HSP90 canonical content organizes a molecular scaffold mechanism to progress flowering.
Highly interactive signaling processes constitute a set of parameters intertwining in a continuum mode to shape body formation and development. A sophisticated gene network is required to integrate environmental and endogenous cues in order to modulate flowering. However, the molecular mechanisms that coordinate the circuitries of flowering genes remain unclear. Here using complemented experimental approaches, we uncover the decisive and essential role of HEAT SHOCK PROTEIN 90 (HSP90) in restraining developmental noise to an acceptable limit. Localized depletion of HSP90 mRNAs in the shoot apex resulted in low penetrance of vegetative-to-reproductive phase transition and completely abolished flower formation. Extreme variation in expression of flowering genes was also observed in HSP90 mRNA-depleted transformed plants. Transient heat-shock treatments moderately increased HSP90 mRNA levels and rescued flower arrest. The offspring had a low, nevertheless noticeable failure to promote transition from vegetative into the reproductive phase and showed flower morphological heterogeneity. In floral tissues a moderate variation in HSP90 transcript levels and in the expression of flowering genes was detected. Key flowering proteins comprised clientele of the molecular chaperone demonstrating that the HSP90 is essential during vegetative-to-reproductive phase transition and flower development. Our results uncover that HSP90 consolidates a molecular scaffold able to arrange and organize flowering gene network and protein circuitry, and effectively counterbalance the extent to which developmental noise perturbs phenotypic traits.
Molecular Biology Laboratory, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
Theoni
T
Margaritopoulou
Molecular Biology Laboratory, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
Nikoleta
N
Kryovrysanaki
Molecular Biology Laboratory, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
Panagiota
P
Megkoula
Molecular Biology Laboratory, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
Constantinos
C
Prassinos
Molecular Biology Laboratory, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
Despoina
D
Samakovli
Molecular Biology Laboratory, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
Dimitra
D
Milioni
Molecular Biology Laboratory, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
Polydefkis
P
Hatzopoulos
D017360:Arabidopsis / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins / Q000502:physiology; D035264:Flowers / Q000254:growth & development*; D018841:HSP90 Heat-Shock Proteins / Q000502:physiology*; D018520:Plant Shoots / Q000254:growth & development; D030821:Plants, Genetically Modified / Q000254:growth & development / Q000502:physiology; D034622:RNA Interference / Q000502:physiology
D029681:Arabidopsis Proteins; D018841:HSP90 Heat-Shock Proteins
Arabidopsis; flower development; heat shock protein 90; protein interaction; transcriptional regulation