Effects Of Enhanced UV-B Radiation On The Profilin-1 Localization Of Arabidopsis Thaliana

Since the hole in the ozone layer was discovered over Antarctica,the UV-B radiation reaching the ground has been enhanced,not only in the polar regions,but also in other parts of the world that the intensity of UV-B radiation is enhanced in the solar radiation.UV-B radiation has many effects on plant development,morphology and physiology.Therefore,it is a great scientific significance and application prospect to explore the effects of UV-B radiation on plants.Profilin is an abundant,ubiquitous,small actin-binding protein,which is composed of3 alpha helices and 7 beta folds and interacted with poly-L-proline(PLP)and phosphoinositides,playing an important role in the regulation of actin polymerization.Plants have several genes encoding highly divergent profilin isoforms which may have different characteristics.For example,Arabidopsis has an ancient and highly divergent multigene family encoding five distinct profilin isoforms.Among the Arabidopsis Profilin family,PRF1 is constitutively and strongly expressed in all vegetative tissues at various stages of development.In order to study the mechanism of physiological response to UV-B(10.08 KJ/m2/d)radiation to Arabidopsis thaliana,we constructed the fusion gene with GFP tag,and then transformed the fusion gene into Arabidopsis thaliana,finaly,we successfully obtained GFP:PRF1 fusion protein transgenic plants.GFP:PRF1 was studied by two methods of transient expression.On the one hand,it was proved that the vector of the fusion protein was successfully constructed.On the other hand,the subcellular localization of PRF1 in2 two transient expression systems was obtained indirectly.The results showed that the green fluorscence of the fusion protein could be observed after the PRF1 gene was transferred into Arabidopsis protoplasts and tobacco epidermal cells.The fusion protein was localized in the cytoplasm and peripheral organelles of tobacco epidermal cells,and was expressed in the nucleus and cytoplasm of Arabidopsis protoplasts.The localization of PRF1 protein is different in two different transient expression systems,which may be related to homologous or heterologous expression of plant properties.After homozygous Arabidopsis transgenic plants were obtained,the phenotype of transgenic and wild type plants were compared and found that the root length and plant light were not significantly different.Then,the expression of GFP:PRF1 fusion protein in different tissues of Arabidopsis thaliana was observed,It was found that PRF1 was expressed in all tissues of plants,it is further demonstrated that recombinant vectors can be expressed in Arabidopsis thaliana.From the previous results,it was found that PRF1 was distributed in the Arabidopsis root tip,in order to explore the correation between PRF1 and chromosomes during UV-B treatment,DAPI was used to laber the root tip of Arabidopsis and found that when the transgenic Arabidopsis plants were treated with UV-B,the chromosomes in the apical meristem cells showed abnormal division,and PRF1 was also observed to be distributed with chromosomal abnormalities.And whether this phenomenon is due to overexpression of PRF1 to affect the behavior of chromosomes? At the same time,the chromosomes of wild type and transgenic plants were labeled by DAPI,found that there in no abnormal chromosome division,indicating that the abnormal chromosome phenomenon is not caused by overexpression of PRF1,it was also found that PRF1 was similar to the distribution of chromosomes.PRF1 was mainly accumulated in the nucleus during interphase,and PRF1 was evenly distributed in the cytoplasm when the cells began to enter the anaphase.