Expression of Auxin-Related Genes During Dedifferentiation of Mature Embryo in Wheat

To elucidate the mechanism of mature embryo dedifferentiation in wheat (Triticum aestivum L.), the activity of genes in the dedifferentiating embryos of wheat cultivar Yumai 18 was determine using Affymetrix microarray technique. The wheat embryos were cultured on MS medium supplemented with 2 mg L−1 of 2,4-dichlorophenolxyacetic acid (2,4-D) and sampled at 2, 6, 12, 24, and 72 h after inoculation. With the help of online tools at NCBI, DATF, and DRTF websites, 80 auxin-related genes were found to be differentially expressed during embryo dedifferentiation, including 41 up-regulated, 29 down-regulated, and 10 both up- and down-regulated genes. The up-regulated genes were more than the down-regulated ones, especially at 24 h and 72 h after inoculation. These genes were supposed to be involved in several biological processes, such as the transportation, response, induction, synthesis, and degeneration of auxin. The expressions of 7 genes (BG906698, BQ281752, CD454626, CD864552, CD938626, BJ233383, and AY543630) were examined and analyzed using semiquantitative technique. The expression patterns of these genes were consistent with the gene expression profiling obtained by Affymetrix microarray technique. Gene of plasma membrane (PM) H+-ATPase (GenBank accession number: AY543630) was expressed in a high level at 2 h after inoculation, and then decreased to the minimum level at 24 h after inoculation. This result implied that PM H+-ATPase gene might be a trigger for dedifferentiation of mature embryos in wheat.

摘 要利用Affymetrix小麦基因芯片研究了小麦成熟胚在MS+2,4-D (2 mg L−1)培养基上脱分化过程种基因表达变化, 用NCBI、DATF和DRTF等生物信息学相关网站对基因表达信息进行处理, 并针对生长素相关基因的变化情况进行分析。结果表明, 有80个生长素相关基因在小麦成熟胚脱分化过程中的2、6、12、24和72 h等不同时间点, 至少发生了一次有意义的表达变化, 其中41个在整个过程中上调, 29个下调; 10个在不同时点分别表现上调或下调。这些基因涉及到生长素的运输、响应、诱导、合成和降解等多个生物学过程。对BG906698、BQ281752、CD454626、CD864552、CD938626、BJ233383和AY543630基因的半定量RT-PCR验证结果表明, 它们的表达变化与基因芯片的结果基本一致。质膜H+-ATPase基因(AY543630)在2 h时间点即有较高强度表达, 然后下降, 24 h降至最低水平, 表明该基因在小麦成熟胚脱分化的启动中可能有重要作用。