Function Analysis Of CUC2 In Arabidopsis Leaf Development

Leaves are the main organs for photosynthesis in plants,its shape and size will affect the economic and ornamental value of plants directly.The morphology of plant leaf margins is regulated by many factors,among which CUC2,MIR164,PIN1 and Auxin play an important role in the regulation of leaf serration development.EMBRYONIC FLOWER 2(EMF2),VERNALIZATION 2(VRN2),CLURLY LEAF(CLF)and SWINGER(SWN)are important componetents of Polycomb Repressive Complex 2(PRC2).This study used Arabidopsis thaliana as experimental materials to reveal the function of epigenetic regulator PcG(Polycomb Group)in regulating leaf serration development and the role of ectopic CUC2 in regulating cell division in Arabidopsis leaves.The main experimental content and results are as follows:1 The Analysis of the leaf serration degree of Arabidopsis PcG mutant clf-28 swn-7 CLF::CLF-GR(iCLF)showed that the serration degree of iCLF is bigger than that of wild type Col-0.Real time quantitative PCR results showed that the expression levels of CUC2,CUC3,MIR164B and MIR164C in iCLF were significantly increased.By measuring and analyzing the influourence intensity of CUC2::Venus in WT and ev,it was concluded that CUC2 is expressed in the sinus region at the early stage of leaf development,and the influourence intensity of CUC2::Venus was significantly higher in ev than La-0.2 Chromatin immunoprecipitation results showed that CLF could bind to CUC2,in iCLF and ev,the level of H3K27me3 at CUC2 locus was significantly reduced,indicating that CUC2 is a target of PcG.By introducing CUC2 mutation to PcG mutants iCLF and ev led to the reduction or disappearance of leaf serration,suggesting that PcG is involved in the development of leaf serration by regulating the level of H3K27me3 at CUC2 locus.3 The leaf area and width of PcG mutants iCLF and ev are significantly smaller than that of wild type.According to the analysis of cell number and size,it can be seen that the decrease in leaf width is related to the number of cells,and the size of the cells does not change.4 In the continuously DEX induced 35S::CUC2-GR,the leaf width,callus weight,and root tip cell divisions were significantly reduced compared to those that had not been induced.And the decrease in leaf width was related to the number of cells,but the cell size did not change.qRT-PCR results showed that in the continuously induced 35S::CUC2-GR,the expression level of cell division related gene KN decreased,indicating that the ectopic expression of CUC2 can inhibit cell division.