NDP kinase 2 regulates expression of antioxidant genes in Arabidopsis.

Abstract

NDP kinases (NDPKs) are multifunctional proteins involved in cell proliferation, development, and differentiation in eukaryotes. Previously, we reported that Arabidopsis NDP kinase 2 (AtNDPK2) is a component of H2O2-activated MAPK signaling in plants and demonstrated that its over-expression in plants alters cellular redox conditions (Proc. Natl. Acad. Sci. U. S. A., 100, 358-363, 2003). To elucidate how AtNDPK2 can regulate cellular redox state, we analyzed gene expression profiles of transgenic plants over-expressing AtNDPK2 using cDNA microarray technology. Constitutive over-expression of AtNDPK2 in plants induced numerous genes including those involved in cellular signal transduction and protection, suggesting that NDPKs are also multifunctional in plants. Among the induced genes, we further analyzed the expression of antioxidant genes by Northern blot analysis. Expression of peroxidase, catalase, thioredoxin, thioredoxin reductase, and peroxiredoxin was significantly increased in transgenic plants over-expressing AtNDPK2. Furthermore, the gene expression pattern obtained by Northern blotting was quantitatively consistent with the cDNA microarray analysis. Based on these observations, we suggest that down-regulation of cellular redox state in AtNDPK2 transgenic plants is mediated by genes involved in antioxidant and protective processes.(Communicated by Yasuyuki YAMADA, M. J. A., March 12, 2003)