antioxidative enzyme-related gene expression of leaves and roots in bermudagrass showed that no differences in the transcript level of chl Cu/ZnSOD, FeSOD, MnSOD, DHAR and mMDHAR expression were observed in the leaves after24d of heat stress but all of these expression above were suppressed in roots.2. Plants of bermudagrass’Tifdwarf’ was exposed to heat stress for24d in a growth chamber. TQ, Fv/Fm, chlorophyll content and EL of leaves in bermudagrass did not change significantly after1d of heat stress. However, TQ, Fv/Fm and chlorophyll content declined significantly and EL increased significantly after24d heat stress. Total proteins were extracted from0d,1d and24d of heat-treated and control leaves. Compared with treatment of24d heat stress,1d heat stress had little effect on protein expression of bermudagrass, and only part of metabolism and energy related proteins expression changed, such as CBS domain protein, aspartate aminotransferase, ATP synthase, fructose-bisphosphate aldolase, sedoheptulose bisphosphatasel, peptidyl-prolyl cis-trans isomerase and heat shock protein. However, after long-term (24d) heat stress, the significant changes of most proteins took place, especially proteins related to photosynthesis. The photosynthesis-related protein expression decreased significantly, resulting in the severe decline of plant photosynthesis after long-term high temperature. In this study, we also found6sHSP, and their expression increased under heat stress.