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DREB2 Family Transcription Factors Promote the Expression of Phytocystatin1 in Arabidopsis thaliana During Seed Germination
Ist Teil von
Journal of Plant Biology(한국식물학회지), 2021, 64(1), , pp.45-53
Ort / Verlag
Singapore: Springer Singapore
Erscheinungsjahr
2021
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Phytocystatins (PhyCYSs) are plant-specific proteinaceous inhibitors of cysteine proteases (CPs) that regulate protein turnover and defense responses. Here, we characterized a member of the
PhyCYS
gene family in
Arabidopsis thaliana
,
AtCYS1
, during seed germination.
AtCYS1
transcript level and
AtCYS1
promoter-driven β-glucuronidase (GUS) activity gradually increased during germination, as measured by quantitative reverse transcription PCR (qRT-PCR) and GUS staining assays, respectively. The level and activity of the AtCYS1 protein were up-regulated during germination, as shown by western blot and CP inhibitory activity analyses, respectively. In addition, a canonical dehydration-responsive element (DRE) was identified in the
AtCYS1
promoter. Electrophoretic mobility shift assays (EMSAs) revealed that the DRE-binding factor 2C (DREB2C) binds directly to the
AtCYS1
promoter. Transient transactivation assays using
Arabidopsis
leaf protoplasts showed that DREB2A and DREB2C act as transcriptional activators of
AtCYS1
. In
DREB2C
overexpression lines, AtCYS1 protein levels were elevated, while the endogenous CP activity was reduced. However,
AtCYS1
overexpression lines (
35S:AtCYS1
) and the
cys1-1
null mutant, characterized by a quantitative imbalance in the AtCYS1 protein level, showed delayed germination under normal growth conditions. These results suggest that DREB2 proteins act as transcriptional activators of the
AtCYS1
gene, and an imbalance in the level of AtCYS1 inhibits seed germination.