ENO2 knock-out mutants in Arabidopsis modify the regulation of the gene expression response to NaCl stress

There is a growing awareness that some dual-function enzymes may provide a directly evidence that metabolism could feed into the regulation of gene expression via metabolic enzymes. However, the mechanism by which metabolic enzymes control gene expression to optimize plant stress responses remains largely unknown in Arabidopsis thaliana. LOS2/ENO2 is a bifunctional gene transcribed a functional RNA that translates a full-length version of the ENO2 protein and a truncated version of the MBP-1 protein. Here, we report that eno2 negatively regulates plant tolerance to salinity stress. NaCl treatment caused the death of the mutant eno2/eno2 homozygote earlier than the wild type (WT) Arabidopsis. To understand the mechanism by which the mutant eno2 had a lower NaCl tolerance, an analysis of the expressed sequence tag (EST) dataset from the WT and mutant eno2 Arabidopsis was conducted. Firstly, the most identified up- and down-regulated genes are senescence-associated gene 12 (SAG12) and isochorismate mutase-related gene, which are associated with salicylic acid (SA) inducible plant senescence and endogenous SA synthesis, respectively. Secondly, the differentially regulated by salt stress genes in mutant eno2 are largely enriched Gene Ontology(GO) terms associated with various kinds of response to stimulations. Thirdly, in the Kyoto Encyclopedia of Genes and Genomes (KEGG) mapping, we find that knocking out ENO2-influenced genes were most enriched into metabolite synthesis with extra plant-pathogen interaction pathway and plant hormone signal transduction pathway. Briefly, with the translation shifting function, LOS2/ENO2 not only influenced the genes involved in SA synthesis and transduction, but also influenced genes that participate in metabolite synthesis in cytoplasm and gene expression variation in nuclear under salt stress.