Determinants of Mating Type in Phytophthora

疫霉属交配类型的决定因素

• 批准号: 9722947
• 负责人: Howard Judelson
• 金额: $ 31.5万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-02-01 至 2002-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9722947&HistoricalAwards=false
• 关键词: Determinants; Mating; Type; Phytophthora

Judelson 9722947 The goal of this research is to understand the regulation and evolution of mating systems in oomycete fungi. Using the heterothallic species Phytophthora infestans as a model system, the basis of mating type (sexual compatibility) will be determined by cloning the mating type locus and determining its function. This is expected to lead to studies of other heterothallic and homothallic species of Phytophthora, of mating type loci in other oomyceteous genera, and of other genes involved in the mating response. During previous studies by this laboratory DNA markers flanking the mating type locus were isolated and used to develop a genetic model to explain the determination of mating type; those markers are now being used to isolate the mating type locus by chromosome walking using cosmid and bacterial artificial chromosome libraries. In addition, the prior studies indicated that the chromosomal region containing the mating type determinants of P. infestans displayed several unusual genetic and physical characteristics. These included a non-Mendelian pattern of inheritance equivalent to that observed in systems of balanced lethal loci, and instability of the region as evidenced by its propensity to rearrange; these phenomena will continue to be addressed in this project. The oomycetes are an important but under-studied group of diploid lower eukaryotes that include many economically and environmentally significant species. These include pathogens of plants and animals, biocontrol agents of other pathogens, and saprophytes. P. infestans is a natural first choice for these studies due to the well-developed molecular and classical genetic techniques available for the species. P. infestans is also a widespread and enormously important pathogen of several food crops. Consequently, the importance of developing expertise in the molecular manipulation of this pathogen can not be over-stressed. Furthermore, the analysis of mating type in P. infestans represents an opportunity to study an important aspect of its biology. Mating systems are significant since they regulate the flow of genes through populations; for plant pathogens such as P. infestans, such genes include those determining pathogenicity, host preference, race specificity, and fungicide resistance. The mating cycle is also significant since the sexual spores (oospores) are long-lived and serve as an important source of inoculum for outbreaks of plant disease. Much will be learned from these studies including information about the regulation of mating type in diploids and the evolution of an unusual chromosomal region. This research will also illuminate fundamental aspects of oomycete biology, including those concerning gene regulation, cellular communication, signal transduction, and development. It is likely that mating in oomycetes is regulated by mechanisms very different from those of ascomycetes and basidiomycetes, which lack taxonomic affinity to the oomycetes and in which mating is controlled by different genetic and biochemical mechanisms. In the long term, these studies may have significant practical applications as well. If the factors which control mating can be identified, it might be possible to control plant diseases by manipulating or exploiting portions of the mating cycle. Studies in P. infestans will naturally lead to an understanding and ultimately control of other oomycete plant pathogens as well.

Judelson 9722947本研究的目的是了解卵菌真菌交配系统的调控和进化。使用异宗配合物种致病疫霉作为模型系统，将通过克隆交配型基因座并确定其功能来确定交配型的基础（性相容性）。这有望导致其他异宗配合和同宗配合的疫霉属物种的研究，在其他卵菌属的交配型位点，以及其他基因参与交配反应。 在本实验室以前的研究中，分离出交配型基因座侧翼的DNA标记，并用于开发遗传模型来解释交配型的确定;这些标记现在被用于通过使用粘粒和细菌人工染色体文库的染色体步移来分离交配型基因座。此外，以往的研究表明，含有交配型决定因子的致病疫霉染色体区域显示出一些不寻常的遗传和物理特性。这些包括一个非孟德尔模式的继承相当于在系统中观察到的平衡致死基因座，和不稳定的地区证明了其倾向重新排列，这些现象将继续在这个项目中得到解决。 卵菌是一类重要的二倍体低等真核生物，包括许多具有经济和环境意义的物种。这些包括植物和动物的病原体、其他病原体的生物控制剂和腐殖酸。致病疫霉是这些研究的自然首选，由于发达的分子和经典的遗传技术可用于该物种。 致病疫霉也是几种粮食作物的广泛和非常重要的病原体。因此，发展这种病原体的分子操纵方面的专门知识的重要性怎么强调都不过分。此外，对致病疫霉交配型的分析为研究其生物学的一个重要方面提供了机会。交配系统是重要的，因为它们调节基因在种群中的流动;对于植物病原体如致病疫霉，这些基因包括决定致病性、宿主偏好、种族特异性和杀真菌剂抗性的基因。交配周期也很重要，因为有性孢子（卵孢子）寿命长，是植物病害爆发的重要接种源。 从这些研究中可以学到很多东西，包括二倍体交配型的调节和一个不寻常的染色体区域的进化。这项研究也将阐明卵菌生物学的基本方面，包括那些有关基因调控，细胞通讯，信号转导和发展。很可能卵菌中的交配是由与子囊菌和担子菌非常不同的机制调节的，子囊菌和担子菌与卵菌缺乏分类学上的亲和力，并且其中交配是由不同的遗传和生化机制控制的。从长远来看，这些研究也可能具有重要的实际应用价值。如果控制交配的因素能够被识别出来，就有可能通过操纵或利用交配周期的一部分来控制植物疾病。对致病疫霉的研究自然也会导致对其他卵菌植物病原体的了解和最终控制。