Functional roles of FgLaeA in controlling secondary metabolism, sexual development, and virulence in Fusarium graminearum.
Functional roles of FgLaeA in controlling secondary metabolism, sexual development, and virulence in Fusarium graminearum.
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DOI：
10.1371/journal.pone.0068441
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Yun SH
中科院分区：
文献类型：
--
作者：
Kim HK;Lee S;Jo SM;McCormick SP;Butchko RA;Proctor RH;Yun SH
禾谷镰刀菌 (Fusarium graminearum) 是谷类作物中镰刀菌赤霉病的病原体，它在受感染的植物中产生霉菌毒素，例如单端孢霉烯族化合物和玉米赤霉烯酮。在这里，我们重点研究了禾谷镰刀菌中 FgLaeA 的功能，FgLaeA 是构巢曲霉 LaeA 的同源物，编码次级代谢和性发育的全局调节因子。在基因分析之前，我们构建了一个新的荧光素酶报告系统，该系统由转基因禾谷镰刀菌菌株组成，该菌株在控制这些霉菌毒素生物合成的 TRI6 或 ZEB2 启动子的控制下表达萤火虫荧光素酶基因。 FgLaeA 的靶向删除导致报告菌株的发光急剧减少，表明 FgLaeA 控制着禾谷镰刀菌中这些转录因子的表达； GC-MS 分析进一步证实了毒素积累的减少。 FgLaeA 的过度表达导致单端孢霉烯族化合物和其他代谢物的产生增加。 RNA seq 分析显示，之前提出的占总暂定基因簇约 70% 的基因成员在 ΔFgLaeA 菌株中差异表达。此外，ΔFgLaeA菌株表现出较早诱导有性子实体（子囊壳）形成，并显着减少小麦中的疾病症状，表明FgLaeA似乎负向控制子囊壳诱导，但正向控制对宿主植物的毒力。 FgLaeA 在霉菌毒素产生和性发育条件下均持续表达。 ΔFgLaeA 菌株中 GFP-FgLaeA 融合构建体的过表达将所有表型变化恢复至野生型水平，并导致 GFP 在不同发育阶段的细胞核和细胞质中组成型表达。裂解荧光素酶测定表明 FgLaeA 能够与构巢曲霉 veA 的同源物 FgVeA 相互作用。综上所述，这些结果表明，FgLaeA（假定的 FgVeA 复合体的成员）控制着禾谷镰刀菌的次生代谢、性发育和毒力，尽管其具体调节模式与构巢曲霉中的 LaeA 不同。
Fusarium graminearum, the causal agent of Fusarium head blight in cereal crops, produces mycotoxins such as trichothecenes and zearalenone in infected plants. Here, we focused on the function of FgLaeA in F. graminearum, a homolog of Aspergillus nidulans LaeA encoding the global regulator for both secondary metabolism and sexual development. Prior to gene analysis, we constructed a novel luciferase reporter system consisting of a transgenic F. graminearum strain expressing a firefly luciferase gene under control of the promoter for either TRI6 or ZEB2 controlling the biosynthesis of these mycotoxins. Targeted deletion of FgLaeA led to a dramatic reduction of luminescence in reporter strains, indicating that FgLaeA controls the expression of these transcription factors in F. graminearum; reduced toxin accumulation was further confirmed by GC-MS analysis. Overexpression of FgLaeA caused the increased production of trichothecenes and additional metabolites. RNA seq-analysis revealed that gene member(s) belonging to ∼70% of total tentative gene clusters, which were previously proposed, were differentially expressed in the ΔFgLaeA strain. In addition, ΔFgLaeA strains exhibited an earlier induction of sexual fruiting body (perithecia) formation and drastically reduced disease symptoms in wheat, indicating that FgLaeA seems to negatively control perithecial induction, but positively control virulence toward the host plant. FgLaeA was constitutively expressed under both mycotoxin production and sexual development conditions. Overexpression of a GFP-FgLaeA fusion construct in the ΔFgLaeA strain restored all phenotypic changes to wild-type levels and led to constitutive expression of GFP in both nuclei and cytoplasm at different developmental stages. A split luciferase assay demonstrated that FgLaeA was able to interact with FgVeA, a homolog of A. nidulans veA. Taken together, these results demonstrate that FgLaeA, a member of putative FgVeA complex, controls secondary metabolism, sexual development, and virulence in F. graminearum, although the specific regulation pattern differs from that of LaeA in A. nidulans.
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影响因子：
3
作者：
Butchko, Robert A. E.;Brown, Daren W.;Wiemann, Philipp
通讯作者：
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