Fauconnier Marie-Laure, Rojas-Beltran Jorge, Dupuis Brice, Delaplace Pierre, Frettinger Patrick, Gosset Virginie, du Jardin Patrick
Plant Biology Unit, Gembloux Agricultural University, Passage des Déportés 2, 5030 Gembloux, Belgium.
Plant Physiol Biochem. 2008 Aug-Sep;46(8-9):823-31. doi: 10.1016/j.plaphy.2008.04.010. Epub 2008 Apr 23.
Oxylipins constitute a class of molecules notably involved in host-pathogen interactions. In the potato-Phytophthora infestans (Mont.) De Barry (P. infestans) relationships, the role of colneleic and colnelenic acids, two oxylipins resulting from the consecutive action of lipoxygenase (EC 1.13.11.12) and divinyl ether synthase (EC 1.-) on respectively linoleic and linolenic acids have been previously reported. In the present paper, five potato cultivars with contrasting resistance to P. infestans were submitted to infection. Lipoxygenase pathway response was studied at both transcriptional and metabolic levels. A Northern blot preliminary study revealed that lipoxygenase (lox1 and lox3) and divinyl ether synthase genes were clearly up-regulated 96h after leaf inoculation with P. infestans. Profiling of free and esterified oxylipins performed 24h, 48h, 72h and 96h after inoculation, showed that esterified oxylipins are mainly produced with 9-derivatives in higher concentrations (esterified forms of colnelenic acid, 9-hydroxy octadecatrienoic acid, 9-hydroperoxy octadecatrienoic acid). Oxylipin accumulation is undetectable 24h after infection, slightly detectable after 48h, reaching highest concentrations after 96h. Cultivars show slightly different oxylipin profiles but the concentration of individual oxylipins differs markedly 96h after infection. No correlation was found between P. infestans resistance levels and oxylipin synthesis rates or concentration. To assess local and systemic effects of colneleic acid application before P. infestans infection, Bintje cultivar was sprayed with colneleic acid 72h before inoculation. Both application modes (local and systemic) resulted in lipoxygenase pathway activation without affecting the resistance level to the pathogen.
氧脂素是一类在宿主 - 病原体相互作用中显著发挥作用的分子。在马铃薯 - 致病疫霉（Mont.）德巴里（致病疫霉）的关系中，先前已有报道9,12 - 十八碳二烯酸和9,12,15 - 十八碳三烯酸这两种氧脂素的作用，它们分别是脂氧合酶（EC 1.13.11.12）和二乙烯基醚合酶（EC 1.-）对亚油酸和亚麻酸连续作用产生的。在本文中，对五个对致病疫霉具有不同抗性的马铃薯品种进行了感染处理。在转录和代谢水平上研究了脂氧合酶途径的反应。一项Northern印迹初步研究表明，在用致病疫霉接种叶片96小时后，脂氧合酶（lox1和lox3）和二乙烯基醚合酶基因明显上调。在接种后24小时、48小时、72小时和96小时对游离和酯化氧脂素进行分析，结果表明酯化氧脂素主要以9 - 衍生物的形式产生，且浓度较高（9,12,15 - 十八碳三烯酸的酯化形式、9 - 羟基十八碳三烯酸、9 - 氢过氧十八碳三烯酸）。感染后24小时未检测到氧脂素积累，48小时后略有检测到，96小时后达到最高浓度。不同品种的氧脂素谱略有不同，但感染96小时后单个氧脂素的浓度差异显著。未发现致病疫霉抗性水平与氧脂素合成速率或浓度之间存在相关性。为了评估在致病疫霉感染前施用9,12 - 十八碳二烯酸的局部和全身效应，在接种前72小时用9,12 - 十八碳二烯酸喷洒宾杰品种。两种施用方式（局部和全身）均导致脂氧合酶途径激活，而不影响对病原体的抗性水平。
