Comparative Proteome Analysis Of Zoysiagrass Matrella (L.) Merr. In Response To Temperature Stress

Cold and heat are the most important factors of abiotic stresses which significantly affect plant growth and its geographical distribution. The systematic proteome approaches have been adopted to study the molecular mechanism of turfgrass plants in responses to temperature stress and, to discover temperature responsive proteins, which paved the way for improving the resistance of the turfgrass to temperature stress. In this paper, the warm season turfgrass, Zoysiagrass matrella (L.) merr., has been studied using two-dimensional gel electrophoresis(2-DE), mass spectrometry(MS), and bioinformatics analyses to explore the differentially expressed proteins of the turfgrass under low temperature(LT) and high temperature(HT) treatments, in addition, to further understand the tolerance of the turgrass in responses to different gradient temperature stresses.Zoysiagrass matrella (L.) merr. plants were treated at 5℃for 24 h and 48h, 40℃for 24h and 48h, 5℃, 10℃, 20℃, 30℃, 40℃for 48h respectively. 30℃treatment was the optimal condition for the turfgrass growth and used as control for the comparison analysis of different treatments. We applied differential proteomics to compare the leaf proteome of the temperature-treated samples to that of control. The result indicated that 35 proteins significantly changed as a consequence of temperature treatment. Of these, 26 proteins were identified in the aid of Q-TOF MS and bioinformatics. The results were summarized as follows:(1) After 24 and 48h of LT(5℃), 15 proteins were down-regulated and 11 were up-regulated. The study showed that 18 proteins were successfully identified by MS, of which 4 proteins were ribulose bisphosphate carboxylase large subunit. 3 proteins identified by MS were novel cold-responsive proteins, including Isoflavone synthase, Peptidase , and ZLL/PNH homologous protein. The identified proteins were involved in photosynthesis, energy metabolism, signal transduction, reactive oxygen species scavenging, and protein processing.(2) There were 17 up-regulated and 5 down-regulated leaf proteins in Zoysiagrass matrella (L.) merr. plants treated at 40℃for 24 and 48h. Mass spectrometry analysis led to the identification of 15 proteins. These proteins may be classified into 4 functional categories, such as, 8 proteins involved in carbohydrate metabolism and energy metabolism , 2 proteins involved in antioxidation reaction metabolism, 4 proteins involved in protein metabolism, and 2 proteins involved in other metabolism pathways.(3) 27 proteins were differentially expressed during the prescribed temperature gradients by using 2-DE analysis , of which 17 proteins were identified by MS and database searching, which associated with energy metabolism, cell defense, protein synthesis and processing, and cytoskeleton stability.Accordingly, the resistance of Zoysiagrass matrella (L.) merr. to temperature stress could be manifested in several aspects: 1) the activities of carbon assimilation enzyme were promoted, 2) the enzymes involved in the signal transduction were accumulated, 3) the activities of the enzyme associated with reactive oxygen species scavenging were increased, 4) protein synthesis and process were accelerated. We also found that many resistance-related enzymes identified were up-regulated to a greater extent in HT than in LT, indicating that the present results are consistent with the physiological properties of the warm season turfgrass, Zoysiagrass matrella (L.) merr..