초록 ▼

Ⅲ. 연구개발의 내용 및 범위
- BRs transcription factor에 의한 식물 호르몬 생합성 유전자의 발현 변화에 관한 연구
- EMSA를 통한 BRs transcription factor와 식물 호르몬 생합성 유전자의 promoter 간의 in vitro 결합에 관한 연구
- ChIP를 통한 BRs transcription factor와 식물 호르몬 생합성 유전자 promoter 간의 in vivo 결합에 관한 연구
- ChIP-on-chip을 통한 BRs 신호에 의해 직접적으로 조절받는 식물 호

Ⅲ. 연구개발의 내용 및 범위
- BRs transcription factor에 의한 식물 호르몬 생합성 유전자의 발현 변화에 관한 연구
- EMSA를 통한 BRs transcription factor와 식물 호르몬 생합성 유전자의 promoter 간의 in vitro 결합에 관한 연구
- ChIP를 통한 BRs transcription factor와 식물 호르몬 생합성 유전자 promoter 간의 in vivo 결합에 관한 연구
- ChIP-on-chip을 통한 BRs 신호에 의해 직접적으로 조절받는 식물 호르몬 생합성 유전자의 목록 작성
- Promoter-GUS system을 이용한 유전자의 시·공간적 발현 패턴 조사
- 선별된 식물 호르몬 생합성 유전자의 돌연변이체의 유전학적 및 표현형적 연구
- 식물 호르몬 내생 함량 분석에 관한 연구
- 데이터 종합 분석

Abstract ▼

Interactions of plant hormones are essential for exerting their physiological actions in growth and development of plants. Among various hormonal interactions, networks for maintaining endogenous levels of hormones are the most up-stream interactions, suggesting that they are primary factors for hom

Interactions of plant hormones are essential for exerting their physiological actions in growth and development of plants. Among various hormonal interactions, networks for maintaining endogenous levels of hormones are the most up-stream interactions, suggesting that they are primary factors for homeostasis of plant hormones in plants. To establish regulatory networks for maintaining endogenous level of plant hormones, molecular regulations for biosynthesis of Abscisic acid (ABA) and ethylene by brassinosteroids (BRs) were investigated in Arabidopsis thaliana.
When brassinolide (BL) was exogenously applied, expression of an ABA biosynthetic gene, ABA2, was decreased at early phase of application. BR deficient mutants, det2 and cyp85a1a2, showed increased expression level of ABA2. BR dominant mutants of BR transcription factors, bes1-D and bzr1-1D, showed decreased expression level of ABA2. Next, tissue specific expression of ABA2 was examined using GUS reporter gene system. The change of ABA2 expression was detected by application of BL and BRZ, confirming that ABA2 transcript level is down-regulated by BR signalling. pABA2-GUS was observed in vascular tissues, suggesting that ABA biosynthesis by ABA2 occurs in the tissues.
Electrophoretic mobility shift assay (EMSA) showed that BES1 and BZR1 control ABA2 expression by direct binding to E-box sequences in putative promoter region of ABA2. Endogenous levels of ABA were increased in det2 and cyp85a1a2, and decreased in bes1-D and bzr1-1D, demonstrating that BR signalling down-regulates endogenous level of ABA in A. thaliana. bes1-D and bes1 KO showed different ABA sensitivity, which could lead change of germination rates of seeds. One of the reasons for change of germination rate is likely to be alternation of gene expressions of GA3ox1 and α-amylase in the seeds.
Ethylene biosynthetic gene, ACO4, was strongly expressed in shoot rather than root. ACO4 transcript level was decreased at early phase of BL application as concentration dependent manner. Consistently, GUS activity and transcript level of ACO4 were decreased and increased by application of BL and BRZ, respectively. pACO4-GUS was mainly observed in shoot, especially vascular tissue, true leaf, stomata and trichome, implying that ACO4 exert its function in the tissues. In bzr1-1D, ACO4 transcript level was decreased, but was not changed in bes1-D. EMSA revealed that only BZR1 bound to BRRE sequence in putative promoter region of ACO4, indicating that BZR1 directly regulates expression of ACO4 in A. thaliana. ACO4 over-expressed mutant, 35S-ACO4 showed short hypocotyls than wild type. 35S-ACO4 transgenic plants were rescued by application of an ethylene biosynthesis inhibitor, cobalt ion, implicating that ACO4 inhibits hypocotyl elongation of Arabidopsis. These results suggest that BRs control Arabidopsis shoot growth through decreased level of ACO4 in A. thaliana.
Conclusively, BRs control endogenous level of ABA and ethylene by direct binding of BR transcription factors (BES1 and BZR1) to promoters in ABA and ethylene biosynthetic genes (ABA2 and ACO4), which regulates seed germination and shoot growth in Arabidopsis plants.

목차 Contents

• 표지 ... 1
• 제출문 ... 2
• 요약문 ... 3
• SUMMARY ... 5
• 목차 ... 7
• 제1장 서 론 ... 8
• 제1절 식물 호르몬 상호작용 ... 8
• 제2절 Brassinosteroids (BRs) ... 10
• 제2장 국내외 기술개발 현황 ... 13
• 제1절 국내 연구 현황 ... 13
• 제2절 국외 연구 현황 ... 13
• 제3절 국내외 연구현황 비교 및 필요 연구 분야 ... 13
• 제3장 연구개발수행 내용 및 결과 ... 15
• 제1절 BRs 전사인자 BES1에 의한 A BA 생합성 유전자 ABA2의 조절기작 ... 15
• 제2절 BRs 전사인자 BES1에 의한 ethylene 생합성 유전자 ACOs의 조절기작 ... 21
• 제4장 연구개발목표 달성도 및 대외기여도 ... 25
• 제1절 목표대비 달성도 ... 25
• 제2절 정량적 성과 ... 25
• 제5장 연구개발결과의 활용계획 ... 27
• 제6장 연구개발과정에서 수집한 해외과학기술정보 ... 28
• 제7장 기타 중요 변동사항 ... 29
• 제8장 국가과학기술종합정보시스템에 등록한 연구장비 현황 ... 30
• 제9장 참고문헌 ... 31
• <참고> 주요 연구성과 요약 ... 34
• 주요 결과 요약서 ... 35