ice ubiquitin ligase EL5 prevents rootmeristematic cell death under high nitrogenconditions and interacts with a cytosolic GAPDH

摘要

Root formation in rice transformants overexpressing mutatedEL5(mEL5) was severely inhibited because ofmeristematic cell death. Cell death was caused by nitrogen sources, particularly nitrate forms, in the culture medium.Nitrite treatment increased thecytokinin contents in roots, but mEL5 contained more cytokinins than non-transformants. Transcriptome profiling showed overlaps between nitrite-responsive genes in non-transformants andgenes with altered expression in untreated mEL5. These results indicate that impairment of EL5 function activatesnitrogen signaling despite the absence of a nitrogen source. Physical interaction between the EL5 C-terminal regionand a cytosolic glyceraldehyde-3-phosphate dehydrogenase, OsGapC2, was demonstratedin vitroandin vivo.Elucidation of the role of glyceraldehyde-3-phosphate dehydrogenase in oxidative cell death in plants is expected infuture.