DGIST Scholar: Mechanistic and functional characterization of an ultradian rhythm (UR) in Arabidopsis leaves

Department of New Biology Theses Ph.D.

Cited time in webofscience

Cited time in scopus

Mechanistic and functional characterization of an ultradian rhythm (UR) in Arabidopsis leaves

Title: Mechanistic and functional characterization of an ultradian rhythm (UR) in Arabidopsis leaves

Author(s): Vu Thi Quy

DGIST Authors: Vu Thi Quy ; Hong Gil Nam ; Sunghyun Hong

Advisor: 남홍길

Co-Advisor(s): Sunghyun Hong

Issued Date: 2021

Awarded Date: 2021/02

Type: Thesis

Subject: UR, excised Arabidopsis leaves, DNRR, EAR1, negative feedback loop, 초주일 리듬, 단절된 애기장대 잎, 새로운 뿌리발생, 역피드백 작용

Table Of Contents: Chapter I. General Introduction 1
1.1 Overview of biological rhythms and ultradian rhythms’ research 1
1.2 Objectives 3
Chapter II. Discovery and characteristics of an UR in excised Arabidopsis leaves 5
2.1 Introduction 5
2.2 Materials and Methods 6
2.3 Results 7
2.3.1 An ~3 h UR is discovered in promoter activity of some circadian clock-controlled genes in excised Arabidopsis leaves 7
2.3.2 The UR generation is driven by an oscillatory mechanism distinctive from circadian clock system 10
2.3.3 The UR is triggered in excised Arabidopsis leaves specifically 13
2.4 Discussion and conclusion 14
Chapter III. Strong positive correlation between the UR and de novo root regeneration (DNRR) process in excised Arabidopsis leaves 16
3.1 Introduction 16
3.2 Materials and methods 18
3.3 Results 20
3.3.1 Consistent patterns of the UR and DNRR in response to many internal and external factors 20
3.3.2 Widespread existence of ultradian oscillating genes with enrichment of hormonal pathways 26
3.4 Discussion and conclusion 33
Chapter IV. Mechanism of ROU1/EAR1 in the UR and DNRR regulation 35
4.1 Introduction 35
4.2 Materials and methods 35
4.3 Results 37
4.3.1 Mutants impaired in the UR generation delay rooting initiation and reduce rooting rate 37
4.3.2 EAR1, an ABA signalling component is a crucial UR regulator 38
4.3.3 ROU1/EAR1 positively regulates the UR generation and DNRR in an ABA-specific pathway which is decoupled from ABA-mediated inhibition of seed germination and root growth 42
4.3.4 Spatial localization of ROU1/EAR1 at the petiole and mechanism driving the UR in excised leaves 46
4.4 Discussion and conclusion 50
References 51
Summary in Korean 58
Acknowledgement 60
Curriculum Vitae 61