Abstract
Plant cells respond to the environmental stress through reversible posttranslational modifications of important signal molecules. The dynamic glycosylation of serine or threonine by O-linked β-N-acetylglucosamine (O-GlcNAc) is critical to many cellular response and reciprocal to O-phosphorylation. In Arabidopsis, SPINDLY (SPY) gene encodes an O-GlcNAc transferase (OGT), which was originally identified as a negative regulator in GA signaling. In this study, we found that spy mutants are more tolerant to osmotic stress, such as high salinity and dehydration. SPY gene expression is specifically drought inducible. Transcriptome analysis of spy-3 mutant discovered that the expression of some drought-inducible genes, in addition to many GA inducible genes, was upregulated. More evidently, in 2h dehydrated spy-3 plants, the expression of many drought-responsive genes, especially LEA protein genes, is higher than that in wild-type plants. In addition, some DREB2A specific downstream gene expressions were enhanced in spy-3 mutant, in early dehydration stress.
