Rizhsky L, Mittler R
Department of Plant Sciences, The Hebrew University of Jerusalem, Israel.
Plant Mol Biol. 2001 Jun;46(3):313-23. doi: 10.1023/a:1010617220067.
The development of new strategies to enhance resistance of plants to pathogens is instrumental in preventing agricultural losses. Lesion mimic, the spontaneous formation of lesions resembling hypersensitive response lesions in the absence of a pathogen, is a dramatic phenotype occasionally induced upon expression of certain transgenes in plants. These transgenes simulate the presence of a pathogen and, therefore, activate the plant anti-pathogen defense mechanisms and induce a state of systemic resistance. Lesion mimic genes have been successfully used to enhance the resistance of a number of different plants to pathogen attack. However, constitutive expression of these genes in plants is associated with the spontaneous formation of lesions on leaves and stems, reduced growth, and lower yield. We tested the possibility of using a wound-inducible promoter to control the expression of bacterio-opsin (bO), a transgene that confers a lesion mimic phenotype in tobacco and tomato plants when constitutively expressed. We found that plants with inducible expression of bO did not develop spontaneous lesions. Nevertheless. under controlled laboratory conditions, they were found to be resistant to infection by pathogens. The activation of defense mechanisms by the bO gene was not constitutive, and occurred in response to wounding or pathogen infection. Furthermore, wounding of transgenic tobacco plants resulted in the induction of systemic resistance to pathogen attack within 48 h. Our findings provide a promising initial assessment for the use of wound-inducible promoters as a new strategy to enhance pathogen resistance in transgenic crops by means of lesion mimic genes.
开发新的策略以增强植物对病原体的抗性有助于防止农业损失。病变模拟是指在没有病原体的情况下自发形成类似过敏反应病变的现象，是在植物中表达某些转基因时偶尔诱导出的一种显著表型。这些转基因模拟病原体的存在，从而激活植物的抗病原体防御机制并诱导系统抗性状态。病变模拟基因已成功用于增强多种不同植物对病原体攻击的抗性。然而，这些基因在植物中的组成型表达与叶片和茎上自发形成病变、生长受抑制以及产量降低有关。我们测试了使用伤口诱导型启动子来控制细菌视紫红质（bO）表达的可能性，bO是一种转基因，在组成型表达时会使烟草和番茄植株呈现病变模拟表型。我们发现bO诱导表达的植株不会自发形成病变。然而，在受控的实验室条件下，它们被发现对病原体感染具有抗性。bO基因对防御机制的激活不是组成型的，而是在受到伤口或病原体感染时发生。此外，转基因烟草植株受伤后在48小时内会诱导出对病原体攻击的系统抗性。我们的研究结果为利用伤口诱导型启动子作为一种通过病变模拟基因增强转基因作物病原体抗性的新策略提供了有前景的初步评估。
