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Elicitors and phytotoxins from the blackleg fungus: Structure, bioactivity and biosynthesis.

机译：黑腿真菌的引发剂和植物毒素：结构，生物活性和生物合成。

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摘要

The phytopathogenic fungus Leptosphaeria maculans can cause blackleg disease on crucifers, which results in significant yield losses. Fungal diseases involve interactions between pathogenic fungi and host plants. One aspect of these interactions is mediated by secondary metabolites produced by both fungi and host plants. Phytotoxins and elicitors as well as phytoanticipins and phytoalexins are metabolites produced by fungi and plants, respectively. This thesis describes and discusses the isolation, structure, biological activity and biosynthesis of the secondary metabolites produced by L. maculans .;New metabolites maculansins A (299) and B (300), which were not detected in cultures of L. maculans incubated in MM, were isolated from cultures of L. maculans incubated in potato dextrose broth (PDB). Maculansins A (299) and B ( 300) displayed higher phytotoxicity on brown mustard than on canola and white mustard (Sinapis alba cv. Ochre) but did not elicit detectable production of phytoalexins in either brown mustard or canola. Metabolite 2,4-dihydroxy-3,6-dimethylbenzaldehyde (212) was produced in higher amount in cultures of L. maculans incubated in PDB than in MM and displayed strong inhibition effect on the root growth of brown mustard and canola.;L. maculans incubated in MM amended with high concentration of NaCl produced a new metabolite, 8-hydroxynaphthalene-1-sulfate ( 293), and a known metabolite, bulgarein (294), which are likely involved in the self-protection.;The potential intermediates involved in the biosynthesis of sirodesmin PL (165) were investigated using deuterium labeled precursors: [3,3-2H2]-L-tyrosine (251a), [3,3- 2H2]O-prenyl-L-tyrosine (312a), E-[3,3,5',5',5'-2H5] O-prenyl-L-tyrosine (312b), [5,5-2H 2]phomamide (171a), [2,3,3-2H3]-L-serine (233d) and [5,5-2H2]cyclo-L-tyr-L-ser (252a). Intact incorporation of [5,5-2H2 ]phomamide (171a) into sirodesmin PL (165) suggested that leptomaculin D (272) and E (274), and deacetylleptomaculin D (273) and E (275) are not intermediates in the biosynthesis of sirodesmin PL (165). They are more likely the catabolic metabolites of sirodesmin PL (165 ). Phomamide (171), the intermediate in the biosynthetic pathway of sirodesmin PL (165), is likely biosynthesized by coupling of prenyl tyrosine (312) with serine (233) rather than prenylation of cyclo-L-tyr-L-ser (252). When [3,3- 2H2]-L-tyrosine (251a), [3,3-2H 2]O-prenyl-L-tyrosine (312a), and E-[3,3,5',5',5'-2H5] O-prenyl-L-tyrosine (312b) were fed into cultures of L. maculans, a beta proton exchange was detected by 1H NMR through intrinsic steric isotope effect, which occurs before the formation of phomamide (171). The biosynthesis and catabolism of sirodesmin PL (165) were proposed based on the results obtained in this work.;The elicitor-toxin