Robb Jane, Shittu Hakeem, Soman Kizhake V, Kurosky Alexander, Nazar Ross N
Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
Planta. 2012 Aug;236(2):623-33. doi: 10.1007/s00425-012-1637-7. Epub 2012 Apr 6.
Although the hypersensitive reaction in foliar plant diseases has been extensively described, little is clear regarding plant defense strategies in vascular wilt diseases affecting numerous economically important crops and trees. We have examined global genetic responses to Verticillium wilt in tomato (Lycopersicon esculentum Mill.) plants differing in Ve1 resistance alleles. Unexpectedly, mRNA analyses in the susceptible plant (Ve1-) based on the microarrays revealed a very heroic but unsuccessful systemic response involving many known plant defense genes. In contrast, the response is surprisingly low in plants expressing the Ve1+ R-gene and successfully resisting the pathogen. Similarly, whole-cell protein analyses, based on 2D gel electrophoresis and mass spectrometry, demonstrate large systemic increases in a variety of known plant defense proteins in the stems of susceptible plants but only modest changes in the resistant plant. Taken together, the results indicate that the large systemic increases in plant defense proteins do not protect the susceptible plant. Indeed, since a number of the highly elevated proteins are known to participate in the plant hypersensitive response as well as natural senescence, the results suggest that some or all of the disease symptoms, including ultimate plant death, actually may be the result of this exaggerated plant response.
尽管植物叶部病害中的过敏反应已被广泛描述，但对于影响众多经济作物和树木的维管束萎蔫病，植物的防御策略仍知之甚少。我们研究了番茄（Lycopersicon esculentum Mill.）中不同Ve1抗性等位基因对黄萎病的整体遗传反应。出乎意料的是，基于微阵列对感病植株（Ve1-）进行的mRNA分析显示，其存在一种非常强烈但未成功的系统反应，涉及许多已知的植物防御基因。相比之下，表达Ve1+抗性基因并成功抵御病原体的植株的反应却出奇地低。同样，基于二维凝胶电泳和质谱分析的全细胞蛋白质分析表明，感病植株茎中多种已知植物防御蛋白出现大量系统性增加，而抗病植株中只有适度变化。综合来看，结果表明植物防御蛋白的大量系统性增加并不能保护感病植株。实际上，由于已知一些高度上调的蛋白质既参与植物过敏反应，也参与自然衰老，结果表明部分或所有病害症状，包括最终植株死亡，实际上可能是这种过度的植物反应所致。
