Pheromones are essential for male fertility and sufficient to direct chemotropic polarized growth of trichogynes during mating in Neurospora crassa
Pheromones are essential for male fertility and sufficient to direct chemotropic polarized growth of trichogynes during mating in Neurospora crassa
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DOI：
10.1128/ec.5.3.544-554.2006
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发表时间：
2006-03-01
期刊：
影响因子：
--
通讯作者：
Borkovich, KA
中科院分区：
文献类型：
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作者：
Kim, H;Borkovich, KA
草神经孢子虫是一种自不育的丝状真菌，有两种交配类型：毡a和毡a。其交配过程涉及到雌性特异性菌丝（trichogynes）向相反交配类型的雄性细胞的趋化极化生长，这一过程涉及信息素和受体。mat A细胞表达ccg-4信息素和pre-1受体，mat A细胞表达mfa-1信息素和pre-2受体的mRNA；MFA-1和CCG-4分别是PRE-1和PRE-2的预测配体。在这项研究中，我们产生了Delta ccg-4和Delta mfa-1突变体，并设计了一个mat a菌株来共表达ccg-4及其受体pre-2。作为雄性突变体，Delta ccg-4 matA和Delta mfa-1 matA分别不能吸引matA和matA旋丝虫，因此不能启动子体（周周）发育或产生减数分裂孢子（子囊孢子）。相比之下，Delta ccg-4 mat a和Delta mfa-1 mat a突变体表现出正常的趋化性吸引和雄性生育能力。Delta ccg-4 - Delta mfa-1双突变体在两种交配类型中均表现出趋化性缺陷和雄性不育。ccg-4的异源表达使雄性mata能够吸引mata tricogynes，尽管随后的周周分化没有发生。ccg-4和pre-2在同一菌株中的表达引发自激，形成无子囊孢子的贫瘠包皮。我们的研究结果表明，CCG-4和MFA-1是交配型特异性雄性生殖所必需的，信息素（和受体）是配偶识别过程中性别身份的初始决定因素。此外，自我吸引信号可以在表达信息素及其同源受体的菌株内传递。
Neurospora crassa is a self-sterile filamentous fungus with two mating types, mat A and mat a. Its mating involves chemotropic polarized growth of female-specific hyphae (trichogynes) toward male cells of the opposite mating type in a process involving pheromones and receptors. mat A cells express the ccg-4 pheromone and the pre-1 receptor, while mat a strains produce mRNA for the pheromone mfa-1 and the pre-2 receptor; MFA-1 and CCG-4 are the predicted ligands for PRE-1 and PRE-2, respectively. In this study, we generated Delta ccg-4 and Delta mfa-1 mutants and engineered a mat a strain to coexpress ccg-4 and its receptor, pre-2. As males, Delta ccg-4 mat A and Delta mfa-1 mat a mutants were unable to attract mat a and matA trichogynes, respectively, and consequently failed to initiate fruiting body (perithecial) development or produce meiotic spores (ascospores). In contrast, Delta ccg-4 mat a and Delta mfa-1 mat A mutants exhibited normal chemotropic attraction and male fertility. Delta ccg-4 Delta mfa-1 double mutants displayed defective chemotropism and male sterility in both mating types. Heterologous expression of ccg-4 enabled mat a males to attract mat a trichogynes, although subsequent perithecial differentiation did not occur. Expression of ccg-4 and pre-2 in the same strain triggered self-stimulation, resulting in formation of barren perithecia with no ascospores. Our results indicate that CCG-4 and MFA-1 are required for mating-type-specific male fertility and that pheromones (and receptors) are initial determinants for sexual identity during mate recognition. Furthermore, a self-attraction signal can be transmitted within a strain that expresses a pheromone and its cognate receptor.