Transcriptome profiling and methyl homeostasis of an Arabidopsis mutant deficient in S-adenosylhomocysteine hydrolase1 (SAHH1)

ABSTRACT: Transcriptome profiling was conducted to detect genes whose expression is significantly changed in an Arabidopsis mutant deficient in S-adenosylhomocysteine hydrolase1 (SAHH1) during early seedling development when mutant phenotypes could be clearly observed. A total of 2,040 differentially expressed genes were identified, representing approximately 6.7% of the 30,385 DNA oligonucleotide targets on the microarray. Among these differential expressed genes, many were mapped to pathways essential to plant growth and development including those of primary, secondary and hormone metabolisms. A significant proportion of up-regulated genes encoded transposable elements which were mapped to the centromeric and pericentromeric regions of the Arabidopsis chromosomes. A number of down-regulated genes were found to be involved in root hair formation, which might have contributed to the root hair defective phenotype of the mutant. Supplement of homocysteine in the growth medium promoted root cell growth and root hair formation in the sahh1 mutant seedlings. Despite SAHH1 deficient, the expression of genes encoding methyltransferase remained largely unchanged in the sahh1 mutant. Bisulfite sequencing analysis of transposons revealed that their sequences were deficient of 5-methylcytosines in the mutant. Analysis of mutant genomic DNA using restriction endonucleases that were unable to cut methylated DNA suggested a genome-wide hypomethylation had occurred. These results indicated that SAHH1 plays a critical role in methyl homeostasis, and its deficiency is a major contributing factor to the change of global gene expression, metabolic pathways and activation of transposons in the sahh1 mutant. transcriptome profiles between wild type and sahh1 mutant at four different seedling stages (1, 4, 7, 10 days) were compared.

ORGANISM(S): Arabidopsis thaliana

SUBMITTER: Zhangjun Fei 

PROVIDER: E-GEOD-35714 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress