Functional Analysis Of Arabidopsis COL2Protein In ABA And NaCl Signaling Pathways

ABA as an important plant hormone affects plant growth and development,including the response to various environmental stresses. Salt stress is one of the mostserious environmental stress for the crop, high salt environment will lead to growthretardation and even failure. The ABA level in the plants increased under stressconditions, and the accumulation of ABA prompted stomatal closure, the geneexpression changes or accumulation of osmotic compatible material in order to bettermeet the needs of plant physiology. CONSTANS (CO)/COLs is a small family ofthe BBX family containing a CCT domain, among them, CO is a key protein in thephotoperiod pathway, mainly regulated by he circadian clock and light, it can directlybind to the downstream gene FT and SOC1result in promoting the plants blossom.CO/COLs is a family of a total of17members in Arabidopsis, among them, COL2isa member of the first group, and the high homology of CO, with two B-boxesdomains and a CCT domain.In this study, we used the wild-type of Arabidopsis col4for experimentalmaterial, used In-Fusion cloning techniques to constructing COL2into a plantexpression vector pEGAD-LUC. Ater the over expression of COL2and col2mutantsidentified, via the phenotype, luminometer detector to detect the protein level, real-time quantitative PCR to analyse the transcription level and subcellular localizationstudies under ABA and NaCl treatments, exploring the function of COL2protein inthe ABA and NaCl signal transduction pathways.The main findings are as follows:(1) Successfully identified COL2overexpression and col2homozygous mutantplants.(2) Under the ABA and NaCl treatments, the use of luminometer microplate luminescence detector detects COL2protein levels upregulated.(3) Under the ABA and NaCl treatments, compared with the wild-type phase,COL2overexpression appears sensitive phenotype, while col2mutant is insensitive.(4) Using real-time quantitative PCR to analyse the COL2transcriptional level,the results show that, COL2gene expression is highest in wild-type Arabidopsisseedlings, the expression of the root is lowest.(5) Through the analysis of gene expression in response to stress, the resultsshow, COL2is a negative regulator of expression through a ABA dependent pathwayin response to stress gene.(6) Construction of the yellow fluorescent protein (YFP) fusion expressionvectors, using subcellular localization technique proved COL2protein is located inthe nucleus and as a nuclear regulatory factors play a role in ABA signal transductionand NaCl process.