Dynamics of DNA methylation and Histone H4 acetylation during floral bud differentiation in azalea.

Mónica Meijón,Luis Valledor,Roberto Rodríguez,María Jesús Cañal,Isabel Feito

doi:10.1186/1471-2229-10-10

Abstract

BackgroundThe ability to control the timing of flowering is a key strategy for planning production in ornamental species such as azalea, however it requires a thorough understanding of floral transition. Floral transition is achieved through a complex genetic network and regulated by multiple environmental and endogenous cues. Dynamic changes between chromatin states facilitating or inhibiting DNA transcription regulate the expression of floral induction pathways in response to environmental and developmental signals. DNA methylation and histone modifications are involved in controlling the functional state of chromatin and gene expression.ResultsThe results of this work indicate that epigenetic mechanisms such as DNA methylation and histone H4 acetylation have opposite and particular dynamics during the transition from vegetative to reproductive development in the apical shoots of azalea. Global levels of DNA methylation and histone H4 acetylation as well as immunodetection of 5-mdC and acetylated H4, in addition to a morphological study have permitted the delimitation of four basic phases in the development of the azalea bud and allowed the identification of a stage of epigenetic reprogramming which showed a sharp decrease of whole DNA methylation similar to that is defined in other developmental processes in plants and in mammals.ConclusionThe epigenetic control and reorganization of chromatin seem to be decisive for coordinating floral development in azalea. DNA methylation and H4 deacetylation act simultaneously and co-ordinately, restructuring the chromatin and regulating the gene expression during soot apical meristem development and floral differentiation.

Highlights

The ability to control the timing of flowering is a key strategy for planning production in ornamental species such as azalea, it requires a thorough understanding of floral transition
Histological study and DNA methylation Macromorphological and micromorphological observations carried out in buds collected during floral transition showed differential morphologies and structures (Fig. 1)
In December, both cultivars retained the same level of DNA methylation, 19%

Summary

Introduction

The ability to control the timing of flowering is a key strategy for planning production in ornamental species such as azalea, it requires a thorough understanding of floral transition. Transition from the vegetative to reproductive stage is the most dramatic change during plant development, involving the transmission of the integrated signal of floral induction to the floral meristem identity genes and floral morphogenesis The regulation of this process is essential for plant development, and it is achieved by a complex genetic network. The switch to flowering involves the integration and coordination of the perception of environment (day length, light conditions and temperature) with endogenous factors such as developmental status and age This coordination is decisive for reproductive success in plants and its correlation with epigenetic mechanisms such as DNA methylation and histone modification has been demonstrated in several species [4,6,7,8]

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Discussion

Conclusion