Species Concepts and Phylogeny in a Genus of Fungal Plant Pathogens, Ceratocystis

真菌植物病原体 Ceratocystis 属的物种概念和系统发育

• 批准号: 9870675
• 负责人: Thomas Harrington
• 金额: $ 21.13万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9870675&HistoricalAwards=false
• 关键词: Species; Concepts; Phylogeny; Genus; Fungal

Harrington DEB9870675 Recognition of fungal species and a better understanding of their evolution are needed. For example humans move plant pathogenic fungi around the world on their crops and plant products, often with devastating consequences. Introductions of new pathogens and changes in fungal populations frequently frustrate disease control strategies, reduce food and fiber productivity, and threaten forest ecosystems. In fact human dispersal even may be greatly accelerating the rate of evolution of many plant pathogens. Ceratocystis species, which are primarily found in the Americas, have been particularly damaging when introduced into new ecosystems or when introduced plant hosts come into contact with indigenous pathogen populations. The limited morphological variation within Ceratocystis may reflect constraints associated with dependency on non-specific insects for dissemination, and physiological adaptation to new hosts may have been the driving force in speciation of these fungi. Dr. Harrington, a recognized expert on the group will delimit species within the genus using a broader array of criteria than traditionally has been used: morphology, interfertility tests, physiology, and phylogenetic analyses of DNA sequences of ribosomal and mating type genes. Nuclear and mitochondrial DNA fingerprinting will be used to identify genetic diversity of populations and distinguish indigenous populations (high diversity) from introduced populations (limited diversity due to genetic bottlenecks). In addition Ceratocystis has many different reproductive strategies, perhaps the most complex array identified in a fungal group, and work on the molecular basis of the mating systems will continue. Evolution of mating systems and host specialization will be traced through the phylogenetic schemes developed through DNA sequence analysis. These works will build a foundation for systematic treatment of this ecologically important genus and allow for a more practical definition of species in t he fungi.

哈灵顿DEB9870675承认真菌物种并更好地了解它们的进化是必要的。例如，人类将植物病原真菌转移到世界各地的农作物和植物产品上，往往会造成毁灭性的后果。新病原体的引入和真菌种群的变化经常使疾病控制战略受挫，降低食物和纤维生产率，并威胁森林生态系统。事实上，人类的扩散甚至可能大大加快了许多植物病原体的进化速度。主要在美洲发现的Ceratcystis物种，在被引入新的生态系统或当被引入的植物宿主与当地病原体种群接触时，具有特别的破坏性。Ceratcystis内有限的形态变异可能反映了与依赖非特定昆虫传播相关的限制，而对新宿主的生理适应可能是这些真菌物种形成的驱动力。哈林顿博士是该组织公认的专家，他将使用比传统使用的更广泛的一系列标准来界定该属内的物种：形态、干扰测试、生理学以及核糖体和交配型基因的DNA序列的系统发育分析。核DNA指纹和线粒体DNA指纹将被用来确定种群的遗传多样性，并区分土著种群(高多样性)和引进种群(由于遗传瓶颈导致的有限多样性)。此外，Ceratcystis有许多不同的繁殖策略，可能是真菌群中发现的最复杂的阵列，关于交配系统的分子基础的工作将继续进行。交配系统的进化和寄主专门化将通过DNA序列分析开发的系统发育方案来追踪。这些工作将为系统处理这一生态上重要的属奠定基础，并允许对真菌中的物种进行更实用的定义。