Abstract
Recently we demonstrated that chloroplastic NADPH pyrophosphohydrolase, AtNUDX19, is involved in the regulation of photosynthesis and antioxidative system during photoacclimation through hydrolysis of NADPH, suggesting that the levels and/or redox states of NADP(H) is crucial for regulating stress responses. Here we revealed the regulatory mechanisms of such stress responses by a microarray analysis in a knockout mutants lacking AtNUDX19 (KO-nudx19) grown under normal and high-light conditions.
The expression levels of >600 genes were altered in the KO-nudx19 plants compared with the wild-type plants under normal and high-light. A large number of genes encoded factors related to hormonal responses (jasmonic acid: JA, abscisic acid: ABA, and salicylic acid: SA). The KO-nudx19 plants were insensitive to treatment with JA and ABA, and hyper-sensitive to wounding and osmotic stress. Furthermore, the KO-nudx19 plants showed hyper-sensitive to treatment with SA. These findings indicated that the regulation of levels and/or redox states of NADP(H) by AtNUDX19 is essential for modulating plant stress responses through hormonal regulation.
