C3 unit addition reaction accompanied by formation of C-C bond in phytotoxin biosynthesis of phytopathogen.

植物病原体的植物毒素生物合成中伴随C-C键形成的C3单元加成反应。

• 批准号: 09660118
• 负责人: NAKAJIMA Hiromitsu
• 金额: $ 2.11万
• 依托单位: Tottori University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09660118/
• 关键词: plant pathogens; phytotoxins; biosynthesis; Bipolaris sorokiniana; sesquiterpene; L- [hydroxy-^<18>O] malic acid; sorokinianin

Sorokinianin is a phytotoxin produced by a strain (OB-25-l) of Bipolaris sorokiniana, a pathogen causing spot blotch or foot and root rot diseases of wheat and other grasses. This toxin is assumed to be composed of a helminthosporol-type sesquiterpene and a C_3 portion. To clarify the biosynthetic origin we conducted three experiments : a [1,2-^<13>C_2] sodium acetate feeding experiment ; a replacement culture experiment with the candidates for the C_3 unit precursor, together with prehelminthosporol, the major metabolite of the strain OB-25-1 ; and a [2,3-^<13>C_2] succinic acid feeding experiment. The results of these experiments suggested that sorokinianin was synthesized from prehelminthosporol by reactions that include the addition of a member of the TCA cycle, decarboxylation and lactonization. To determine the direct C_3 unit precursor we prepared L-[hydroxy-^<18>O] malic acid from fumaric acid by fumarase and H_2_<18>O and conducted a L-[hydroxy-^<18>O] malic acid feeding experiment. The results of the experiment indicated that the direct C_3 unit precursor was not malic acid/oxalacetic acid but fumaric acid/succinic acid.

索洛基亚菌素是由引起小麦和其他牧草斑点病或足腐病和根腐病的一种病原菌--索洛克尼亚双极菌(Bipolaris Sorokiniana)(OB-25-L)产生的一种植物毒素。推测该毒素由蠕孢子醇型倍半萜和C_3部分组成。为了阐明菌株的生物合成来源，我们进行了三个实验：[1，2-^&lt；13&gt；C_2]醋酸钠补料实验，C_3单元前体与菌株OB-25-1的主要代谢产物前蠕孢子醇的置换培养实验，以及[2，3-^&t；13&gt；C_2]琥珀酸补料实验。这些实验结果表明，前蠕虫孢子酚是通过TCA环加成、脱羧化和内酯化等反应合成索洛基尼亚素的。为了确定直接的C_3单元前体，我们以富马酸为原料，通过富马酸酶和H_2_(18&gt；O)反应制备了L-[羟基]苹果酸，并进行了L-[羟基]苹果酸的加料实验。实验结果表明，C3单元的直接前驱体不是苹果酸/草酸，而是富马酸/丁二酸。

项目成果

H.Nakajima: "Cochliospicin A:a new metabolite related to spiciferinone,a phytotoxin of the fungus Cochliobolus spicifer" Journal of Natural Products. 60. 414-416 (1997)

H.Nakajima：“Cochliospicin A：一种与 spiciferinone 相关的新代谢物，一种真菌 Cochliobolus spicifer 的植物毒素”《天然产物杂志》。

中島廣光 (分担執筆): "植物病害の化学" 市原耿民・上野民夫編 学会出版センター, 290 (1997)

中岛宏光（撰稿人）：《植物病害化学》，市原小民和上野民夫编辑，学会出版中心，290（1997）

H.Nakajima: "Cochliospicin A : a new metabolite related to spiciferinoe, a phytotoxin of the fungus Cochliobolus spicifer" J.Nat.Prod.60. 414-416 (1997)

H.Nakajima：“Cochliospicin A：一种与 spiciferinoe 相关的新代谢物，spiciferinoe 是真菌 Cochliobolus spicifer 的植物毒素”J.Nat.Prod.60。

H.Nakajima: "Structures and biosyntheses of phytotoxins in Cochliobolus spicifer and Bipolaris sorokiniana : C_3 unit addition reaction in phytotoxin biosyntheses." K.Kohmoto and O.C.Yoder (eds.) Molecular Genetics of Host-Specific Toxins in Plant Disease

H.Nakajima：“Cochliobolus spicifer 和 Bipolaris sorokiniana 中植物毒素的结构和生物合成：植物毒素生物合成中的 C_3 单元加成反应。”

H.Nakajima(分担執筆): "Molecular Genetics of Host-Specific Toxins in Plant Disease" Edited by K.Kohmoto and O.C.Yoder Kluwer Academic Publishers, 413 (1998)

H. Nakajima（贡献者）：“植物病害宿主特异性毒素的分子遗传学”，K.Kohmoto 和 O.C.Yoder Kluwer 学术出版社编辑，413 (1998)