Characterization of the fusaric acid gene cluster in Fusarium fujikuroi
Characterization of the fusaric acid gene cluster in Fusarium fujikuroi
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DOI：
10.1007/s00253-013-5453-1
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发表时间：
2014-02-01
影响因子：
5
通讯作者：
Tudzynski, Bettina
中科院分区：
文献类型：
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作者：
Niehaus, Eva-Maria;von Bargen, Katharina W.;Tudzynski, Bettina
“恶苗病”真菌Fusarium fujikuroi是水稻的常见病原体，并产生多种真菌毒素、色素和植物激素。镰刀菌酸是已知最古老的由镰刀菌产生的次级代谢产物之一。fujikuroi和一些其他镰刀菌属物种。由于其存在于谷类食品和饲料中，因此对其生物合成和调控的研究具有重要意义。本研究描述了镰刀菌酸基因簇的鉴定和特征。fujikuroi由PKS编码核心基因和四个共调节基因FUB 1-FUB 5组成。除镰刀菌酸外，F. Fujikuroi产生两种镰刀菌酸样衍生物：镰刀菌醇酸和9，10-脱氢镰刀菌酸。我们提供的证据表明，这些衍生物不是镰刀菌酸生物合成途径的中间体，它们的形成是由镰刀菌酸基因簇外的基因催化的。所有五个簇基因的靶基因缺失揭示，并非所有这些都参与镰刀菌酸的生物合成。我们认为，只有两个基因，FUB 1和FUB 4，是必要的生物合成。在高氮条件下有利于FUB基因的表达和镰刀菌酸及其两种衍生物的产生。我们发现，氮依赖的表达fusaric酸基因正调控的氮响应加塔转录因子AreB，和pH值依赖的调节介导的转录因子PacC。此外，镰刀菌酸的产生受真菌特异性天鹅绒复合物的两个成员调节：Vel 1和Lae 1。在植物中的表达研究表明，与玉米相比，在最喜欢的宿主植物水稻中的表达更高。
The "bakanae" fungus Fusarium fujikuroi is a common pathogen of rice and produces a variety of mycotoxins, pigments, and phytohormones. Fusaric acid is one of the oldest known secondary metabolites produced by F. fujikuroi and some other Fusarium species. Investigation of its biosynthesis and regulation is of great interest due to its occurrence in cereal-based food and feed. This study describes the identification and characterization of the fusaric acid gene cluster in F. fujikuroi consisting of the PKS-encoding core gene and four co-regulated genes, FUB1-FUB5. Besides fusaric acid, F. fujikuroi produces two fusaric acid-like derivatives: fusarinolic acid and 9,10-dehydrofusaric acid. We provide evidence that these derivatives are not intermediates of the fusaric acid biosynthetic pathway, and that their formation is catalyzed by genes outside of the fusaric acid gene cluster. Target gene deletions of all five cluster genes revealed that not all of them are involved in fusaric acid biosynthesis. We suggest that only two genes, FUB1 and FUB4, are necessary for the biosynthesis. Expression of the FUB genes and production of fusaric acid and the two derivatives are favored under high nitrogen. We show that nitrogen-dependent expression of fusaric acid genes is positively regulated by the nitrogen-responsive GATA transcription factor AreB, and that pH-dependent regulation is mediated by the transcription factor PacC. In addition, fusaric acid production is regulated by two members of the fungal-specific velvet complex: Vel1 and Lae1. In planta expression studies show a higher expression in the favorite host plant rice compared to maize.