The embryonic leaf identity gene FUSCA3 also regulates vegetative phase transitions by negatively regulating ethylene action in Arabidopsis
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ABSTRACT: The embryonic temporal regulator FUSCA3 (FUS3) plays major roles in the establishment of embryonic leaf identity and regulation of developmental timing. Loss-of-function mutations of this B3-domain transcription factor result in replacement of cotyledons with leaves and precocious germination, while constitutive misexpression causes the conversion of leaves into cotyledon-like organs and delays vegetative and reproductive phase transitions. To identify downstream targets of FUS3 involved in vegetative phase transitions, we performed microarray analysis on seedlings that transiently activate FUS3 using the AtML1:FUS3-GR-DEX inducible system. Using this construct, FUS3 is ectopically expressed in the ML1 or epidermal layer and becomes activated upon addition of dexamethasone. We found that activation of FUS3 after germination dampens the expression of genes involved in the biosynthesis and response to the plant hormone ethylene, while a loss-of-function fus3 mutant shows many phenotypes consistent with increased ethylene signaling. This FUS3-dependent regulation of ethylene signaling also impinges on timing functions outside of embryogenesis. Loss of FUS3 function results in accelerated vegetative phase change and this is again partially dependent on functional ethylene action. This alteration in vegetative phase transition is dependent on both embryonic and vegetative FUS3 function, suggesting that this important transcriptional regulator controls both embryonic and vegetative developmental timing. This study indicates that the embryonic regulator FUS3 not only regulates the embryonic-to-vegetative phase transition through hormonal regulation, but also functions postembryonically to modulate vegetative phase transitions by negatively regulating ethylene action.
ORGANISM(S): Arabidopsis thaliana
SUBMITTER: Shelley Lumba
PROVIDER: E-MEXP-3465 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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