초록 ▼

○ estradiol inducible system을 이용하여 avrRpt2에 의한 RPM1 분해를 유도할 수 있는 시스템 확립
○ NBS domain을 대량발현하여 endogenous한 NBS-LRR 형태의 저항성 유전자의 기능을 특이적 저해하는 방법개발
- CC-NBS-LRR 형태의 저항성 유전자들은 특이적으로 저해되나 TIR-NBS-LRR 유전자는 저해되지 안음을 밝힘. NBS domain 중에서 Kinase 2a subdomain이 필수적임을 밝힘 RIN4의 분해가 AvrRpt2에 의한 AvrRpml/RPM1 저

○ estradiol inducible system을 이용하여 avrRpt2에 의한 RPM1 분해를 유도할 수 있는 시스템 확립
○ NBS domain을 대량발현하여 endogenous한 NBS-LRR 형태의 저항성 유전자의 기능을 특이적 저해하는 방법개발
- CC-NBS-LRR 형태의 저항성 유전자들은 특이적으로 저해되나 TIR-NBS-LRR 유전자는 저해되지 안음을 밝힘. NBS domain 중에서 Kinase 2a subdomain이 필수적임을 밝힘 RIN4의 분해가 AvrRpt2에 의한 AvrRpml/RPM1 저항성 신호전달체계를 방해현상과 RPM1-myc단백질이 HR 없이 분해되는 현상에 관여함을 밝힘.
○ 동량의 AvrRpml 과 AvrRpt2가 식물세포로 전이되면 적어도 2배 이상의 빨리 AvrRpt 가 AvrRpml에 의한 RIN4 phosphorylation에 앞서서 RIN4를 분해하기 때문에 AvrRpt2가 AvrRpml/RPM에 의한 저항성 반응을 방해하는 현상이 일어난다는 것을 밝혔다.
○ Pst(avrRpt2)를 직접 감염하는 3차 test에서 현재 10개의 ner (no elimination of RPM1 by AvrRpt2)mutant 분리. 9개의 nerl mutants는 AvrRpt2에 의해 RIN4 분해되나 RPM1 둘 다 분해 안됨.

Abstract ▼

To defend themselves against infection by pathogens, plants must recognize invading pathogens and actively respond. This resistance mechanism is often explained at the genetic level by gene(avr)-for-gene(R) model. However, its molecular working mechanism are poorly understood. By using isogenic P.sy

To defend themselves against infection by pathogens, plants must recognize invading pathogens and actively respond. This resistance mechanism is often explained at the genetic level by gene(avr)-for-gene(R) model. However, its molecular working mechanism are poorly understood. By using isogenic P.syringae strains and Arabidopsis mutants that differ only specific avirulence genes and resistance genes, respectively, we investigated what happens when two avirulence signals are delivered simultaneously to plant. Our results showed that AvrRpt2 not only interfered with AvrRpml/RPM1-mediated resistance signal but also induced degradation of RPM1 protein. However, disappearance of RPM1 is not a direct cause for interference of AvrRpml/RPM1-mediated resistance signal by AvrRpt2, because RPM1 protein was not completely degraded at the time point when AvrRpt2 interferes with AvrRpm1/RPM1-mediated resistance signal. It is likely that AvrRpt2 targets and eliminates RIN4 prior to phosphorylation of RIN4 by avrRpm1 that is required for activation of RPM1. As a result, AvrRpt2 preventing from action of AvrRpm1 equally delivered to plant cell.
We also developed screening method and identified mutants that are deficient in AvrRpt2-mediated RPM1 degradation. We found two kinds of ner (no elimination of RPM1 by AvrRpt2) mutants. RIN4 was eliminated by AvrRpt2 but not RPM1 in ner1 mutant. However, AvrRpt2 can eliminate neither RIN4 nor RPM1 in ner2 mutant. These mutants will be useful to shed light on the possible role of protein degradation in the signal transduction of plant resistance.
The great majority of R genes in plants are NBS-LRR type. NBS-LRR type R genes are subgrouped to CC type and TIR type depending on domain at the N terminus. These R genes use different signalling pathway to activate defense response after recognition of invading pathogens. To develope a method that specifically inhibits functions of endogenous NBS-LRR type R genes, we investigated the dominant negative effects by overexpressing specific domains of well-studied two different group of NBS-LRR type R genes, CC type (RPM1, RPS2, and RPS5) and TIR type (RPS4). Our results clearly demonstrated that overexpression of NBS domain of RPM1, RPS2, and RPS5 effectively inhibited the endogenous RPM1, RPS2, and RPS5 gene functions in Arabidopsis Col-o. However, RPS4 was not affected with overexpression of NBS domain of RPS4, indicating that the working mechanism of TIR type NBS-LRR protein is different from that of CC type NBS-LRR protein. The dominant negative effect of CC type NBS-LRR proteins by overexpression of NBS domain may result from inhibition of dimerization that may be active form to recognize avr gene product or activate defense response. Furthermore, serial deletion of NBS domain showed that kinase la subdomain of NBS is essential for dominant negative effect. This method will be very useful to induce loss of function of endogenous NBS-LRR type R genes in rice because complete genomic sequence of rice revealed that rice has only CC type NBS-LRR genes.

목차 Contents

• 식물 병원균 저항성에 관여하는 NBS-LRR 형태의 저항성 유전자들의 생화학적 분자유전학적 연구...1
• 제출문...2
• 보고서초록...3
• 요약문...6
• SUMMARY...9
• CONTENTS...11
• 목차...12
• 제 1 장 연구개발과제의 개요...13
• 제 2 장 국내외 기술개발 현황...17
• 제 3 장 연구개발수행 내용 및 결과...20
• 제 4 장 목표달성도 및 관련분야에의 기여도...37
• 제 5 장 연구개발결과의 활용계획...40
• 제 6 장 연구개발과정에서 수집한 해외과학기술정보...41
• 제 7 장 참고문헌...42