陈坤明等《BMC Plant Biology 》2020年

论文题目：The NAD kinase OsNADK1 affects the intracellular redox balance and enhances the tolerance of rice to drought

论文作者：Xiang Wang#,Bin-Bin Li#,Tian-Tian Ma,Liang-Yu Sun,Li Tai,Chun-Hong Hu,Wen-Ting Liu,Wen-Qiang Li&Kun-Ming Chen*

论文摘要：

Background：NAD kinases (NADKs) are the only known enzymes that directly phosphorylate NAD(H) to generate NADP(H) in different subcellular compartments. They participate in multiple life activities, such as modulating the NADP/NAD ratio, maintaining the intracellular redox balance and responding to environmental stresses. However, the functions of individual NADK in plants are still under investigation. Here, a rice NADK, namely, OsNADK1, was identified, and its functions in plant growth regulation and stress tolerance were analysed by employing a series of transgenic plant lines.

Results：OsNADK1 is a cytosol-localized NADK in rice. It was expressed in all rice tissues examined, and its transcriptional expression could be stimulated by a number of environmental stress treatments. Compared with wild-type (WT) rice, the mutant plantosnadk1in whichOsNADK1was knocked out was a dwarf at the heading stage and had decreased NADP(H)/NAD(H), ascorbic acid (ASA)/dehydroascorbate (DHA) and reduced glutathione (GSH)/oxidized glutathione (GSSG) ratios, which led to increased oxidation states in the rice cells and sensitivity to drought. Moreover, certain stress-related genes showed differential expression patterns inosnadk1under both normal growth and drought-stress conditions compared with WT. Among these genes,OsDREB1Band several WRKY family transcription factors, e.g.,OsWRKY21andOsWRKY42, showed correlated co-expression patterns withOsNADK1inosnadk1and the plants overexpressing or underexpressingOsNADK1, implying roles for these transcription factors in OsNADK1-mediated processes. In addition, overexpression ofOsNADK1enhanced the drought tolerance of rice plants, whereas loss of function of the gene reduced the tolerance. Furthermore, the proline content was dramatically increased in the leaves of theOsNADK1-overexpressing lines under drought conditions.

Conclusions：Altogether, the results suggest that an OsNADK1-mediated intracellular redox balance is involved in the tolerance of rice plants to drought.

论文链接：https://bmcplantbiol.biomedcentral.com/articles/10.1186/s12870-019-2234-8