Involvement of FgERG4 in ergosterol biosynthesis, vegetative differentiation and virulence in Fusarium graminearum
Involvement of FgERG4 in ergosterol biosynthesis, vegetative differentiation and virulence in Fusarium graminearum
复制标题
FgERG4 参与禾谷镰刀菌麦角甾醇生物合成、营养分化和毒力
DOI：
10.1111/j.1364-3703.2012.00829.x
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发表时间：
2013-01-01
影响因子：
4.9
通讯作者：
Ma, Zhonghua
中科院分区：
文献类型：
--
作者：
Liu, Xin;Jiang, Jinhua;Ma, Zhonghua
麦角固醇的生物合成途径在酿酒酵母中已被充分了解，但目前对植物病原真菌中的途径知之甚少。在这项研究中，我们的特点是禾谷镰刀菌FgERG 4基因编码甾醇C-24还原酶，催化麦角甾-5，7，22，24-四烯醇转化为麦角甾醇的麦角甾醇生物合成的最后一步。FgERG 4缺失突变体？FgErg 4 - 2不能合成麦角甾醇。该突变体的菌丝生长和产孢能力显著下降，产生畸形分生孢子。此外，突变体表现出增加的敏感性，金属阳离子和各种细胞应力。令人惊讶的是，菌丝体？FgErg4 - 2显示对细胞壁降解酶的抗性增加。杀菌剂敏感性测试显示？FgErg 4 - 2对多种甾醇生物合成抑制剂（SBI）的抗性增强，这与突变体中SBI靶基因的过表达一致。? FgErg 4 - 2的毒力显著受损，尽管它能够成功地定殖开花小麦穗和番茄，这与突变体产生比野生型祖细胞显著更低水平的异青霉烯真菌毒素的观察结果一致。所有这些表型缺陷？通过重新引入全长FgERG 4基因来补充FgERG 4 - 2。此外，FgERG 4部分挽救了酿酒酵母ERG 4缺失突变体中麦角固醇生物合成的缺陷。综上所述，本研究的结果表明，FgERG 4在麦角甾醇生物合成，营养分化和丝状真菌F.？禾谷早熟禾
The ergosterol biosynthesis pathway is well understood in Saccharomyces cerevisiae, but currently little is known about the pathway in plant-pathogenic fungi. In this study, we characterized the Fusarium graminearum FgERG4 gene encoding sterol C-24 reductase, which catalyses the conversion of ergosta-5,7,22,24-tetraenol to ergosterol in the final step of ergosterol biosynthesis. The FgERG4 deletion mutant ?FgErg4-2 failed to synthesize ergosterol. The mutant exhibited a significant decrease in mycelial growth and conidiation, and produced abnormal conidia. In addition, the mutant showed increased sensitivity to metal cations and to various cell stresses. Surprisingly, mycelia of ?FgErg4-2 revealed increased resistance to cell wall-degrading enzymes. Fungicide sensitivity tests revealed that ?FgErg4-2 showed increased resistance to various sterol biosynthesis inhibitors (SBIs), which is consistent with the over-expression of SBI target genes in the mutant. ?FgErg4-2 was impaired dramatically in virulence, although it was able to successfully colonize flowering wheat head and tomato, which is in agreement with the observation that the mutant produces a significantly lower level of trichothecene mycotoxins than does the wild-type progenitor. All of these phenotypic defects of ?FgErg4-2 were complemented by the reintroduction of a full-length FgERG4 gene. In addition, FgERG4 partially rescued the defect of ergosterol biosynthesis in the Saccharomyces cerevisiae ERG4 deletion mutant. Taken together, the results of this study indicate that FgERG4 plays a crucial role in ergosterol biosynthesis, vegetative differentiation and virulence in the filamentous fungus F.?graminearum.