Regulation Of Exogenous Substances On Wheat Under High Temperature And Light Stresses And Cloning Of Chloroplast Protease Gene FtsH

As an important crop of China, Wheat (Tritivum aestivum, L) affectsfood security directly as well as the development of national economy. The outputlevel is limited to the formation of its grain in the process of wheat growth, and thephotosynthesis is the key to the formation of crop production, which requires thegrowth and process of wheat with appropriate light and temperature. Slanted towardcool environment, the appropriate growth temperature of wheat crops is15-20℃.When the average temperature of the grain filling period above15℃willnot beconducive to the formation of grain weight. In middle and later periods of the wheatgrowth often suffer the double stress of high temperature and strong light. In recentyears, with the changing of temperature, the increasing of double stress make moredestruction of the photosynthetic organization of wheat plants and directly effect theformation of grain and finally wheat production are disrupted. In this experiment, awheat chloroplast FtsH-like fragment was cloned by using bioinformatics analysisapproach, and the effect to both wheat chloroplast antioxidant enzyme activity andmembrane stability caused by different concentrations of DPI and SA, GB exogenousinduction under high temperature and light was studied, which aims to confirm theexistence of wheat FtsH protease and explore the response to high temperature andlight stress caused by the osmotic regulation substances of DPI, DPI and SA, GB.Fundamental study was provide for the further research of wheat chloroplast FtsHprotease gene transcription and expression and under high temperature stress damagedD1protein degradation and PSII function repair relations, as well as for theapplication of regulators in manufacture practice.Two wheat variety “Aikang58and Chinese spring” as materials, the experimentswere carried out in Henan Agricultural University. Wheat seeds were planted in potsin artificial climate chamber.Test material is given priority to with wheat seedlingstage four leaf, water spray for comparison, respectively, with different concentrationof DPI (0.1mmol·L-1、1.0mmol·L-1、10mmol·L-1) and the DPI with0.3mmol·L-1SA, 1.0mmol·L-1GB pretreatment of wheat leaves together, and then, different sowingprocessing.The main results were as follows:1. DPI can improve the stomatal opening and closing and activity of antioxidantenzymes of wheat leaf under high temperature and strong light stressesHigh temperature and strong light stresses make wheat leaf stomatal closure, inorder to reduce water evaporation, is the stress of plants to adversity stressprotection.In addition, wheat under high temperature and strong light stresssuperoxide dismutase (SOD), ascorbic acid peroxidase (APX) and catalase (CAT)activity of antioxidant enzymes affected are reduced.DPI on wheat leaf afterprocessing, the pores open, a series of antioxidant enzyme activity also varyingdegrees of increase significantly.That participated in the wheat stomatal movementand antioxidant enzyme NADPH oxidase activity process, DPI can improve the hightemperature and strong light stress on wheat.2. The regulatory effects of salicylic acid and glycinebetaine on activities ofantioxidant enzymes and function of cell membranes of wheat leaves under hightemperature and irradiationUnder high temperature and irradiation, SOD, APX and CAT activity ofantioxidant enzymes decreased, MDA, H2O2content increases, the O2．-production rateand relative electric conductivity changes.And of the wheat plant induced by SA, GBSOD, APX and CAT activity of antioxidant enzymes were different degree rise,reduce MDA, H2O2content, O2．-producing rate and relative conductivity.SA and DPIcommon treatment effect is better than the effect of spraying GB and DPI, illustratethe SA for the antioxidant enzyme activity of wheat under high temperature and lightcan play a better adjust osmosis, help maintain cell membrane stability under hightemperature and light, reducing oxidative damage to produce wheat, enhance plantresistance.3. DPI for SA, GB under high temperature and strong light stress induced effect haveweakenedUnder high temperature and strong light stress, DPI processing wheat leafstomatal opening, and the SA, GB spraying DPI after induction of plant stomata thedecrease of the strength has to a certain extent, shows that DPI induction of SA, GBregulation has certain influence.Although the plant induced by SA, GB SOD, APXand CAT activity of antioxidant enzymes was increased, the MDA, H2O2contentdecreases, O2．-producing rate and relative conductivity.But with different DPI concentrations of SA, GB common wheat processing after a series of activities ofantioxidant enzymes was not uniform, the stability of wheat under high temperatureand strong light stress membrane is different.That under high temperature and stronglight DPI for SA, GB osmotic regulation have weakened, and there is a link betweenthis and DPI concentration.4. Cloning of Wheat chloroplast protease gene FtsHUsing bioinformatics to blast the4protein sequences of Arabidopsis AtFtsH1,AtFtsH2, AtFtsH5and AtFtsH8and search the highly conserved homologous regionsto design degenerated primers to amplified PCR products use DNA as template,chloroplast protease gene FtsH was identified to be exist in wheat by getting afragment of837bp. Meanwhile a fragment of617bp was derived from Chinese Spring,analysis by phylogenetic showed that it has a closer relationship with ArabidopsisAtFtsH7, AtFtsH9.