NADP-Isocitrate Dehydrogenase Mediates Response Of Arabidopsis Stem Cells To Nutritional Stress

Stem cells provide the basis of plant postembryonic development and determine the differentiation and development of roots,stems,leaves and other organs.In Arabidopsis thaliana,WUSCHEL(WUS)and WUSCHEL homologous family proteins(WOX)regulate stem cell maintenance in shoot apical meristem,root apical meristem and vascular cambium,respectively.At the same time,the growth and development of plants are also affected by the external environmental conditions.However,it is not clear how external nutritional conditions affect the maintenance and differentiation of plant stem cells.Isocitrate dehydrogenase is a key metabolic enzyme in the tricarboxylic acid cycle(TCA).In this study,cytoplasmic isocitrate dehydrogenase(ICDH)has been shown to regulate the response of plant stem cells to nutritional starvation.In this study,various experimental methods were used to demonstrate that ICDH can interact with WUS,WOX5 and WOX4 proteins as a complex,respectively,which can directly bind to the promoter of WUS,WOX5 and WOX4 genes and regulate their expression.It was further found that ICDH could enter the nucleus in response to nutritional stress.Nutrient stress can significantly promote root elongation of wild Arabidopsis thaliana,but inhibit leaf differentiation.The icdh-2 knockout mutant showed hypersensitivity to nutritional stress,while the transgenic plants with overexpressed ICDH protein showed higher resistance to nutritional stress.Nutritional stress inhibited the expression of WUS in wild Arabidopsis thaliana,but promoted the expression of WOX5.In icdh-2 mutants,nutritional stress inhibited WUS expression more significantly,but did not promote WOX5 expression.The results of this study preliminarily demonstrated the important role of ICDH in maintaining and differentiating Arabidopsis stem cells under nutritional stress.