activity bioassay guided isolation of elicitors and phytotoxins produced by L. maculans in a chemically defined medium lead to the isolation of general elicitors, sirodesmin PL (165 ) and deacetylsirodesmin PL (166), and specific elicitors, cerebrosides C (14) and D (31) from minimum medium (MM) culture under standard conditions. The known phytotoxins sirodesmin PL (165) and deacetylsirodesmin PL (166) induced the production of phytoalexin spirobrassinin (122) in both resistant plant species (brown mustard, Brassica juncea cv. Cutlass) and susceptible plant species (canola, B. napus cv. Westar). A mixture of cerebrosides C (14) and D (31) induced the production of the phytoalexin rutalexin (127) in resistant plant species (brown mustard, B. juncea cv. Cutlass) but not in susceptible plant species (canola, B. napus cv. Westar). New metabolites leptomaculins A-E (267-269, 272 and 274) and deacetylleptomaculins C-E (270, 273 and 275) were isolated from elicitor-phytotoxin active fractions but did not display detectable elicitor activity or phytotoxicity after purification.
机译：植物致病性真菌黄腐乳杆菌可在十字花科植物上引起黑腿病，导致产量大幅下降。真菌病涉及病原真菌和宿主植物之间的相互作用。这些相互作用的一方面是由真菌和宿主植物产生的次生代谢产物介导的。植物毒素和引发剂以及植物抗毒素和植物抗毒素分别是真菌和植物产生的代谢产物。本文描述和讨论了由黄斑狼疮产生的次级代谢产物的分离，结构，生物学活性和生物合成。新的代谢产物黄斑狼毒素A（299）和B（300），在培养的黄斑狼疮细菌培养物中未检出。从马铃薯右旋糖肉汤（PDB）中培养的黄斑狼疮菌的培养物中分离出MM。 Maculansins A（299）和B（300）在芥菜上显示出比双低油菜籽和白芥菜（Sinapis alba cv。Ochre）更高的植物毒性，但在芥菜或双低油菜中均未产生可检测到的植物抗毒素。在PDB中培养的黄斑狼疮培养物中产生的代谢物2,4-二羟基-3,6-二甲基苯甲醛（212）的生成量高于MM，并且对棕芥子和低芥酸菜子的根部生长表现出强烈的抑制作用。在高浓度NaCl修饰的MM中孵育的黄斑产生了新的代谢物8-羟基萘-1-硫酸盐（293）和已知的代谢物bulgarein（294），它们可能参与自我保护。使用氘标记的前体研究了参与西罗德明PL（165）生物合成的物质：[3,3-2H2] -L-酪氨酸（251a），[3,3- 2H2] O-异戊烯基-L-酪氨酸（312a）， E- [3,3,5'，5'，5'-2H5] O-异戊烯基-L-酪氨酸（312b），[5,5-2H 2]膦酰胺（171a），[2,3,3-2H3 ] -L-丝氨酸（233d）和[5，5-2H2]环-L-酪氨酸-L-ser（252a）。将[5,5-2H2]磷酰胺（171a）完整掺入到西罗定胺PL（165）中，表明瘦蛋白素D（272）和E（274）以及脱乙酰基瘦素D（273）和E（275）不是生物合成的中间体sirodesmin PL（165）。它们更可能是西洛德明PL（165）的分解代谢产物。磺胺（171）是Sirodesmin PL（165）生物合成途径中的中间体，很可能是通过异戊二烯基酪氨酸（312）与丝氨酸（233）偶联而不是环-L-酪氨酸-L-ser（252）的异戊酸酯化来生物合成的。当[3,3- 2H2] -L-酪氨酸（251a），[3,3-2H 2] O-异戊烯基-L-酪氨酸（312a）和E- [3,3,5'，5'，5将'-2H5] O-异戊烯基-L-酪氨酸（312b）喂入斑斑乳酸杆菌培养物中，通过1H NMR通过固有的空间同位素效应检测到β质子交换，这发生在形成酰胺之前（171）。基于这项工作获得的结果，提出了西罗德明PL（165）的生物合成和分解代谢。激发子-毒素活性生物测定法指导在化学成分确定的培养基中分离由黄斑狼疮产生的激发子和植物毒素，从而分离出一般的诱导剂，西罗德明PL（165）和去乙酰基西德明PL（166），以及特定引发剂，来自标准条件下最低培养基（MM）培养物中的脑苷C（14）和D（31）。已知的植物毒素西罗德明PL（165）和去乙酰基西德明PL（166）诱导了抗性植物物种（芥菜，芥菜品种Cutlass）和易感植物物种（canola，B. napus cv。 Westar）。脑苷C（14）和D（31）的混合物在抗性植物物种（芥菜，芥菜种c。Cutlass）中诱导了植物抗毒素rutalexin（127）的产生，但在易感植物物种（油菜，油菜中没有） cv。Westar）。从激发剂-植物毒素的活性级分中分离出新的代谢产物瘦素蛋白A-E（267-269、272和274）和脱乙酰基瘦素蛋白C-E（270、273和275），但纯化后未显示出可检测到的激发剂活性或植物毒性。

著录项

  • 作者

    Yu, Yang.;

  • 作者单位

    The University of Saskatchewan (Canada).;

  • 授予单位 The University of Saskatchewan (Canada).;
  • 学科 Agriculture Plant Pathology.;Chemistry Organic.;Chemistry Agricultural.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 232 p.
  • 总页数 232
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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