Regulation of xylem fibers differentiation by gibberellins through DELLA-KNAT1 interaction.
Fiche publication
Date publication
novembre 2018
Journal
Development (Cambridge, England)
Auteurs
Membres identifiés du Cancéropôle Est :
Dr BAUMBERGER Nicolas
Tous les auteurs :
Felipo-Benavent A, Úrbez C, Blanco-Touriñán N, Serrano-Mislata A, Baumberger N, Achard P, Agustí J, Blázquez MA, Alabadí D
Lien Pubmed
Résumé
The thickening of plant organs is supported by secondary growth, a process by which new vascular tissues (xylem and phloem) are produced. Xylem is composed of several cell types, including xylary fibers, parenchyma and vessel elements. In Arabidopsis, it has been shown that fibers are promoted by the class-I KNOX gene and the plant hormones gibberellins, and repressed by a small set of receptor-like kinases, but we lack a mechanistic framework to integrate their relative contributions. Here we show that DELLAs, negative elements of the gibberellin signaling pathway, physically interact with KNAT1 and impair its binding to KNAT1 binding sites. Our analysis also indicates that at least 37% of the transcriptome mobilized by KNAT1 is potentially dependent on this interaction, and includes genes involved in secondary cell wall modifications and phenylpropanoid biosynthesis. Moreover, the promotion by constitutive overexpression of of fiber formation and the expression of genes required for fiber differentiation were still reverted by DELLA accumulation, in agreement with post-translational regulation of KNAT1 by DELLA proteins. These results suggest that gibberellins enhance fiber development by promoting KNAT1 activity.
Mots clés
Hormones, Lignin, Plant vasculature, Secondary cell wall
Référence
Development. 2018 Nov 2;: