Research On Expression Of Autotetraploid Arabidopsis Homologous Recombination Genes And Bioinformatic Analysis Of Their Encoding Protein

Polyploidization is one of the main ways of angiosperm evolution. Comparedwith the parental diploid，polyploid plants occur some changes，such as the size ofinflorescence, seeds and stomatal cells increasing，and the increase of certainmetabolites，and they also show some resistance, infertility and great resistance，thesechanges may create enormous social and economic value. Previous studies haveshown that in the initial formation of polyploid species and the evolutionary processpolyploidization go with the doubling, namely through DNA elimination、genesilencing and chromosomal rearrangements, etc, forming genome reconstruction, thuschanging the certain genes in the original genome linkage or genetic model to inducegenetic and epigenetic changes.Freshmen polyploid cells not only exhibit newmolecular genetic features and also a number of specific changes in the level of geneexpression and other aspects.Meiosis is the key of the sexual reproduction species generational, and thehomologous recombination during meiosis is the source of genetic variation. Thecourse of homologous chromosome pairing, synapsis and recombination processoccurs in the meiosis Ⅰthat consists of a series of gene expression and jointcoordination completed according to a certain time and space,and polyploidizationinducing the changes of genetic and epigenetic lead to that these processes have beenaffected, but the specific mechanism is unclear induced.Thus, we use the advantages of the model plant Arabidopsis thalianadevelopmental and reproductive, first synthesizing tetraploid plants. In epigenetics,the determination of tetraploid Arabidopsis genome-wide changes in methylation byhigh performance liquid chromatography (HPLC)is lower; and then combined withthe known meiosis-related genes, we in Arabidopsis Information database (TAIR)selecte five genes(ASY1, DMC1, MSH4, MRE11, SPO11-1) that play a key role in theprocess of the federation, pairing and recombination and using real-time quantitativePCR, we analysis the changes in their relative expression levels in different ploidy and it showe improved. With protein bioinformatics, make the use of relevantsoftware to analysis structure and function of these five genes encoding proteins.Our main results are exhibited as follows:（1）Get tetraploidArabidopsis.Treat diploid Ws type Arabidopsis with colchicines. After a series of screening,the results show that when the concentration of colchicine was0.3%and theprocessing time was2h, it is the best inducing that the induction rate of22%is, so weused in the experiment the concentration of0.3%colchicine and handlingtime of2has a combinations, ultimately we get tetraploid Arabidopsis thaliana.（2）Preliminary study on the relationship between DNA methylation degree andrelated gene expression levels in the autopolyploid.Measured by HPLC tetraploid Arabidopsis genome-wide DNA methylationlevels is decreased, according to the results of real-time PCR detection method weknown the homologous recombination gene expression levels in autopolyploid to acertain extent exhibit improved phenomenon. That consistent with the experimentalconclusions to some extent. This study suggests that the reducing of thewhole-genome DNA methylation associate with the improved level of homologousrecombination gene expression in the presence. But the specific mechanism existsbetween the two remains to be studied.