Study On The Function Of Brassica Campestris BrICE1 And BrICE2 Genes In Plant Cold Signal Transduction

Temperature is an important environmental factor that determines the quality and yield of crops.Our country will cause serious economic losses every year due to cold damage.Rapeseed is the main economic and oil crop in my country,and understanding its antifreeze mechanism and improving its antifreeze ability through genetic engineering means are of great significance for increasing Rapeseed yield and improving Rapeseed quality.The ICE genes belongs to the bHLH family and plays an important role in plant cold signal response.In this experiment,BrICE1 and BrICE2 of Rapeseed were cloned from variety"Tianyou 8"based on the information obtained according homologous sequence alignment in the Rapeseed database,taking AtICE1and AtICE2 as the reference sequences.Their functions were studied through in genetic modified Arabidopsis,the main results are as follows:1.The BrICE1 and BrICE2 genes contain typical functional domains and conserved motifs of Arabidopsis ICE RT-PCR identification results indicate that the Rapeseed ICE genes are stably expressed in Arabidopsis.2.Under cold stress,the survival rates of transgenic plants of AtICE1?AtICE2?BrICE1 and BrICE2 are higher than that of wild type,indicating that the cold resistance of genetic modified Arabidopsis is stronger than that of wild type.3.Tobacco transient results show that AtICE1?AtICE2?BrICE1 and BrICE2 are all located in the nucleus.GUS staining results show that they are expressed in plant leaves,hypocotyls and roots,and the expressions in hypocotyls and leaves are stronger than in root.4.The relative conductivity and MDA of genetic modified Arabidopsis under cold stress are lower than that of wild type,indicating that the transgenic plants have less damage to the membrane than wild type.Under cold stress,the content of H₂O₂ and O₂×^-in enetic modified Arabidopsis are lower than that of wild type,and the content of antioxidant enzymes is higher than that of wild type,indicating thatgenetic modified Arabidopsis have a more efficient ROS removal system.More proline,soluble sugar and total chlorophyll accumulate in genetic modified Arabidopsis to participate in the cold resistance.5.The results of real-time fluorescence quantitative PCR show that the expression of cold response genes in genetic modified Arabidopsis was up-regulated under cold stress,indicating that the Rapeseed ICE gene is involved in the regulation of cold response-related genes.