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1.
A phytotoxic extract from Pinus sylvestris infected with Bursaphelenchus xylophilus inhibited growth of the blue-strain fungus Ceratocystis ips and caused temporary paralysis in vitro of B. xylophilus. Although the nematodes recovered from paralysis, final population size of B. xylophilus was suppressed by the toxin. Extracts from noninfected P. sylvestris affected neither the fungus nor the nematode.  相似文献   

2.
茄科植保素的研究进展   总被引:2,自引:1,他引:1  
本文综述了茄科植保素的种类、分布、提取、检测和诱导,并对茄科植保素的研究进行了展望。  相似文献   

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Rice (Oryza sativa L.) produces a variety of diterpene phytoalexins, such as momilactones, phytocassanes, and oryzalexins. Momilactone B was previously identified as an allelopathic substance exuded from the roots of rice. We identified in this present study momilactone A and phytocassanes A–E in extracts of, and exudates from, the roots of rice seedlings. The concentration of each compound was of the same order of magnitude as that of momilactone B. Expression analyses of the diterpene cyclase genes responsible for the biosynthesis of momilactones and phytocassanes suggest that these phytoalexins found in roots are primarily biosynthesized in those roots. None of phytocassanes B–E exhibited allelopathic activity against dicot seedling growth, whereas momilactone A showed much weaker allelopathic activity than momilactone B. The exudation of diterpene phytoalexins from the roots might be part of a system for defense against root-infecting pathogens.  相似文献   

5.
信号传导拮抗物对大豆细胞植保素和异黄酮积累的影响   总被引:3,自引:0,他引:3  
磷酸酶的抑制剂花萼海绵诱癌素A、芫菁素和冈田酸都能诱导大豆植保素(大豆素)的积累。相反,激酶的抑制剂K252a几乎完全阻止它们诱导大豆素的合成。与磷酸酶抑制剂相比较,酵母细胞壁激发子(YE)有利于诱导黄苷元、染料木苷等异黄酮中间体的积累,而磷酸酶的抑制剂有利于大豆素的合成。YE和芫菁素还呈现出协同诱导大豆素积累的效果。通过磷脂酶A2的抑制剂与阻止线粒体ATP合酶活性的化合物的分别处理,发现茉莉酸信号传导途径是参与调控大豆植保素合成的重要途径之一,而植保素的合成需要线粒体提供能量。  相似文献   

6.
Phaseollin is metabolised by cultures of Septoria nodorum, a non-pathogen of bean, into cis and trans isomers of 12,13-dihydrodihydroxyphaseollin. These products are much less fungitoxic than phaseollin which suggests that the capacity to detoxify phytoalexins is not confined to pathogenic fungi.  相似文献   

7.
杂草给水稻(Oryza sativa)生产带来严重损失,利用水稻自身化感作用被认为是对环境友好的杂草控制方法。稻壳酮A和B是水稻抑制杂草的主要化感物质,其中稻壳酮B是至今发现最高效的天然除草剂之一,具有很好的应用潜力。稻壳酮B可以从水稻根系释放到土壤中抑制周围稗草等植物的种子萌芽和生长。稻壳酮B的浓度大于3 nmol·mL~(-1)时就能抑制水芹和莴苣的根和胚轴生长,同时稻壳酮A和B是水稻重要的植保素,可有效抑制水稻病原菌比如稻瘟病菌(Magnaporthe grisea)等。此外,稻瘟病菌感染可诱导水稻合成更多的稻壳酮。该文主要对国内外有关水稻化感物质稻壳酮的性质、分布状况、化感作用、生物合成途径、检测方法、人工合成方法和影响因素等方面的研究进行了综述。在此基础上进一步探讨稻壳酮研究过程中简捷检测方法、诱导因子和人工合成等问题。  相似文献   

8.
诱导子促进植物次生代谢产物生产的研究进展   总被引:12,自引:0,他引:12  
本文简要介绍了诱导子的分类和应用概况,讨论了诱导子的筛选、作用机制、作用效果等研究热点问题,同时简要介绍了诱导子之间的互作关系以及诱导子对植物生理生化反应的影响。  相似文献   

9.
Plants have evolved a broad array of defense mechanisms involved in disease resistance. These include synthesis of phytoalexin antibiotics and proteinase inhibitors, deposition of cell wall materials, and accumulation of hydrolytic enzymes such as chitinases. Resistance appears to depend on the ability of the host to recognize the pathogen rapidly and induce these defense responses in order to limit pathogen spread. Application of molecular technologies has yielded significant new information on mechanisms involved in pathogen recognition, signal transduction, and defense-related gene activation, and is leading to novel strategies for engineering enhanced disease resistance. We are using these approaches to analyze regulation of 3-hydroxy-3-methylglutaryl CoA reductase (HMGR), a key enzyme mediating the production of terpenoid defense compounds. This enzyme is encoded by four genes in tomato; hmg2 gene expression is specifically associated with responses to pathogen or defense elicitors. Transgenic plants containing DNA constructs that fuse the hmg2 promoter to a reporter gene have been used to analyze both tissue specificity and patterns of defense-related expression. Because this gene is rapidly induced in tissues directly surrounding the site of ingress by a variety of pathogens, it may serve as a valuable tool in engineering new disease-resistance mechanisms.  相似文献   

10.
Two metabolites of the phytoalexin phaseollin (1) produced by cultures of the fungus Colletotrichum lindemuthianum have been assigned structures (3) and (4).  相似文献   

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