Analysis Of Gene Expression Profiles Of WRKY And BZIP Families Transcri Ption Factor And Their Targets During Dedifferentiation Of Mature Wheat Embryos

Transcription factors play an important role in regulating of genes expression. The quality of dedifferentiation determines the capacity of callus regeneration. Mature embryo is considered to be of the most potential target for genetic transformation, but its transformation efficient is still lower now. To elucidate the mechanism of mature wheat embryo dedifferentiation, expression profile of genes in dedifferentiation was studied by Affymetrix microarray technique in mature embryos of wheat cultivar Yumai 18 cultured on MS medium supplemented with 2,4-dichlorophenolxyacetic acid (2,4-D, 2 mg L?1) at different time points of 2, 6, 12, 24,and 72 h. The results showed that by using the Affymetrix wheat GeneChip including 61127 probe sets, which represented 55085 genes, about 15000 genes of those were happened to have meaningful expression change. The transcription factor families and their target genes with meaningfully changed expression were mainly analyzed. The total amount of 425 genes related to those 24 types of transcription factor families were found to play a role in the process of dedifferentiation of mature wheat embryos. Two types of transcription factor families and their target genes from 42 types of transcription factor families have been done a further analysis. The results were as follows:WRKY family transcription factors and their target genes 7 WRKY family transcription factors and their 28 target genes were studied. According to their expression during the dedifferentiation, WRKY27 and its target gene DFL-1 play roles in the hormone signal transduction during dedifferentiation. WRKY33 and its target genes may have functions in the initiation of dedifferentiation. The tendency of expression change of WRKY2, WRKY3, RKY18 and their target gene PR1 implies that SA signal pathway may take part in differentiation of mature wheat embryos. bZIP family transcription factor and their target genes bZIP protein related to the gene expression of storage protein, light morphogenesis and the formation of organ. bZIP proteins play a role in regulating gene expression of signal transduction. 7 genes of bZIP transcription factors and their 32 target genes were found changes of expression. According to their overall expressions on the chip, all of bZIP transcription factors were down-regulated at the different stages of dedifferentiation. Furthermore, 6 genes were up-regulated by 2-10 times, 11 genes down-regulated by 1-20 times, and 3 genes up- or down-regulated at the different stages of dedifferentiation. bZIP transcription factors were down-regulated in dedifferentiation. This implied that the target protein was negative regulate in dedifferentiation.Semi-quantative RT-PCR technique was used to verify the results of microarray. The expression changes of four genes, coded for WRKY2, CA744619, BJ290016 and BQ170258, were confirmed to be consistent with the results of microarray.