Defence reactions in the apoplastic proteome of oilseed rape (Brassica napus var. napus) attenuate Verticillium longisporum growth but not disease symptoms
Defence reactions in the apoplastic proteome of oilseed rape (Brassica napus var. napus) attenuate Verticillium longisporum growth but not disease symptoms
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DOI：
10.1186/1471-2229-8-129
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发表时间：
2008-12-18
影响因子：
5.3
通讯作者：
Polle, Andrea
中科院分区：
文献类型：
--
作者：
Floerl, Saskia;Druebert, Christine;Polle, Andrea
背景：黄萎病是十字花科植物最重要的病原菌之一，在其发育的大部分阶段都严格存在于木质部中。有人认为，疾病症状与木质部导管堵塞有关。本研究旨在研究长孢霉在甘蓝型油菜木质部汁液和叶质外体中诱导的细胞外防御反应。结果：长孢霉(VL43)侵染后3周才通过下胚轴屏障，植株表现出较大的茎发育迟缓和叶片轻度黄化。在侵染初期，VL43侵染植株与未侵染植株相比，叶片的光合碳同化作用、蒸腾速率和营养元素含量没有受到影响。叶质外体蛋白质组分析显示，经2-D蛋白分离后有170个斑点，其中12个斑点在VL43-侵染后显著增强。LS-MS/MS分析和数据库搜索发现VL43响应蛋白与内切酶、过氧化物酶、PR-4蛋白和β-1，3-葡聚糖酶相匹配。在木质部汁液中发现了三种上调蛋白，其中两种被鉴定为PR-4和β-1，3-葡聚糖酶。感染植株的木质部汁液对长孢霉的生长有抑制作用。结论：长孢霉的侵染不会造成干旱胁迫或营养限制。因此，发育迟缓和轻度黄化并不是由于VL43引起的木质部受阻而导致的水和养分供应不足的后果。一组不同的胞外PR蛋白被激活，这可能限制了黄萎病在下胚轴上的扩散。计算机分析表明，乙烯参与了VL43反应蛋白的上调。
Background: Verticillium longisporum is one of the most important pathogens of Brassicaceae that remains strictly in the xylem during most stages of its development. It has been suggested that disease symptoms are associated with clogging of xylem vessels. The aim of our study was to investigate extracellular defence reactions induced by V. longisporum in the xylem sap and leaf apoplast of Brassica napus var. napus in relation to the development of disease symptoms, photosynthesis and nutrient status.Results: V. longisporum (strain VL43) did not overcome the hypocotyl barrier until 3 weeks after infection although the plants showed massive stunting of the stem and mild leaf chlorosis. During this initial infection phase photosynthetic carbon assimilation, transpiration rate and nutrient elements in leaves were not affected in VL43-infected compared to non-infected plants. Proteome analysis of the leaf apoplast revealed 170 spots after 2-D-protein separation, of which 12 were significantly enhanced in response to VL43-infection. LS-MS/MS analysis and data base searches revealed matches of VL43-responsive proteins to an endochitinase, a peroxidase, a PR-4 protein and a beta-1,3-glucanase. In xylem sap three up-regulated proteins were found of which two were identified as PR-4 and beta-1,3-glucanase. Xylem sap of infected plants inhibited the growth of V. longisporum.Conclusion: V. longisporum infection did not result in drought stress or nutrient limitations. Stunting and mild chlorosis were, therefore, not consequences of insufficient water and nutrient supply due to VL43-caused xylem obstruction. A distinct array of extracellular PR-proteins was activated that might have limited Verticillium spreading above the hypocotyl. In silico analysis suggested that ethylene was involved in up-regulating VL43-responsive proteins.