Abad M S, Hakimi S M, Kaniewski W K, Rommens C M, Shulaev V, Lam E, Shah D M
Monsanto Company, Chesterfield, MO 63198, USA.
Mol Plant Microbe Interact. 1997 Jul;10(5):635-45. doi: 10.1094/MPMI.1997.10.5.635.
The lesion-mimic mutants of certain plants display necrotic lesions resembling those of the hypersensitive response and activate local and systemic defense responses in the absence of pathogens. We have engineered a lesion-mimic phenotype in transgenic Russet Burbank potato plants through constitutive expression of a bacterio-opsin (bO) proton pump derived from Halobacterium halobium. Transgenic potato plants exhibiting a lesion-mimic phenotype had increased levels of salicylic acid and overexpressed several pathogenesis-related messenger RNAs, all hallmarks of systemic acquired resistance (SAR). The lesion-mimic plants also displayed enhanced resistance to the US1 isolate (A1 mating type) of a fungal pathogen, Phytophthora infestans, a causal agent of late blight disease. In contrast, little resistance was observed against the US8 isolate (A2 mating type) of this pathogen. Furthermore, a majority of the transgenic plants displaying the lesion-mimic phenotype had increased susceptibility to potato virus X. The tubers of these plants were not resistant to the bacterial pathogen Erwinia carotovora. These results indicate that expression of bO can result in the activation of defense responses in transgenic potato plants and show for the first time that bO expression can confer resistance to a pathogenic fungus. However, our results also demonstrate that like SAR, this "engineered" resistance is likely to be limited to certain pathogens and particular cultivars.
某些植物的病变模拟突变体表现出类似于过敏反应的坏死病变，并在没有病原体的情况下激活局部和系统防御反应。我们通过组成型表达源自嗜盐菌的细菌视紫红质（bO）质子泵，在转基因褐皮伯班克马铃薯植株中构建了病变模拟表型。表现出病变模拟表型的转基因马铃薯植株水杨酸水平升高，几种病程相关信使核糖核酸过度表达，这些都是系统获得性抗性（SAR）的标志。病变模拟植株对真菌病原体致病疫霉的US1分离株（A1交配型）也表现出增强的抗性，致病疫霉是晚疫病的病原体。相比之下，对该病原体的US8分离株（A2交配型）几乎没有抗性。此外，大多数表现出病变模拟表型的转基因植株对马铃薯X病毒的易感性增加。这些植株的块茎对细菌病原体胡萝卜软腐欧文氏菌没有抗性。这些结果表明，bO的表达可导致转基因马铃薯植株中防御反应的激活，并首次表明bO的表达可赋予对致病真菌的抗性。然而，我们的结果也表明，与SAR一样，这种“工程化”抗性可能仅限于某些病原体和特定品种。
