New Insights Into the Roles of NADPH Oxidases in Sexual Development and Ascospore Germination in Sordaria macrospora
New Insights Into the Roles of NADPH Oxidases in Sexual Development and Ascospore Germination in Sordaria macrospora
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DOI：
10.1534/genetics.113.159368
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发表时间：
2014-03-01
期刊：
影响因子：
3.3
通讯作者：
Kueck, Ulrich
中科院分区：
文献类型：
--
作者：
Dirschnabel, Daniela Elisabeth;Nowrousian, Minou;Kueck, Ulrich
NADPH氧化酶(NOX)衍生的活性氧物种(ROS)是诱导不同细胞过程的信号决定因素。为了表征NOX在真菌发育过程中的功能，我们利用了遗传上易驯化的子囊菌大孢子菌。对一个不育突变体的基因组测序使我们确定编码nox1的NADPH氧化酶是子实体形成、菌丝正常生长和菌丝融合所必需的基因。这些表型与Nor1相同，缺少NOX调节因子Nor1。进一步的表型分析表明，nox1和其他不育突变体中ROS产量的增加与菌丝融合缺陷之间存在高度的相关性。对野生型和nox1菌丝体和分离的原皮进行的全基因组转录图谱分析表明，nox1失活影响了与细胞骨架重塑、菌丝融合、代谢和线粒体呼吸相关的基因的表达。缺失NADPH氧化酶2基因Nor1的NOX2和转录因子缺失突变体STE12的遗传分析表明，NOX2的子囊孢子萌发存在严格的黑色素依赖缺陷，表明这三个基因具有共同的遗传途径。我们报道了编码G蛋白亚基的gsa3和编码cAMP产生的腺苷环化酶的SAc1在萌发过程中以不同的途径发挥作用。CAMP以一种黑色素依赖的方式抑制子囊孢子萌发的发现支持了cAMP抑制NOX2活性的模型，从而表明这两条途径之间存在联系。我们的结果扩展了目前关于NOX酶在真菌发育中的作用的知识，并提供了一个框架来定义真菌中NOX信号通路的上游和下游组成部分。
NADPH oxidase (NOX)-derived reactive oxygen species (ROS) act as signaling determinants that induce different cellular processes. To characterize NOX function during fungal development, we utilized the genetically tractable ascomycete Sordaria macrospora. Genome sequencing of a sterile mutant led us to identify the NADPH oxidase encoding nox1 as a gene required for fruiting body formation, regular hyphal growth, and hyphal fusion. These phenotypes are shared by nor1, lacking the NOX regulator NOR1. Further phenotypic analyses revealed a high correlation between increased ROS production and hyphal fusion deficiencies in nox1 and other sterile mutants. A genome-wide transcriptional profiling analysis of mycelia and isolated protoperithecia from wild type and nox1 revealed that nox1 inactivation affects the expression of genes related to cytoskeleton remodeling, hyphal fusion, metabolism, and mitochondrial respiration. Genetic analysis of nox2, lacking the NADPH oxidase 2 gene, nor1, and transcription factor deletion mutant ste12, revealed a strict melanin-dependent ascospore germination defect, indicating a common genetic pathway for these three genes. We report that gsa3, encoding a G-protein -subunit, and sac1, encoding cAMP-generating adenylate cyclase, act in a separate pathway during the germination process. The finding that cAMP inhibits ascospore germination in a melanin-dependent manner supports a model in which cAMP inhibits NOX2 activity, thus suggesting a link between both pathways. Our results expand the current knowledge on the role of NOX enzymes in fungal development and provide a frame to define upstream and downstream components of the NOX signaling pathways in fungi.