The Arabidopsis DELAY OF GERMINATION 1 gene affects ABSCISIC ACID INSENSITIVE 5 (ABI5) expression and genetically interacts with ABI3 during Arabidopsis seed development

Abstract

These authors contributed equally to this work. SUMMARYThe seed expressed gene DELAY OF GERMINATION (DOG) 1 is absolutely required for the induction of dormancy. Next to a non-dormant phenotype, the dog1-1 mutant is also characterized by a reduced seed longevity suggesting that DOG1 may affect additional seed processes as well. This aspect however, has been hardly studied and is poorly understood. To uncover additional roles of DOG1 in seeds we performed a detailed analysis of the dog1 mutant using both transcriptomics and metabolomics to investigate the molecular consequences of a dysfunctional DOG1 gene. Further, we used a genetic approach taking advantage of the weak aba insensitive (abi) 3-1 allele as a sensitized genetic background in a cross with dog1-1. DOG1 affects the expression of hundreds of genes including LATE EMBRYOGENESIS ABUNDANT and HEAT SHOCK PROTEIN genes which are affected by DOG1 partly via control of ABI5 expression. Furthermore, the content of a subset of primary metabolites, which normally accumulate during seed maturation, was found to be affected in the dog1-1 mutant. Surprisingly, the abi3-1 dog1-1 double mutant produced green seeds which are highly ABA insensitive, phenocopying severe abi3 mutants, indicating that dog1-1 acts as an enhancer of the weak abi3-1 allele and thus revealing a genetic interaction between both genes. Analysis of the dog1 and dog1 abi3 mutants revealed additional seed phenotypes and therefore we hypothesize that DOG1 function is not limited to dormancy but that it is required for multiple aspects of seed maturation, in part by interfering with ABA signalling components.

Signalling regulators of abscisic and gibberellic acid pathways are involved in dormancy breaking of Norway maple (Acer platanoides L.) seeds

“…Quantitative changes in ABI5 and 14-3-3 protein accumulation ABI5 plays a key role in ABA signal transduction, but its association with regulation of seed germination and seedling growth is not yet well elucidated (Dekkers et al 2016). ABI5 functions as a transcriptional regulator by binding to an ABA-responsive element, ABRE, which is found in the ABA-induced gene promoters (Hattori et al 2002).…”

“…ABI5 is involved in stress response and development adjustments (Fujita et al 2011). The role of ABI5 in dormancy induction is discussed (Finkelstein et al 2008) mostly because of the lack of such research concerning Arabidopsis seeds (Dekkers et al 2016). Research with orthologues, however, has confirmed that ABI5 homologues are more highly expressed in dormant sorghum cultivars (Rodríguez et al 2009).…”

The Role and Regulation of ABI5 (ABA-Insensitive 5) in Plant Development, Abiotic Stress Responses and Phytohormone Crosstalk

“…Possibly, DOG1 acts as a positive regulator of ABI5 and as a result, activates many LEA and HSP ( HEAT SHOCK PROTEIN ) genes. Additionally, DOG1 may function together with ABI3 in the regulation of seed maturation (Dekkers et al, 2016) ( Figure 2A ).…”

DELAY OF GERMINATION1 requires PP2C phosphatases of the ABA signalling pathway to control seed dormancy

“…However, both ABA and DOG1 have to be present to induce seed dormancy as absence of a single one of these two regulators results in complete lack of dormancy even when the other regulator is highly accumulated 16, 19, 24, 25 . DOG1 was also shown to be required for multiple aspects of seed maturation, partially by interfering with ABA signalling components 26 . This suggests that the two pathways converge at downstream steps.…”