DGIST Scholar: Molecular mechanisMaster for maintenance of primary root apical meristem along aging in Arabidopsis

Department of New Biology Theses Ph.D.

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Molecular mechanisMaster for maintenance of primary root apical meristem along aging in Arabidopsis

Title: Molecular mechanisMaster for maintenance of primary root apical meristem along aging in Arabidopsis

Author(s): Timilsina Rupak

DGIST Authors: Woo, Hye Ryun ; Rupak, Timilsina ; Nam, Hong Gil

Advisor: 우혜련

Co-Advisor(s): Hong Gil Nam

Issued Date: 2019

Awarded Date: 2019-08

Type: Thesis

Description: Root apical meristem, Quiescent Center, Cell division and differentiation, Auxin, ORESARA 15

Table Of Contents: Abstract i
Table of contents iii
List of Figures and Tables v
Abbreviations viii
Chapter I General Introduction - 1 -
1.1 Overview of plant senescence - 1 -
1.2 Regulation of senescence - 2 -
1.3 Senescence of organs - 3 -
1.3.1 Root senescence - 4 -
1.4 Objectives - 10 -
Chapter II. Characterization of changes in molecular, cellular, and physiological characteristics in primary RAM along age - 11 -
2.1 Introduction - 11 -
2.2 Materials and Methods - 15 -
2.3 Results - 19 -
2.3.1 The rates of cell division and auxin and cytokinin responses in the primary RAM change as the root ages - 19 -
2.3.2 Size of QC cells and expression of QC cell-specific marker genes in the primary RAM are temporally changed - 21 -
2.3.3 Genotoxic stress tolerance of QC cells decreases with root age - 25 -
2.3.4 QC cells protect theMasterelves from genotoxic stress via mechanisMaster other than asymmetric chromosomal segregation (ACS) - 27 -
2.3.5 The rate of QC cell division is temporally regulated - 32 -
2.4 Discussion and conclusion - 37 -
Chapter III. ORESARA 15 (ORE15) is a temporal regulator of maintenance of primary RAM along age - 41 -
3.1 Introduction - 41 -
3.2 Materials and methods - 44 -
3.3 Results - 52 -
3.3.1 ORE15 shows temporal decrease in expression level in primary RAM - 52 -
3.3.2 ORE15 regulates the size of RAM - 54 -
3.3.3 ORE15 regulates the dynamics of meristem size along age - 56 -
3.3.4 ORE15 regulates the dynamics of root growth rate along age - 58 -
3.3.5 ORE15 controls the cell size in RAM and other zones in root - 62 -
3.3.6 ORE15 regulate cell division in proximal RAM and stem-cell niche - 64 -
3.3.7 ORE15 is a temporal regulator of cell division dynamics in RAM - 71 -
3.3.8 ORE15 is invloved in the auxin hormonal regulation of RAM - 76 -
3.3.9 ORE15 modulates the process of auxin transportation in RAM - 81 -
3.3.10 ORE15 and auxin positively feedback each other - 85 -
3.3.11 Downstream targets of ORE15 - 87 -
3.4 Discussion - 94 -
Summary in Korean - 109 -
Acknowledgement - 112 -
Curriculum Vitae - 113 -