EARLY BUD-BREAK 1 and EARLY BUD-BREAK 3 control resumption of poplar growth after winter dormancy

Abdul Azeez,Victor B Busov,Rajesh Kumar Singh,Madhumita Dash,Steve H Strauss,Yiru Chen Zhao,Yordan S Yordanov,Katja Stojkovič,Rishikesh P Bhalerao,Pal Miskolczi

doi:10.1038/s41467-021-21449-0

Abstract

Bud-break is an economically and environmentally important process in trees and shrubs from boreal and temperate latitudes, but its molecular mechanisms are poorly understood. Here, we show that two previously reported transcription factors, EARLY BUD BREAK 1 (EBB1) and SHORT VEGETATIVE PHASE-Like (SVL) directly interact to control bud-break. EBB1 is a positive regulator of bud-break, whereas SVL is a negative regulator of bud-break. EBB1 directly and negatively regulates SVL expression. We further report the identification and characterization of the EBB3 gene. EBB3 is a temperature-responsive, epigenetically-regulated, positive regulator of bud-break that provides a direct link to activation of the cell cycle during bud-break. EBB3 is an AP2/ERF transcription factor that positively and directly regulates CYCLIND3.1 gene. Our results reveal the architecture of a putative regulatory module that links temperature-mediated control of bud-break with activation of cell cycle.

Highlights

Bud-break is an economically and environmentally important process in trees and shrubs from boreal and temperate latitudes, but its molecular mechanisms are poorly understood
Since the expression profiles of these two genes indicated that they may regulate each other, we studied the expression of SHORT VEGETATIVE PHASE-Like (SVL) in EARLY BUD BREAK 1 (EBB1) over- (EBB1-OE) and under-expressing (EBB1-ami) plants
To determine whether Early Bud-break 3 (EBB3) acts up- or downstream of SVL, we studied SVL expression in EBB3 overexpressing (EBB3-OE) and

Summary

Introduction

Bud-break is an economically and environmentally important process in trees and shrubs from boreal and temperate latitudes, but its molecular mechanisms are poorly understood. EBB3 is a temperature-responsive, epigeneticallyregulated, positive regulator of bud-break that provides a direct link to activation of the cell cycle during bud-break. Resumption of active growth requires prolonged exposure of the bud to low temperatures[5,20,21,22]. This phase, known as dormancy release, ensures that plants resume growth only after the stable return of favorable growth conditions; in essence, it represents a clock measuring the length of winter[23]

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Results

Conclusion