Keller H, Pamboukdjian N, Ponchet M, Poupet A, Delon R, Verrier J L, Roby D, Ricci P
Institut National de la Recherche Agronomique (INRA), Station de Botanique et de Pathologie Végétale, BP 2078, F-06606 Antibes Cedex, France.
Plant Cell. 1999 Feb;11(2):223-35. doi: 10.1105/tpc.11.2.223.
The rapid and effective activation of disease resistance responses is essential for plant defense against pathogen attack. These responses are initiated when pathogen-derived molecules (elicitors) are recognized by the host. We have developed a strategy for creating novel disease resistance traits whereby transgenic plants respond to infection by a virulent pathogen with the production of an elicitor. To this end, we generated transgenic tobacco plants harboring a fusion between the pathogen-inducible tobacco hsr 203J gene promoter and a Phytophthora cryptogea gene encoding the highly active elicitor cryptogein. Under noninduced conditions, the transgene was silent, and no cryptogein could be detected in the transgenic plants. In contrast, infection by the virulent fungus P. parasitica var nicotianae stimulated cryptogein production that coincided with the fast induction of several defense genes at and around the infection sites. Induced elicitor production resulted in a localized necrosis that resembled a P. cryptogea-induced hypersensitive response and that restricted further growth of the pathogen. The transgenic plants displayed enhanced resistance to fungal pathogens that were unrelated to Phytophthora species, such as Thielaviopsis basicola, Erysiphe cichoracearum, and Botrytis cinerea. Thus, broad-spectrum disease resistance of a plant can be generated without the constitutive synthesis of a transgene product.
疾病抗性反应的快速有效激活对于植物抵御病原体攻击至关重要。当宿主识别出病原体衍生分子（激发子）时，这些反应就会启动。我们开发了一种创造新的抗病性状的策略，即转基因植物通过产生激发子对毒性病原体的感染作出反应。为此，我们培育了转基因烟草植株，其携带病原体诱导型烟草hsr 203J基因启动子与编码高活性激发子隐地蛋白的隐地疫霉基因之间的融合基因。在未诱导的条件下，转基因处于沉默状态，在转基因植物中检测不到隐地蛋白。相反，毒性真菌烟草寄生疫霉的感染刺激了隐地蛋白的产生，这与感染部位及其周围几个防御基因的快速诱导同时发生。诱导产生的激发子导致局部坏死，类似于隐地疫霉诱导的超敏反应，并限制了病原体的进一步生长。转基因植物对与疫霉属物种无关的真菌病原体，如烟草黑胫病菌、瓜白粉菌和灰葡萄孢菌，表现出增强的抗性。因此，无需组成型合成转基因产物就可以产生植物的广谱抗病性。
