Abstract:

The quality of dedifferentiation determines the capacity of callus regeneration. Mature embryo is considered to be of the most potential for genetic transformation, but its transformation efficiency is still lower now.To elucidate the mechanism of mature wheat embryo dedifferentiation, we studied the expression profile of genes in dedifferentiation using Affymetrix microarray technique in mature embryos of wheat cultivar Yumai 18 cultured on MS medium supplemented with 2 mg L^-1 of 2,4-dichlorophenolxyacetic acid (2,4-D) at different time points of 2, 6, 12, 24, and 72 h. Using online tools at NCBI, DATF, and DRTF websites, 80 auxin-related genes changed at least at one time point were detected with the 41 up-regulated and 29 down-regulated during the whole period. The remained 10 genes showed up-regulation or down-regulation at different time points. Up-regulated genes were more than down-regulated genes, especially at 24 h and 72 h points. These genes were involved in several biological processes, such as transportation, response, induction, synthesis, and degeneration of auxin. Using semi-quantative RT-PCR technique, the expression changes of seven genes, coded as BG906698, BQ281752, CD454626, CD864552, CD938626, BJ233383, and AY543630, were confirmed to be consistent with the result by microarray. Gene of plasma membrane (PM) H⁺-ATPase (GenBank accession number: AY543630) expressed at a high level at the 2 h time point, and then decreased gradually till the minimum at the 24 h time point. This result implied that PM H⁺-ATPase gene might be a trigger in dedifferentiation of mature embryo in wheat.

Key words: Auxin-related gene, Dedifferentiation of mature embryo, wheat, Plasma membrane H⁺-ATPase gene, Microarray