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벼 WRKY 전사인자들의 환경 스트레스 저항성 조절 기작연구 원문보기

  • 저자

    한무호

  • 학위수여기관

    경희대학교

  • 학위구분

    국내박사

  • 학과

    생명공학원-유전공학전공

  • 지도교수

  • 발행년도

    2013

  • 총페이지

    80p.

  • 키워드

    Crop plants, environmental stresses, development, resistance, rice WRKY;

  • 언어

    eng

  • 원문 URL

    http://www.riss.kr/link?id=T13238605&outLink=K  

  • 초록

    식물의 광범위 스트레스 저항성 기작에 대한 연구는 수확량의 증산 뿐만이 아니라 재배 인력 및 농약의 사용에 대한 의존도를 낮추어 고령화 되어가는 농업구조에서 파생되는 인력부족 및 농약에 의한 환경 오염을 줄일 수 있는 근본적인 대안으로 기대되고 있다. 식물에서 독특하게 진화한 것으로 확인 된 WRKY 전사조절인자를 분석하고, 식물대사 및 광범위 병 저항성 신호전달에 관여하는 WRKY 유전자들을 집중 분석 함으로써 근본적인 대안을 확보하고자 하였다. 전사조절인자로써 식물 특이적으로 진화에 성공한 WRKY 단백질은 애기장대에서는 70여개가, 벼에서는 100여개 이상이 super family를 이루는 것으로 보고되었으며, 식물의 상처, 다양한 병원균 감염 및 병방어 호르몬들의 변화 혹은 병 방어 신호 감지 시, 그리고 잎의 노화 및 스트레스 등에 의해서 유전자의 발현이 유도 혹은 감소 되는 것으로 확인 하였다. 다양한 환경 스트레스 및 병 처리 조건에서 OsWRKY 유전자들의 발현 양상을 확인하고 특징들을 정리 하였으며, 일부 벼의 광범위 저항성에 관련 될 것으로 예상된 OsWRKY 유전자를 형질전환시킨 벼의 경우, 환경 스트레스 저항성 및 병 저항성이 증대됨을 확인 하였다. 또한 노화 특이적인 발현을 보이는 OsWRKY들의 노화 조절 기작에 직접 관여함도 확인 하였으며, 환경 스트레스 및 병 저항성이 증대되고 노화 조절이 최적화된 품종의 벼를 개발 후 재배 할 경우 수확량의 증대로 이어질 것으로 기대한다. 또한 세계 인류의 유용 작물 중 하나인 벼에서 축적된 생물학적 연구 성과는 다른 모든 곡류 등에서도 기술 접목이 가능하기에 매우 가치 있게 조명될 것으로 기대된다.


    Crop plants are subject of environmental stresses that adversely affect of development and disease resistance. In the evolution, plants have developed mechanisms to adapt of biotic and abiotic stresses. Plants have produced various immune responses to against them from infection with microbial pathogens. At least two distinct mechanisms of pathogen recognition and defense response are used by plants. The first course, plants percept pathogen-associated molecular patterns (PAMPs) are dependent activation of PAMP-triggered immunity (PTI) by pattern recognition receptors. PTI is often mean it for basal defense and to limit growth of pathogens. As the second branch, the recognition of pathogen effectors through host sensors encoded by disease resistance (R) genes induces effector-triggered immunity (ETI). ETI is a strong immune response and accelerate that efficiently protects plants to PTI from specific strains or races of pathogens. Systemic acquired resistance (SAR) is an induced broad spectrum resistance mechanism in plants. In contrast to ETI, SAR can also conferred immune memory in plants, that is not associated with programmed cell death (PCD). In higher plants, PCD regulates the response of plants to HR with host developmental processes. For example, stamen or ovary, and megaspore abortion during the flower and seed formation, tapetal and aleurone layer degradation with endosperm degradation (in monocotyledons), tracheary element differentiation, aerenchyma formation, death of root cap, leaf senescence, etc. Leaf senescence associated cell death as a PCD, and controlled by age or many active genetic programs. Reactive oxygen species (ROS) have recognized as a major signaling molecule in the PCD response, and may be promote by ROS accumulation. Gene-expression studies of ROS-generating and -scavenging enzymes have demonstrated that environmental stresses share substantial similarities in PCD regulation. Abiotic stressors can also have limits plant performance and productivity. For example, most types of abiotic stresses (temperature, intense light, and water deficit stresses) have effect the cellular redox homeostasis and enhance production of soluble sugars and ROS. Plants frequently adjust soluble sugars and ROS levels by a diversified network of metabolism, generating and scavenging enzymes with antioxidants. Soluble sugars (glucose, fructose and sucrose), play a major role in plant structure and control the ROS balance. Soluble sugars starvation event has been shown to activate ROS scavenging genes, such as catalase. Several proteins of ROS-mediated signaling are also directly or indirectly regulators of abiotic stress responses. Powerful antioxidative enzymes (catalase, peroxidases, superoxide dismutase (SOD), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR)) and antioxidants (ascorbate, glutathione, a-tocopherol, carotenoids, flavonoids, and metallothioneins (MTs)) are can regulate to ROS level by scavenge various ROS. Interaction of ROS with the other plant signaling molecules such as plant hormones are also key determinants of ROS signaling. Plant hormones are small molecular weight compounds and key players in plant physiology, development and defense from embryogenesis to senescence. Plant hormones are also central signaling regulators of stresses. The sensing of biotic and abiotic stresses induces that accumulation of plant hormones. Identification of plant hormones are including auxins, cytokinins (CKs), gibberellins (GAs), brassinosteroids, strigolactones, abscisic ascid (ABA), ethylene, salicylic acid (SA), and jasmonate (JA). These signaling molecules have structurally and chemically diverse role in plant. There are several types of plant hormone which stimulates or inhibits the growth and defense of plants, and interaction can be another determinant of ROS signaling. For instance, auxin, ABA and JA together with ROS regulate diverse processes such as physiological development, stomatal closure and wounding responses. CKs provides a program to specifically manipulate the senescence of the plant immune system and regulates leaf senescence. SA is also modulation of resistance responses to biotic and abiotic stresses. In our present study, we characterized three of the members of a key regulatory rice WRKY gene. OsWRKY30 has functions as a positive regulator of rice disease resistance via an SA signaling pathway. OsWRKY42 is a positive controller of senescence by indirect suppression of ROS scavenging genes in rice. Also, overexpression of OsWRKY2 alters rice morphology and cytokinin metabolism. These results suggest that OsWRKYs are important for its biological rules in defense responses to biotic and abiotic stresses


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