In the present manuscript, we describe the mechanisms involved in the yeast-to-hypha dimorphic transition of the plant pathogenic Basidiomycota fungus Ustilago maydis. During its life cycle, U. maydis presents two stages: one in the form of haploid saprophytic yeasts that divide by budding and the other that is the product of the mating of sexually compatible yeast cells (sporidia), in the form of mycelial dikaryons that invade the plant host. The occurrence of the involved dimorphic transition is controlled by the two mating loci a and b. In addition, the dimorphic event can be obtained in vitro by different stimuli: change in the pH of the growth medium, use of different carbon sources, and by nitrogen depletion. The presence of other factors and mechanisms may affect this phenomenon; among these, we may cite the PKA and MAPK signal transduction pathways, polyamines, and factors that affect the structure of the nucleosomes. Some of these factors and conditions may affect all these dimorphic events, or they may be specific for only one or more but not all the processes involved. The conclusion reached by these experiments is that U. maydis has constituted a useful model for the analysis of the mechanisms involved in cell differentiation of fungi in general.

中文翻译：

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担子菌（Basidiomycota）真菌Ustilago maydis双态现象的信号传导机制。

在本手稿中，我们描述了植物致病性担子菌真菌Ustilago maydis从酵母到菌丝的双态转化的机制。在其生命周期中，U。maydis呈现两个阶段：一个是通过芽生分裂的单倍体腐生酵母形式，另一个是具有性相容性的酵母细胞（孢子虫）交配的产物，以菌丝体双核体的形式存在。入侵植物宿主。涉及的双态转变的发生由两个交配基因座a和b控制。此外，双态事件可以通过不同的刺激在体外获得：生长培养基的pH值变化，使用不同的碳源以及氮耗竭。其他因素和机制的存在可能会影响这种现象；其中，我们可以列举PKA和MAPK信号转导途径，多胺以及影响核小体结构的因素。这些因素和条件中的某些可能会影响所有这些二态事件，或者它们可能仅对一个或多个而不是所有涉及的过程具有特异性。通过这些实验得出的结论是，马氏假单胞菌已构成了有用的模型，用于分析通常涉及真菌细胞分化的机制。