Véronési C, Rickauer M, Fournier J, Pouénat M L, Esquerré-Tugayé M T
Centre de Physiologie Végétale, Unité Mixte de Recherche Centre National de la Recherche, Scientifique Université Paul Sabatier 5546, Université Paul Sabatier, Toulouse, France.
Plant Physiol. 1996 Nov;112(3):997-1004. doi: 10.1104/pp.112.3.997.
A recently isolated cDNA clone of tobacco (Nicotiana tabacum L.) lipoxygenase (LOX) was used to study LOX gene expression in tobacco cell-suspension cultures and intact plants in response to infection with Phytophthora parasitica nicotianae (Ppn). Southern blot analysis of tobacco DNA indicated that only a small number of LOX genes hybridize to this probe. These genes were not constitutively expressed to a detectable level in control cells and healthy plants. In contrast, a rapid and transient accumulation of transcripts occurred in cells and plants after treatment with elicitor and inoculation with zoospores of Ppn, respectively. In cell cultures LOX gene expression could also be induced by linolenic acid, a LOX substrate, and by methyl jasmonate, one of the products derived from the action of LOX on linolenic acid. In the infection assays, LOX gene expression and enzyme activity were observed earlier when the plants carried a resistance gene against the race of Ppn used for inoculation. The differential expression of LOX during the race-cultivar-specific interaction between tobacco and Ppn, as well as its regulation by elicitors and jasmonate, suggest a role of LOX in plant resistance and establishment of the defense status against this pathogen.
利用最近分离得到的烟草（Nicotiana tabacum L.）脂氧合酶（LOX）的cDNA克隆，研究烟草细胞悬浮培养物和完整植株中LOX基因在受到寄生疫霉烟草专化型（Ppn）侵染时的表达情况。对烟草DNA进行的Southern杂交分析表明，只有少数LOX基因与该探针杂交。这些基因在对照细胞和健康植株中未组成性表达至可检测水平。相反，在用激发子处理细胞以及用Ppn游动孢子接种植株后，转录本分别迅速且短暂地积累。在细胞培养物中，LOX基因表达也可由LOX底物亚麻酸以及LOX作用于亚麻酸产生的产物之一茉莉酸甲酯诱导。在感染试验中，当植株携带针对用于接种的Ppn小种的抗性基因时，更早观察到LOX基因表达和酶活性。在烟草与Ppn的小种-品种特异性互作过程中LOX的差异表达，以及其受激发子和茉莉酸的调控，表明LOX在植物抗性以及针对该病原菌建立防御状态中发挥作用。
