ABI5 acts downstream of ABI3 to execute an ABA‐dependent growth arrest during germination

• DOI: 10.1046/j.1365-313x.2002.01430.x
• Publication Date: 2003-03-12T22:07:57Z
• Authors: Luis Lopez‐Molina; Sébastien Mongrand; Derek T. McLachlin; Brian T. Chait; Nam‐Hai Chua
• Keywords: Cell Nucleus/genetics/metabolism; info:eu-repo/classification/ddc/580; Arabidopsis; Germination; Germination/drug effects/genetics; Transcription Factors/genetics/metabolism; 03 medical and health sciences; Plant Growth Regulators; Gene Expression Regulation, Plant; Plant Growth Regulators/pharmacology; Arabidopsis Proteins/genetics/metabolism; Cell Nucleus; 0303 health sciences; Arabidopsis Proteins; Abscisic Acid/pharmacology; Gene Expression Regulation, Plant/drug effects; Plants, Genetically Modified; Seeds/drug effects/genetics/growth & development; ddc:580; Basic-Leucine Zipper Transcription Factors; Seeds; Arabidopsis/drug effects/genetics/growth & development; Abscisic Acid; Transcription Factors

Summary The development of a germinating embryo into an autotrophic seedling is arrested under conditions water deficit. This ABA‐mediated developmental checkpoint requires the bZIP transcription factor ABI5. Here, we used abi3‐1 , which also unable to execute this checkpoint, investigate relative role ABI3 and ABI5 in process. In wild‐type Arabidopsis plants, expression activity parallel those described for following stratification. During process, transcript levels late embryogenesis genes such as AtEm1 AtEm6 are re‐induced, might be responsible acquired osmotic tolerance germinated embryos whose growth arrested. greatly reduced mutants, has low or expression. Cross complementation experiments showed that 35S‐ABI5 could complement whereas 35S‐ABI3 cannot abi5‐4 . These results indicate acts downstream reactivate programmes arrest embryos. Although consistently located nucleus, chromosomal immunoprecipitation (ChIP) revealed ABA increases occupancy on promoter.