Unraveling Superior Functions and Key Amino Acid Residues of Antarctic Moss Plastocyanin in Stress Tolerance in Plants
- 주제어 (키워드) 광합성 , 환경 스트레스 , 극지 이끼 , 전자 전달 , 플라스토시아닌
- 발행기관 서강대학교 일반대학원
- 지도교수 이병하
- 발행년도 2025
- 학위수여년월 2025. 8
- 학위명 박사
- 학과 및 전공 일반대학원 생명과학과
- 실제 URI http://www.dcollection.net/handler/sogang/000000081823
- UCI I804:11029-000000081823
- 본문언어 한국어
- 저작권 서강대학교 논문은 저작권 보호를 받습니다.
초록 (요약문)
광합성은 빛 에너지를 화학 에너지로 전환하여 지구상의 거의 모든 생명을 유지시키는 근본적인 생물학적 과정이다. 광합성은 가뭄, 염분 및 극한 온도와 같은 환경적 스트레스에 의해 방해를 받으며, 이로 인해 식물에서 이산화탄소 흡수가 저하되고, 광합성 기구가 손상되며 세포 구조가 불안정해진다. 식물은 스트레스의 영향을 완화하고 에너지 균형을 유지하기 위해 항산화 활성화, 전자 전달 및 유전자 발현의 조절 등 다양한 적응 메커니즘을 활용하지만 그 과정에서 식물의 성장과 생산성 감소를 가져온다. 본 연구는 광합성을 통해 환경 스트레스에 의한 회복력을 높이는 식물의 적응 메커니즘과 에너지 신호 전달 경로의 역할을 설명하고 있다. 염분 스트레스와 같은 비생물적 스트레스는 광합성과 같은 필수적인 과정을 방해하여 식물의 성장과 작물 생산성을 크게 저해한다. 이전 연구에서, PaPC가 식물 성장과 염분 스트레스 내성을 크게 향상시킨다는 사실을 발견했다. PaPC의 기능을 더 깊이 이해하기 위해, PaPC를 Arabidopsis의 플라스토시아닌 유전자(AtPC1과 AtPC2)와 비교 분석했다. 그 결과, PaPC를 과발현한 식물은 광합성 효율, 생체량, 그리고 스트레스 내성에 대해 AtPC1 또는 AtPC2를 과발현한 식물 및 야생형에 비해 뛰어나게 향상된 표현형을 보였다. 또한, PaPC를 과발현한 벼는 정상 조건과 염분 스트레스 조건 모두에서 수확 잠재력과 광합성 성능에서 향상된 모습을 보였다. PaPC의 이러한 효과를 담당하는 주요 아미노산 잔기를 확인하였으며, 이를 AtPC2에 치환한 결과 Arabidopsis, 담배, 토마토를 포함한 여러 식물 종에서 광합성과 스트레스 내성이 유사하게 향상되었다. 본 연구는 극한 환경에서 생존하는 생물이 가치 있는 유전적 자원임을 강조하며, 성장 저하 없이 생산성을 크게 향상시킬 수 있는 새로운 광합성 기반 전략을 제시한다.
more초록 (요약문)
Photosynthesis is a fundamental biological process that sustains nearly all life on Earth by converting light energy into chemical energy. Photosynthesis is disrupted by environmental stresses such as drought, salinity and extreme temperatures, as photosynthesis impairs CO2 uptake, damages photosynthetic machinery and destabilizes cellular structures. Plants employed adaptive mechanisms, including antioxidant activation and dynamic regulation of electron transport and gene expression, to mitigate stress impacts and maintain energy balance, albeit at the cost of reduced growth and productivity. This study explained adaptive mechanisms that conferred resilience through photosynthesis and the central roles of energy signaling pathways in plants. Abiotic stress, such as salinity, posed significant challenges to plant growth and crop productivity by adversely affecting essential processes like photosynthesis. In a previous study, I found that plastocyanin gene (PaPC) from the Antarctic moss Polytrichastrum alpinum significantly improved plant growth and salt stress tolerance. To further elucidate the function of PaPC, I conducted a comparative analysis of PaPC with the Arabidopsis plastocyanin genes (AtPC1 and AtPC2). PaPC-overexpressing plants showed superior photosynthetic efficiency, increased biomass and increased stress tolerance compared to AtPC1- or AtPC2- overexpressing plants that were similar to the wild type in growth and stress tolerance. In addition, PaPC-overexpressing rice plants exhibited remarkable improvements in yield potential and photosynthetic performance normal and salt stress conditions. Key amino acid residues in PaPC responsible for these enhancements were identified, and their substitution into AtPC2 conferred similar improvements in photosynthesis and stress tolerance, including Arabidopsis, tobacco, and tomato. These findings highlight the potential of extremophiles as valuable genetic resources and present a novel photosynthesis-driven strategy for developing stress-resilient crops with significantly improved yield potential and no growth penalties.
