Abstract Detail

Genetics Section

Fernando, Dilukshi [1], Belmonte, Mark F. [2], Schroeder, Dana [1].

Role of DE-ETIOLATED 1 (DET1) in regulation of seed germination in ABA mediated salinity and osmotic stress conditions in Arabidopsis .

Seed germination is regulated positively by light and negatively by the dormancy-promoting phytohormone abscisic acid (ABA). DE-ETIOLATED 1 (DET1), a negative regulator of light development, exhibits altered responses to ABA, salt and osmotic stress. Due to crosstalk between light and hormone signalling we investigated the role of DET1 in ABA mediated stress conditions. det1 mutants are sensitive to ABA inhibition of seed germination. In contrast, det1 exhibits early germination in control conditions as well as salt and mannitol resistant germination. LONG HYPOCOTYL 5 (HY5), a positive regulator of light signalling, also positively regulates ABA signalling by promoting transcription of ABSCISIC ACID INSENSITIVE 5 (ABI5) during seed germination. HY5 has been implicated in salt stress thus we examined the role of HY5 and ABI5 in det1 salt and mannitol resistant germination. While hy5 mutation completely suppressed the det1 phenotype, abi5 had no significant effect. Thus, det1 salt/mannitol resistant germination requires HY5 but not ABI5. In order to identify other genes mis-regulated in det1 which might be causing precocious germination, publicly available microarray data from CATdb (a Complete Arabidopsis Transcriptome data base) was used for enrichment analysis and different GO terms were identified using ChipEnrich. The analysis revealed ABA RESPONSIVE ELEMENT BINDING FACTOR 3 (ABF3) is downregulated in det1 dark grown seedlings. We propose ABF3 is downregulated in det1 seeds and could be the factor that drives the precocious germination in salt/mannitol and control conditions. Here we investigate the basis of salt and mannitol phenotypes of det1 mutants and the genetic interactions between the ABF genes and DET1.

1 - University of Manitoba, Biological Sciences, 520 Buller Building, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
2 - University of Manitoba, Biological Sciences, Winnipeg, MB, R3T 2N2, Canada

Keywords:
Seed germination
ABA
osmotic stress
salt stress.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PGN006
Abstract ID:262
Candidate for Awards:Genetics Section Poster Award,Ian and Syvia Taylor Award,CSPB President's Award for Best Student Presentation