Kiba Akinori, Lee Kyon-Ye, Ohnishi Kouhei, Hikichi Yasufumi
Laboratory of Plant Pathology and Biotechnology, Faculty of Agriculture, Kochi University, Nankoku 783-8502, Japan.
J Plant Physiol. 2008 Nov 28;165(17):1757-73. doi: 10.1016/j.jplph.2007.10.010. Epub 2008 Jan 2.
The development of bacterial rot disease caused by Pseudomonas cichorii is closely associated with programmed cell death. To investigate the molecular events occurring during the development of bacterial rot, we isolated 20 P. cichorii-responsive genes (PcRGs) in lettuce by differential display. Among these PcRGs, signal transduction-, transcription/translation- and defense/stress responses-related PcRGs were subjected to a comparative expression study. We used RNA samples isolated from lettuce leaves inoculated with P. cichorii and hypersensitive response-inducing Pseudomonas syringae pv. syringae. Expression of PcRG1-5-5 (spliceosomal protein), 2-9-2 (protein kinase) and 1-6-2 (ACC oxidase), 7-5 (alternative oxidase) and BI-I (bax inhibitor I) significantly increased in lettuce leaves inoculated with both P. cichorii and P. syringae pv. syringae. Intriguingly, PcRG 1-2-6 (protein phosphatase 2C) and 4-D-5 (protein kinase) were only up-regulated in P. cichorii-inoculated lettuce, whereas expression of PcRG1-3-2 (ribonucleoprotein) was only enhanced in P. syringae pv. syringae-inoculated lettuce. Expressions of PcRG1-3-2, 1-5-5, 1-6-2, 2-9-2, 7-5 and BI-I were induced by treatments with salicylic acid and/or methyl jasmonate. However, expression of PcRG1-2-6 and 4-D-5, which were specifically up-regulated by P. cichorii, were scarcely affected by these chemicals. Pharmacological studies suggested that ethylene and alternative oxidase were commonly related to disease development and hypersensitive responses. By contrast, there may be a different role for protein synthesis and protein kinase during disease development and in hypersensitive responses. These results suggested the overall similarity of genes expressed during disease development and in hypersensitive responses. However, there were differences not only in induction kinetics and the level of gene expression but also in the signal transduction pathway between hypersensitive responses and disease development.
由菊苣假单胞菌引起的细菌性软腐病的发展与程序性细胞死亡密切相关。为了研究细菌性软腐病发展过程中发生的分子事件，我们通过差异显示技术在生菜中分离出20个菊苣假单胞菌响应基因（PcRGs）。在这些PcRGs中，对与信号转导、转录/翻译以及防御/应激反应相关的PcRGs进行了比较表达研究。我们使用了从未接种菊苣假单胞菌以及接种了能诱导过敏反应的丁香假单胞菌丁香致病变种的生菜叶片中分离得到的RNA样本。在同时接种了菊苣假单胞菌和丁香假单胞菌丁香致病变种的生菜叶片中，PcRG1-5-5（剪接体蛋白）、2-9-2（蛋白激酶）、1-6-2（ACC氧化酶）、7-5（交替氧化酶）和BI-I（bax抑制剂I）的表达显著增加。有趣的是，PcRG 1-2-6（蛋白磷酸酶2C）和4-D-5（蛋白激酶）仅在接种菊苣假单胞菌的生菜中上调，而PcRG1-3-2（核糖核蛋白）的表达仅在接种丁香假单胞菌丁香致病变种的生菜中增强。水杨酸和/或茉莉酸甲酯处理可诱导PcRG1-3-2、1-5-5、1-6-2、2-9-2、7-5和BI-I的表达。然而，由菊苣假单胞菌特异性上调的PcRG1-2-6和4-D-5的表达几乎不受这些化学物质的影响。药理学研究表明，乙烯和交替氧化酶通常与疾病发展和过敏反应有关。相比之下，蛋白质合成和蛋白激酶在疾病发展和过敏反应中可能具有不同的作用。这些结果表明疾病发展过程中表达的基因与过敏反应中表达的基因总体相似。然而，不仅在诱导动力学和基因表达水平上存在差异，而且在过敏反应和疾病发展之间的信号转导途径上也存在差异。