more목차
Chapter 1. General introduction 1
1. Mechanisms of photosynthesis 2
1.1. Introduction of Photosynthesis: A Vital Process for Life on Earth 2
1.2. Mechanisms of Photosynthesis: Light-Dependent and Light-Independent Reactions 2
1.3. Photosynthetic Protein Complexes: Facilitators of Energy and Electron Transport 3
1.4. Thylakoid Membrane Architecture: Optimizing Photosynthetic Efficiency 4
1.5. Regulation of Photosynthesis: Balancing Energy Capture and Utilization 4
1.6. Cyclic Electron Transport: Supporting Energy Balance and Photoprotection 5
1.7. Plastocyanin: A Key Player in Photosynthetic Electron Transport. 6
1.8. Reactive Oxygen Species: Roles in Stress Response 7
2. Abiotic Stress and Photosynthesis: Trade-offs and Adaptive Mechanisms 9
2.1. Adaptations to Abiotic Stress: Mechanisms of Resilience in Plants 9
2.2. Abiotic Stress and Photosynthesis 10
2.3. Resource Allocation Under Stress: Balancing Growth and Survival 10
2.4. Energy Signaling: The Role of TOR and SnRK1 in Stress Adaptation 12
2.5. Improving Photosynthetic Efficiency Under Stress 14
2.6. Enhancing Stress Tolerance Through Genetic Engineering 16
Chapter 2. Enhanced Salt Stress Tolerance in Plants Without Growth Penalty Through Increased Photosynthesis Activity by Plastocyanin from Antarctic Moss 18
1. Introduction 19
2. Materials and methods 23
2.1. Planting Materials and Growth Conditions 23
2.2. Cloning of Antarctic Moss Gene and Generation of Transgenic Arabidopsis Plants 23
2.3. Measurement of cell size 25
2.4. Photosynthesis Product Measurements 26
2.5. Arabidopsis Stress Treatment and Analysis 27
2.6. Photosynthetic Efficiency Analysis 29
2.7. Protein Preparation, Immunoblot Analyses and TOR Activity Determination 29
2.8. Analysis of Non-Photochemical Quenching 30
2.9. Histochemical Detection of H2O2 and O2- in Plants 31
2.10. Transient Gene Expression in Leaf and Photosynthesis Analysis 31
2.11. Generation and Phenotypic Analysis of PaPC Overexpressing Rice 32
2.12. Protein 3 Dimension Modeling 34
3. Results 35
3.1. PaPC Overexpression Enhances Plant Growth 35
3.2. PaPC Overexpression Increases Photosynthetic Efficiency. 40
3.3. PaPC Overexpression Increases Salt Stress Tolerance 43
3.4. PaPC Overexpressing Plants Maintain Enhanced Photosynthetic Efficiency Under Salt Stress 48
3.5. Salt Tolerance in PaPC-OE is Dependent on PC-Mediated PET Activity 51
3.6. PaPC Overexpression Dissipates Excess Light Energy and Reduced the Accumulation of ROS Under Salt Stress 55
3.7. PaPC Overexpression Enhances Stability of Photosynthesis Protein Under Salt Stress 59
3.8. Photosynthesis Inhibition Differentially Affects TOR Activity in WT and PaPC-OE 61
3.9. Amino-Acid Substitutions in AtPC2 Increase Salt Stress Tolerance in Arabidopsis 63
3.10. Amino Acid-Substituted PC Increases Salt Stress Tolerance in Tobacco and Tomato 70
3.11. Transit Peptide Substitutions in AtPC2 Increase Salt Stress Tolerance 75
3.12. PaPC Overexpression Increases Tiller Production and Grain Yield in Rice 79
3.13. Amino Acid-Substituted PC Enhances Photosynthetic Efficiency in Barley 85
3.14. Cold Tolerance in PaPC-OE is Dependent on PC-Mediated PET Activity 88
3.15. PC Overexpression is not Associated with Heat Tolerance 93
4. Discussion 97
5. References 106
