ACAULIS5 Is Required for Cytokinin Accumulation and Function During Secondary Growth of Populus Trees

Copyright © 2020 Milhinhos, Bollhöner, Blazquez, Novák, Miguel and Tuominen..

In the primary root and young hypocotyl of Arabidopsis, ACAULIS5 promotes translation of SUPPRESSOR OF ACAULIS51 (SAC51) and thereby inhibits cytokinin biosynthesis and vascular cell division. In this study, the relationships between ACAULIS5, SAC51 and cytokinin biosynthesis were investigated during secondary growth of Populus stems. Overexpression of ACAULIS5 from the constitutive 35S promoter in hybrid aspen (Populus tremula × Populus tremuloides) trees suppressed the expression level of ACAULIS5, which resulted in low levels of the physiologically active cytokinin bases as well as their direct riboside precursors in the transgenic lines. Low ACAULIS5 expression and low cytokinin levels of the transgenic trees coincided with low cambial activity of the stem. ACAULIS5 therefore, contrary to its function in young seedlings in Arabidopsis, stimulates cytokinin accumulation and cambial activity during secondary growth of the stem. This function is not derived from maturing secondary xylem tissues as transgenic suppression of ACAULIS5 levels in these tissues did not influence secondary growth. Interestingly, evidence was obtained for increased activity of the anticlinal division of the cambial initials under conditions of low ACAULIS5 expression and low cytokinin accumulation. We propose that ACAULIS5 integrates auxin and cytokinin signaling to promote extensive secondary growth of tree stems.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:11

Enthalten in:

Frontiers in plant science - 11(2020) vom: 01., Seite 601858

Sprache:

Englisch

Beteiligte Personen:

Milhinhos, Ana [VerfasserIn]
Bollhöner, Benjamin [VerfasserIn]
Blazquez, Miguel A [VerfasserIn]
Novák, Ondřej [VerfasserIn]
Miguel, Célia M [VerfasserIn]
Tuominen, Hannele [VerfasserIn]

Links:

Volltext

Themen:

ACAULIS5
Cytokinin
Journal Article
POPACAULIS5
Polyamine
Populus tremula × Populus tremuloides
Thermospermine
Wood development
Xylem

Anmerkungen:

Date Revised 12.12.2020

published: Electronic-eCollection

Citation Status PubMed-not-MEDLINE

doi:

10.3389/fpls.2020.601858

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM318697270